The new version of the Retul software is going to come with video capability so that after capture periods with the infrared portion the fitter can show the client pictures and video of them pedaling to correlate the numbers that the fitter has from the infrared, and give it a second visual aspect.
Why did it take so long to incorporate video? The main reason is that pictures and video are a poor means of measuring in a bike fit. Even with expensive video systems, like the Dartfish video software, it comes down to the user placing points of rotation on a picture, and making measurements based on that. Even with a large LCD display the picture of the cyclist might be 12-15 inches tall, at most, and placing an anchor point at the hip for instance, it would be easy to have it be "off" by a large margin.
In fact, infrared and video systems have been tested side by side, and the video's margin of error consistently comes out to at least 10%. Infrared measuring on the Retul usually runs at a margin of error of 0.2 mm (two-tenths of one millimeter).
Is it a big deal to be that accurate? Even clients who are already pretty happy on their bike, benefit from the infrared because small refinements have shown large gains in pedaling efficiency and power. 10% error is too much to significantly impact aberrant mechanics and fix pain patterns on the bike, but it may help with "showing" clients very gross changes and malalignments.
So I guess it was a pretty good idea that Retul decided to use it this way.
Thursday, December 2, 2010
Tuesday, November 30, 2010
The bike geometry problem
I know I've mentioned this one before, but it continues to cause issues every week, with at least one client that ends up on my fitting table that I need to bring it up again.
Carbon bikes can be a very good thing. They can be comfortable (although often this is not usually a consideration of the stock bike company), they can be light, they can be stiff, and they can look cool. The problem is that now they are cheap. It costs so little to manufacture a carbon fiber bike that often the uber cheap and uber pricey stock frames come off the same lines, from the same hands, lay-up schedule and materials.
Okay, so that is another problem I can get into later. The problem I want to talk about right now is molds. Not like the fungus, but the casts that they create the frames and tubes from. I don't have as big a problem with the frames as the forks. If you look at the geometry charts of any major brand, and if they list the fork dimensions on the website (which more and more often they do not), you'll see that for a particular model the fork axle to crown and rake measurements are the same for every size. Put simply, they use the same fork for every bike from 48 cm up to 62 cm. The head and seat angles (and sometimes the bottom bracket heights) are altered between the sizes. This doesn't seem like such a big deal until you look at the effect some of these angles, coupled with the fork rake measurements affects the handling of the bikes.
In general, the fork and frame angles are great for the "middle" size bikes -- the 54s, 55s, and 56s, or there-abouts. But the small and the large bikes are sacrificed. I've seen 76 degree seat angles on small bikes, and some steep head angles on the bigger bikes.
Not sure if you're bike is affected this way? How does it handle? Are you comfortable descending on the bike? Do you have a "speed wobble"? Even on the flats, do you have trouble holding a straight line?
Unfortunately, this problem is more and more common now with all the carbon manufacturing out there. A well balanced bike fit is one way to lessen the problem, but even this has it's limitations.
Ride well.
Carbon bikes can be a very good thing. They can be comfortable (although often this is not usually a consideration of the stock bike company), they can be light, they can be stiff, and they can look cool. The problem is that now they are cheap. It costs so little to manufacture a carbon fiber bike that often the uber cheap and uber pricey stock frames come off the same lines, from the same hands, lay-up schedule and materials.
Okay, so that is another problem I can get into later. The problem I want to talk about right now is molds. Not like the fungus, but the casts that they create the frames and tubes from. I don't have as big a problem with the frames as the forks. If you look at the geometry charts of any major brand, and if they list the fork dimensions on the website (which more and more often they do not), you'll see that for a particular model the fork axle to crown and rake measurements are the same for every size. Put simply, they use the same fork for every bike from 48 cm up to 62 cm. The head and seat angles (and sometimes the bottom bracket heights) are altered between the sizes. This doesn't seem like such a big deal until you look at the effect some of these angles, coupled with the fork rake measurements affects the handling of the bikes.
In general, the fork and frame angles are great for the "middle" size bikes -- the 54s, 55s, and 56s, or there-abouts. But the small and the large bikes are sacrificed. I've seen 76 degree seat angles on small bikes, and some steep head angles on the bigger bikes.
Not sure if you're bike is affected this way? How does it handle? Are you comfortable descending on the bike? Do you have a "speed wobble"? Even on the flats, do you have trouble holding a straight line?
Unfortunately, this problem is more and more common now with all the carbon manufacturing out there. A well balanced bike fit is one way to lessen the problem, but even this has it's limitations.
Ride well.
Monday, November 15, 2010
Getting a coach
I've been coaching athletes for about 7 or 8 years now, and it grew out of a natural extension of being a physical therapist. As a PT I need to educate and guide my clients in different aspects of their lives (strength, flexibility,nutrition, sleep patterns, body mechanics, alteration of work duties, etc.) to effect a meaningful recovery.
Coaching athletes is at once easier and more difficult than rehab-ing. Easier in the sense that my athletes are willing to do whatever I tell them so that they usually accomplish the goals; harder in the sense that expectations are much, much higher. That part I like.
So what to look for in a coach? I think there are 4 things to look for:
1. Credentials
2. Experience
3. Athletic background
4. Repoire
Credentials can be tricky. There are many "weekend credentials" out there, so don't be fooled. A "CPT" is not a physical therapist, but rather a "certified personal trainer" which is a distinction that can be obtained in a weekend. USA Cycling will certify someone as a "Cycling Coach" by merely completing a take-home test. There are many more out there -- these educational companies are a big business these days, so don't be fooled. Do a little research to find out what it takes to become what your coach has as credentials, and lean toward people with advanced degrees in the field of the exercise science/physiology etc. Although, this too can be a problematic since you can obtain a degree and become a "doctor" from shady "universities" that are unaccredited or have numerous times lost their accreditation, like California Coast University. Bottom line: do some digging, and find out what your coach had done.
Experience: Find out who your coach has worked with. What level of athletes has he or she worked with? Professional? Newbie? As a new-comer to a sport, you may not want someone who works with pros -- they might have a poor understanding of what your needs will be, and certainly the reverse situation wouldn't work very well. every good coach should have a list of athletes with whom you can talk to about their experience.
Your coach's athletic background is just to verify that they have undertaken the sport you wish to train for. You wouldn't want to take advice from someone about how to train for a triathlon when they haven't done one themselves.
Repoire: Your coach should be a good communicator and there should be some semblance of a relationship between the two of you. There is no need to be "buddies" but you do need to be able to talk to each other.
Elite athlete turned coach
I often see ads for former pro and semi-pro athletes hanging out there shingles as coaches once they retire. This seems like a normal progression -- they've spent a number of years preparing themselves for the height of competition, so making the leap to guiding others doesn't sound like a stretch.
The problem with this lies in the reason they excelled at their sport. I know, at first, this doesn't seem like a problem, but put simply, they could be good at their sport in spite of their training techniques. I have read so many accounts of very talented athletes breaking all sorts of basic rules in regards to training that it has become almost routine. There's the short-course triathlete who puts in 750 miles per week on the bike, all at long, slow pace, or the Ironman racer who puts in a 25-mile road run a week before their big race, because they "do better when they ramp up their mileage right up until race day." In most cases, these athletes don't do things as infinitely stupid as this, but they just do what has worked for them, without regard for what might have worked better. Many pro athletes don't alter their programs much from year to year, because "it worked well in the past so why mess with it too much." There is not much understanding of the principles behind exercise physiology and human performance. And, yes, perhaps breaking the rules was exactly what helped them achieve their outstanding results, but just because their top flight physiology responded to it doesn't mean that the average (or even the slightly above average) athlete will.
Elite athletes, I have found, tend to also have a poor grasp of what it "feels" like to only be able to run a 25-minute 5K. They might have broken that threshold before they were a teenager. I have seen a number of programs written for age-group athletes with significantly varying intensities for different intervals, which is great, except that many of these athletes didn't have this many different "speeds." When they run, they may have their marathon pace (which is the same as their pace for any run over 45 minutes) and their 5K pace (pretty much the same as their 10K pace), and that's it. And yet, their coach has prescribed 3 to 4 different speeds/intensities in one single workout.
Time strapped athletes are also often ill-served. I know Chris Carmichael just came out with a book about how to maximize training effect for the busy athlete, but this is not a new idea. There are many of us out here that have been helping guide these athletes with time-saving, effective workouts for more than a decade. I know amateur athletes who have been turned away by a coach because they only had 8 hours a week to dedicate to training. The elite-turned-coach may have a really tough time coming to grips with the fact that their client is making decisions on the road whether to ride 15 extra minutes or to stop early so they can cool down and stretch.
It definitely can be confusing, so do some research and find someone you're comfortable with. If you need to tell them to bump up or back off with the schedule more than twice, then maybe they aren't the trainer for you.
Best of luck
Coaching athletes is at once easier and more difficult than rehab-ing. Easier in the sense that my athletes are willing to do whatever I tell them so that they usually accomplish the goals; harder in the sense that expectations are much, much higher. That part I like.
So what to look for in a coach? I think there are 4 things to look for:
1. Credentials
2. Experience
3. Athletic background
4. Repoire
Credentials can be tricky. There are many "weekend credentials" out there, so don't be fooled. A "CPT" is not a physical therapist, but rather a "certified personal trainer" which is a distinction that can be obtained in a weekend. USA Cycling will certify someone as a "Cycling Coach" by merely completing a take-home test. There are many more out there -- these educational companies are a big business these days, so don't be fooled. Do a little research to find out what it takes to become what your coach has as credentials, and lean toward people with advanced degrees in the field of the exercise science/physiology etc. Although, this too can be a problematic since you can obtain a degree and become a "doctor" from shady "universities" that are unaccredited or have numerous times lost their accreditation, like California Coast University. Bottom line: do some digging, and find out what your coach had done.
Experience: Find out who your coach has worked with. What level of athletes has he or she worked with? Professional? Newbie? As a new-comer to a sport, you may not want someone who works with pros -- they might have a poor understanding of what your needs will be, and certainly the reverse situation wouldn't work very well. every good coach should have a list of athletes with whom you can talk to about their experience.
Your coach's athletic background is just to verify that they have undertaken the sport you wish to train for. You wouldn't want to take advice from someone about how to train for a triathlon when they haven't done one themselves.
Repoire: Your coach should be a good communicator and there should be some semblance of a relationship between the two of you. There is no need to be "buddies" but you do need to be able to talk to each other.
Elite athlete turned coach
I often see ads for former pro and semi-pro athletes hanging out there shingles as coaches once they retire. This seems like a normal progression -- they've spent a number of years preparing themselves for the height of competition, so making the leap to guiding others doesn't sound like a stretch.
The problem with this lies in the reason they excelled at their sport. I know, at first, this doesn't seem like a problem, but put simply, they could be good at their sport in spite of their training techniques. I have read so many accounts of very talented athletes breaking all sorts of basic rules in regards to training that it has become almost routine. There's the short-course triathlete who puts in 750 miles per week on the bike, all at long, slow pace, or the Ironman racer who puts in a 25-mile road run a week before their big race, because they "do better when they ramp up their mileage right up until race day." In most cases, these athletes don't do things as infinitely stupid as this, but they just do what has worked for them, without regard for what might have worked better. Many pro athletes don't alter their programs much from year to year, because "it worked well in the past so why mess with it too much." There is not much understanding of the principles behind exercise physiology and human performance. And, yes, perhaps breaking the rules was exactly what helped them achieve their outstanding results, but just because their top flight physiology responded to it doesn't mean that the average (or even the slightly above average) athlete will.
Elite athletes, I have found, tend to also have a poor grasp of what it "feels" like to only be able to run a 25-minute 5K. They might have broken that threshold before they were a teenager. I have seen a number of programs written for age-group athletes with significantly varying intensities for different intervals, which is great, except that many of these athletes didn't have this many different "speeds." When they run, they may have their marathon pace (which is the same as their pace for any run over 45 minutes) and their 5K pace (pretty much the same as their 10K pace), and that's it. And yet, their coach has prescribed 3 to 4 different speeds/intensities in one single workout.
Time strapped athletes are also often ill-served. I know Chris Carmichael just came out with a book about how to maximize training effect for the busy athlete, but this is not a new idea. There are many of us out here that have been helping guide these athletes with time-saving, effective workouts for more than a decade. I know amateur athletes who have been turned away by a coach because they only had 8 hours a week to dedicate to training. The elite-turned-coach may have a really tough time coming to grips with the fact that their client is making decisions on the road whether to ride 15 extra minutes or to stop early so they can cool down and stretch.
It definitely can be confusing, so do some research and find someone you're comfortable with. If you need to tell them to bump up or back off with the schedule more than twice, then maybe they aren't the trainer for you.
Best of luck
Wednesday, August 11, 2010
The Saddle Library
I consider my business to be a a healthy mix of high end, boutique bike sales, with no nonsense, a lot of bang-for-your-buck services. I don't expect my clients to be wasteful in how they spend money with me.
A few years ago, when I first began using the infrared motion capture system from Retul, I had 2 clients in quick succession who were having significant saddle problems, and their journey to solving this problem followed fairly similar paths. They both did what most people do, and went to their local bike shop and explained that they were having saddle sores/discomfort and were promptly sold a seat that had proved to be very popular with the shop (for whatever reason). Seat went on the bike; seat was ridden. Discomfort persisted.
They then asked a friend, who recommended another seat -- ordered it online; seat went on the bike. Discomfort persisted. They repeated this at a second and sometimes a third bike shop. They now had a collection of four or five saddles a piece and had spent between $400-$500.
They didn't know each other, but they both came to see me for a bike fitting at the recommendation of a mutual friend within a month of each other, and their fittings went very similar. We had left whatever saddle was on there last for the fitting. We made many adjustments (as usual) to the seat, but also to cleats, bar position and even gave them exercises/stretches to help with imbalances when needed.
The result?
This last saddle felt great.
So, fantastic, they had found the saddle that worked for them. As an experiment, I asked them to bring in their "saddle collection" on a few follow ups. I traded out for one saddle and then another and after a week of riding on each in their new position, lo and behold! they all worked pretty well (except for one of them). So really, for the most part, it wasn't the saddle, but the position of the saddle.
I thought this was a pretty cool experiment. Neither client was terribly happy that they had spent hundreds on redundant seats, but they were quite thrilled to finally be comfortable riding their bike long distances again.
So after this experience, I found it ridiculous that there was nowhere that you could test out a new set for a few days at a time without plunking down the cheese to buy it. So I began collecting saddles that were popular with other clients, and pretty soon I had quite a collection. Here are some pictures of just a portion of them:
Now I have saddles from:
WTB
Selle Italia
Fizik
Selle SMP
Terry
Salsa
Selle Royal
Hobson
Profile
And I'm going to be adding soon a few from Prologo, San Marco, and possibly Brooks.
The idea behind my new collection -- or saddle library -- is that clients can "check out" a saddle for a week or two, and actually ride it to see if it's compatible for them, rather than just taking someones word for it. When we find that right saddle and we have it in the right position, then they buy. Hopefully, no more wasting a few hundred bucks on saddles that aren't a good fit.
A few years ago, when I first began using the infrared motion capture system from Retul, I had 2 clients in quick succession who were having significant saddle problems, and their journey to solving this problem followed fairly similar paths. They both did what most people do, and went to their local bike shop and explained that they were having saddle sores/discomfort and were promptly sold a seat that had proved to be very popular with the shop (for whatever reason). Seat went on the bike; seat was ridden. Discomfort persisted.
They then asked a friend, who recommended another seat -- ordered it online; seat went on the bike. Discomfort persisted. They repeated this at a second and sometimes a third bike shop. They now had a collection of four or five saddles a piece and had spent between $400-$500.
They didn't know each other, but they both came to see me for a bike fitting at the recommendation of a mutual friend within a month of each other, and their fittings went very similar. We had left whatever saddle was on there last for the fitting. We made many adjustments (as usual) to the seat, but also to cleats, bar position and even gave them exercises/stretches to help with imbalances when needed.
The result?
This last saddle felt great.
So, fantastic, they had found the saddle that worked for them. As an experiment, I asked them to bring in their "saddle collection" on a few follow ups. I traded out for one saddle and then another and after a week of riding on each in their new position, lo and behold! they all worked pretty well (except for one of them). So really, for the most part, it wasn't the saddle, but the position of the saddle.
I thought this was a pretty cool experiment. Neither client was terribly happy that they had spent hundreds on redundant seats, but they were quite thrilled to finally be comfortable riding their bike long distances again.
So after this experience, I found it ridiculous that there was nowhere that you could test out a new set for a few days at a time without plunking down the cheese to buy it. So I began collecting saddles that were popular with other clients, and pretty soon I had quite a collection. Here are some pictures of just a portion of them:
WTB
Selle Italia
Fizik
Selle SMP
Terry
Salsa
Selle Royal
Hobson
Profile
And I'm going to be adding soon a few from Prologo, San Marco, and possibly Brooks.
The idea behind my new collection -- or saddle library -- is that clients can "check out" a saddle for a week or two, and actually ride it to see if it's compatible for them, rather than just taking someones word for it. When we find that right saddle and we have it in the right position, then they buy. Hopefully, no more wasting a few hundred bucks on saddles that aren't a good fit.
Monday, July 19, 2010
New Zipp carbon clincher 404 -- Updated review
July 25, 2010
You can read below the original post, but for those who have been there already, here is my second take:
I still really am impressed with the wheels. One new thing I noticed was the sound -- or lack there of. Previous versions of the 404 carried the standard whooosh-whoosh sound, especially when you stood up. I guess it was the echo through the carbon of the road. This was much more prominent in the 808 and nearly symphonic in their disc. On the new Firecrest rim it is nearly gone. I honestly don't know why or if it is a good or a bad thing....just something that I (finally) realized.
I rode them in the wind and rain this past Wednesday morning (we had a very rare rainy morning here in the desert). I still found them to handle very well in cross-winds, and the wet-braking was very good. I think most of that can be attributed to the Swiss Stop pads, but I thought it was nonetheless important that braking never got grabby in the wet.
My one knock so far on the wheels is something I knew before I rode them -- the spoke holes are drilled not molded in the layup process. Zipp has been doing this for years, and I here that he tool that accomplishes this very difficult procedure is actually quite remarkable, but in recent years an improvement has occurred elsewhere in the wheel market. At Edge Composites, they have a technique of molding in the spoke holes, and they use a nipples that has a dome top section (the part that fastens to the inside of the rim) that allows the spoke to rotate ever so slightly, if needed to relieve stress. My wheel-builder tells me that the Edge wheels he has built all come out nearly flawless and with great tension. When I heard that Zipp was redesigning the 404 I hoped that hey would find away around the drilling (and prevent the small bend that sometimes occurs in their nipples), but I must say that my wheels have always been so strong it rarely, if ever presented a problem.
That's it for now -- I will update more as I go.
So I'll just get it out of the way and say, I am super lucky to be able to try these wheels. As far as I know they are not shipping them yet, so I know this is pretty sweet to be able to try them early.
Zipp has waited for years to do a full carbon clincher, because they weren't confident that the technology was there. Many of the early versions from other manufacturers had some issues with durability so succeeding iterations tended to be heavy and overbuilt. I remember talking to Zipp engineer Josh Poertner, a few years ago and his basic take on it was "If we can't do it well (strong and light), then we just won't do it yet." (Loosely quoted).
I have been a fan of Zipp products for a number of years, and I've been fortunate to be able to try many different flavors. I was lucky enough to be able to ride a set of custom laced 303s in the Leadville 100 about 8 or 9 years ago, and I always have a couple sets of 404s in the garage.
So, to the new rim:
First, let me say that these rims I received are different from what will be shipped -- they are 28-hole, and given the strength and durability of these I expect that they will ship with spoke counts of something like 16/18 front and 20/24 rear. My wheels are overbuilt, for sure, but I don't mind that so much.
What is glaringly obvious with rims in hand for the first time is the radically different shape from the older 404. They are wider at the spoke bed, wide in the "belly" of the rim, and wider at the brake track. The design is their Firecrest rim design, and it is different. At first look, I thought that these could be ridden on a mountain bike, and might take a 29er tire quite well (Disclaimer: Zipp does not recommend you ride their wheels on mountain bikes or with disc brakes, under any circumstances).
One small bonus is that the tires mounted up easier than on previous 404 iterations. Granted it wasn't overly difficult before to get a tire on but I would occasionally need to use one tire lever at the very end to get it to set. Not so with these. My Zipp Tangente (21mm) tires went on by hand -- not so loose that it concerned me, but I was able to work at it and get the tires on and off by hand. Kind of nice in case of flats later on.
So I just mounted everything up and went on the first ride. The Zipps certainly changed the look of my Seven Axiom SL:
So In know what you're thinking -- new Zipps and a frame pump? Hey call me old school but I hate getting caught out with a dead CO2. And those small pocket size pumps make me feel like JoJo the Circus Monkey as I pump them 8,000 times just to hit 95 psi.
I rode the wheels up here:
The picture is at the top of Little Park Road, which is a twelve mile climb just out of town here. It has some 14% grades but a lot of it in the 5-8% range. Pretty tough for someone in my sorry shape. I knew how the Zipps would climb -- that was not what I was curious about. I wanted to make sure they handled well downhill, see how they tracked on the flats, and what a cross-wind felt with them.
Downhill they were.....disconcerting. I mean that in a good way. I descended the east side of the Monument (Colorado National Monument) and they are so much faster than the Fulcrum "training wheels" I had on the bike I was not prepared for the speed when I entered the first few corners. Eventually I got the hang of it and found the wheels corner very predictably. They almost feel like a really good set of skis on perfect snow -- when you set that outside edge they just rail right through. The braking was predictable and not grabby as it can sometimes be on a carbon brake surface -- I also replaced my SRAM brake pads with Swiss Stop yellow pads for these wheels.
I think the area I was most pleased with is how the wheels act in a cross wind. On previous deep wheels I have ridden (the old 404s among them) I always felt like I was getting pushed around just a little bit in a cross wind. I don't know the mechanics of why these wheels did not, but I didn't get one inkling of this sensation when I rode them. I kept bracing when I felt a strong gust come at me from the side, but it never did push me. This is one area I will report back more on later.
So far I am really impressed. I am sure I will find something I want to change in them, but nothing so far. Stay tuned
-J
You can read below the original post, but for those who have been there already, here is my second take:
I still really am impressed with the wheels. One new thing I noticed was the sound -- or lack there of. Previous versions of the 404 carried the standard whooosh-whoosh sound, especially when you stood up. I guess it was the echo through the carbon of the road. This was much more prominent in the 808 and nearly symphonic in their disc. On the new Firecrest rim it is nearly gone. I honestly don't know why or if it is a good or a bad thing....just something that I (finally) realized.
I rode them in the wind and rain this past Wednesday morning (we had a very rare rainy morning here in the desert). I still found them to handle very well in cross-winds, and the wet-braking was very good. I think most of that can be attributed to the Swiss Stop pads, but I thought it was nonetheless important that braking never got grabby in the wet.
My one knock so far on the wheels is something I knew before I rode them -- the spoke holes are drilled not molded in the layup process. Zipp has been doing this for years, and I here that he tool that accomplishes this very difficult procedure is actually quite remarkable, but in recent years an improvement has occurred elsewhere in the wheel market. At Edge Composites, they have a technique of molding in the spoke holes, and they use a nipples that has a dome top section (the part that fastens to the inside of the rim) that allows the spoke to rotate ever so slightly, if needed to relieve stress. My wheel-builder tells me that the Edge wheels he has built all come out nearly flawless and with great tension. When I heard that Zipp was redesigning the 404 I hoped that hey would find away around the drilling (and prevent the small bend that sometimes occurs in their nipples), but I must say that my wheels have always been so strong it rarely, if ever presented a problem.
That's it for now -- I will update more as I go.
So I'll just get it out of the way and say, I am super lucky to be able to try these wheels. As far as I know they are not shipping them yet, so I know this is pretty sweet to be able to try them early.
Zipp has waited for years to do a full carbon clincher, because they weren't confident that the technology was there. Many of the early versions from other manufacturers had some issues with durability so succeeding iterations tended to be heavy and overbuilt. I remember talking to Zipp engineer Josh Poertner, a few years ago and his basic take on it was "If we can't do it well (strong and light), then we just won't do it yet." (Loosely quoted).
I have been a fan of Zipp products for a number of years, and I've been fortunate to be able to try many different flavors. I was lucky enough to be able to ride a set of custom laced 303s in the Leadville 100 about 8 or 9 years ago, and I always have a couple sets of 404s in the garage.
So, to the new rim:
First, let me say that these rims I received are different from what will be shipped -- they are 28-hole, and given the strength and durability of these I expect that they will ship with spoke counts of something like 16/18 front and 20/24 rear. My wheels are overbuilt, for sure, but I don't mind that so much.
What is glaringly obvious with rims in hand for the first time is the radically different shape from the older 404. They are wider at the spoke bed, wide in the "belly" of the rim, and wider at the brake track. The design is their Firecrest rim design, and it is different. At first look, I thought that these could be ridden on a mountain bike, and might take a 29er tire quite well (Disclaimer: Zipp does not recommend you ride their wheels on mountain bikes or with disc brakes, under any circumstances).
So I just mounted everything up and went on the first ride. The Zipps certainly changed the look of my Seven Axiom SL:
So In know what you're thinking -- new Zipps and a frame pump? Hey call me old school but I hate getting caught out with a dead CO2. And those small pocket size pumps make me feel like JoJo the Circus Monkey as I pump them 8,000 times just to hit 95 psi.
I rode the wheels up here:
The picture is at the top of Little Park Road, which is a twelve mile climb just out of town here. It has some 14% grades but a lot of it in the 5-8% range. Pretty tough for someone in my sorry shape. I knew how the Zipps would climb -- that was not what I was curious about. I wanted to make sure they handled well downhill, see how they tracked on the flats, and what a cross-wind felt with them.
Downhill they were.....disconcerting. I mean that in a good way. I descended the east side of the Monument (Colorado National Monument) and they are so much faster than the Fulcrum "training wheels" I had on the bike I was not prepared for the speed when I entered the first few corners. Eventually I got the hang of it and found the wheels corner very predictably. They almost feel like a really good set of skis on perfect snow -- when you set that outside edge they just rail right through. The braking was predictable and not grabby as it can sometimes be on a carbon brake surface -- I also replaced my SRAM brake pads with Swiss Stop yellow pads for these wheels.
I think the area I was most pleased with is how the wheels act in a cross wind. On previous deep wheels I have ridden (the old 404s among them) I always felt like I was getting pushed around just a little bit in a cross wind. I don't know the mechanics of why these wheels did not, but I didn't get one inkling of this sensation when I rode them. I kept bracing when I felt a strong gust come at me from the side, but it never did push me. This is one area I will report back more on later.
So far I am really impressed. I am sure I will find something I want to change in them, but nothing so far. Stay tuned
-J
Thursday, July 1, 2010
Reader email question
Got this question this week from a reader in Norway, and while it's not the most common, his back problem is more common than people realize:
I have spondylolisthesis grade 3. Bike fitting will be critical as a wrongly fitted bike is very painful.
What are the adjustments I would most likely need on a bike that is basically fitted right for a healthy back?
What are the typical “spondy adjustments”?
I (am) cycling quite a lot today on a hybrid that is 20 inches. I am 172 cm. The bike is maybe too big but it seems my back is better when I am streched forward.
I prefer a lying forward position (racing style) and the large bike size allows the seat to be adjusted forward compared to the pedals. Seat being slightly too low.
But I also want to do off road cycling. Problem is that the off roaders are smaller and more upright. (But there is no point in adjusting the off roader to give me a racing position)
I will be very happy to have some ideas about this from you.
Kind regards
GM
For those unfamiliar, a spondylolisthesis (not to be confused with spondylosis or spondylolysis -- professors in medical and PT schools love to torture first years with the differences between them) is when one vertebral body begins to slip forward relative to the one below it. This slipping forward closes off the space for the spinal cord (within the spinal column/vertebrae) as well as for the nerve roots as they exit the spinal column. Occasionally people even have a "step deformity" where if you run your fingers down the spine you can feel a "step" or a larger bump, which is the now more prominent vertebral body below.
These are tricky and early detection routinely is misdiagnosed as some sort of disk injury. The treatments for disk injury and spondylolisthesis, however, are nearly opposite, so distinguishing is important.
In general, lumbar flexion helps to reduce the slipping vertebra, or puts it in a neutral position -- often clients can feel the bone "click" back into alignment very softly. Lumbar extension, or back bending has the effect of pushing the bone further forward and causing more pain.
These people often get severe symptoms if they sleep on their stomach or have to stand in one place too long.
You'll notice that our friend from Norway is more comfortable in a racing or stretched out position, and he's not alone. My clients with spondylolisthesis often are more comfortable stretched out on their road racing bike, and really can't tolerate their mountain bike due to it's upright position. The upright mountain bike position, like standing in one place, requires active abdominal stabilization in order to keep some "flexion pressure" on the lumbar spine -- or really just to keep the spine in neutral. When we stand in place, our trunk muscles get lazy and we begin to "rest" on the static (non-muscular) structures of the spine, like the spinal ligaments, and more often than not our balance point pushes us into lumbar extension. A very similar thing happens when we are in an upright position on our bike. The stretched out racing position actually removes the need for active muscular stabilization because it aligns the vertebrae in flexion.
So what to do?
The obvious correction would be to set up a mountain bike in close to the same aggressive position that you find on a road bike, but few people want to have this position on their mountain bike because in the wrong terrain it can make it much more likely that you will catapult over the handlebars.
The better fix is a careful positioning of the seat. The tilt of the seat, is the biggest issue. You actually want to err on the side of having the seat level or even tilted slightly up. In order to keep pressure off the perineum (your softer bits) this forces you to rotate your pelvis posteriorly slightly which in turn creates some lumbar flexion, or at least a neutral lumbar spine. The overall reach of the bike should be such that a bit of lumbar flexion can be created without getting too far forward with your position (resulting in the aforementioned trip over the bars), and shouldn't cause your shoulder blades to protract significantly in order to reach the handlebars (you don't want a rounded upper back posture).
This seat positioning is the most important factor, however a very good way to ensure that you have less trouble with your spondylolisthesis is aggressive strengthening of the abdominal muscles. The abdominals are responsible for keeping the spine in a neutral position and preventing that lumbar extension.
So, thank you, for the great question, and please don't hesitate with more.
Stay tuned, as I am fortunate to have gotten my hands on a set of Zipp full carbon 404 clinchers. I will post about them in the next few days.
I have spondylolisthesis grade 3. Bike fitting will be critical as a wrongly fitted bike is very painful.
What are the adjustments I would most likely need on a bike that is basically fitted right for a healthy back?
What are the typical “spondy adjustments”?
I (am) cycling quite a lot today on a hybrid that is 20 inches. I am 172 cm. The bike is maybe too big but it seems my back is better when I am streched forward.
I prefer a lying forward position (racing style) and the large bike size allows the seat to be adjusted forward compared to the pedals. Seat being slightly too low.
But I also want to do off road cycling. Problem is that the off roaders are smaller and more upright. (But there is no point in adjusting the off roader to give me a racing position)
I will be very happy to have some ideas about this from you.
Kind regards
GM
For those unfamiliar, a spondylolisthesis (not to be confused with spondylosis or spondylolysis -- professors in medical and PT schools love to torture first years with the differences between them) is when one vertebral body begins to slip forward relative to the one below it. This slipping forward closes off the space for the spinal cord (within the spinal column/vertebrae) as well as for the nerve roots as they exit the spinal column. Occasionally people even have a "step deformity" where if you run your fingers down the spine you can feel a "step" or a larger bump, which is the now more prominent vertebral body below.
These are tricky and early detection routinely is misdiagnosed as some sort of disk injury. The treatments for disk injury and spondylolisthesis, however, are nearly opposite, so distinguishing is important.
In general, lumbar flexion helps to reduce the slipping vertebra, or puts it in a neutral position -- often clients can feel the bone "click" back into alignment very softly. Lumbar extension, or back bending has the effect of pushing the bone further forward and causing more pain.
These people often get severe symptoms if they sleep on their stomach or have to stand in one place too long.
You'll notice that our friend from Norway is more comfortable in a racing or stretched out position, and he's not alone. My clients with spondylolisthesis often are more comfortable stretched out on their road racing bike, and really can't tolerate their mountain bike due to it's upright position. The upright mountain bike position, like standing in one place, requires active abdominal stabilization in order to keep some "flexion pressure" on the lumbar spine -- or really just to keep the spine in neutral. When we stand in place, our trunk muscles get lazy and we begin to "rest" on the static (non-muscular) structures of the spine, like the spinal ligaments, and more often than not our balance point pushes us into lumbar extension. A very similar thing happens when we are in an upright position on our bike. The stretched out racing position actually removes the need for active muscular stabilization because it aligns the vertebrae in flexion.
So what to do?
The obvious correction would be to set up a mountain bike in close to the same aggressive position that you find on a road bike, but few people want to have this position on their mountain bike because in the wrong terrain it can make it much more likely that you will catapult over the handlebars.
The better fix is a careful positioning of the seat. The tilt of the seat, is the biggest issue. You actually want to err on the side of having the seat level or even tilted slightly up. In order to keep pressure off the perineum (your softer bits) this forces you to rotate your pelvis posteriorly slightly which in turn creates some lumbar flexion, or at least a neutral lumbar spine. The overall reach of the bike should be such that a bit of lumbar flexion can be created without getting too far forward with your position (resulting in the aforementioned trip over the bars), and shouldn't cause your shoulder blades to protract significantly in order to reach the handlebars (you don't want a rounded upper back posture).
This seat positioning is the most important factor, however a very good way to ensure that you have less trouble with your spondylolisthesis is aggressive strengthening of the abdominal muscles. The abdominals are responsible for keeping the spine in a neutral position and preventing that lumbar extension.
So, thank you, for the great question, and please don't hesitate with more.
Stay tuned, as I am fortunate to have gotten my hands on a set of Zipp full carbon 404 clinchers. I will post about them in the next few days.
Monday, June 14, 2010
Why cycling and running/walking have almost nothing in common
In response to the q-factor debate (some people believe that narrower is always better, others feel it matters little) I often hear someone spout that our stance width when we walk (basically how widely spaced our feet are as we walk or run) is only a few inches wide, and therefore a very narrow q-factor is mechanically the best.
My response to this is very similar to one I heard from Keith Bontrager once "I'm not sure what walking and riding a bike have to do with one another." And that's true really, but let's look at the similarities and differences.
Similarities:
First, they are both reciprocal motions, meaning that one leg moves one direction while the other moves the opposite.
They are both weight-bearing activities. The amount of weight-bearing can vary drastically however. Walking slowly may produce ground forces equal to your body weight while running can record forces up to 9 times as high. Cycling on the other hand often runs on the range of perhaps 10% of body weight for very easy pedaling, to usually 30-40% for spinning on the flats, to perhaps at or just beyond one time your body weight (think about the times you have been pedaling uphill and your cadence slows enough, where you have to push on the pedals hard enough that it nearly lifts your butt off the seat -- this is roughly one time your body weight).
I could manufacture more similarities, like the fact that the quadriceps and hip extensors are the prime movers for locomotion in each activity, but this is a bit mundane seeing as how they are also the cause in most other forms of forward movement (skateboarding, nordic skiing, blah, blah, blah).
This is about where the similarities end.
Differences abound, and as you might imagine, I come down firmly on the skeptical side of the narro q-factor debate in cycling.
Firstly, running has significantly greater impact on the skeletal system, and most of these effects are good, since this aids with bone density. Cycling studies in the last 10 years or so have shown some scary results in nearly osteoporotic cyclists at pretty young ages, because they have years of training on the bike which is a limited weight-bearing activity.
Mechanically there is a lot going on that separates running from cycling. In running, you have one foot in contact with the ground for a short period (we call this a closed-chain position), then neither foot contacting, then the opposite foot in contact (walking has a brief phase where both feet are touching the ground at the same time). Cycling, however has both feet fixed to the pedals. In walking/running, when we have one foot in contact with the ground only, this allows the pelvis to unlock on one side, since it is not fixed in a closed-chain commitment (so we can swing our leg freely).
On the bike this doesn't happen. What about the recovery phase of the pedal stroke, you ask? (Recovery being roughly from the 6 o'clock position to about 11 o'clock) In this position the foot isn't bearing down on the pedal, you say? Well, actually, it still is. A perfect pedal stroke would have the recovery leg pulling up on the pedal to assist the other leg in it's downward force, and while it may feel like you do this when you pedal, all the research to date has shown that even the most efficient pedalers in the world do not "pull" their recovery leg up. That leg simply can't move fast enough to get out of the way, and we are left with a downward force on the pedal on the back side of the stroke, so in fact we all actually exert a negative torque on the pedals.
If you've ever been on a Compu-Trainer and used their SpinScan you will notice that with most riders if you look at the polar or the bar graph of the efficiency of each pedal at points of the stroke, that often the right leg will appear to be less efficient in it's power phase (roughly from 2 o'clock to 6 o'clock). Now this could be because of some imbalance causing weakness in the right leg, but more often than not it has nothing to do with the right leg pushing down, and everything to do with the left leg not getting out of the way fast enough.
(Incidentally, this is a very common short-coming to the Compu-trainer technology -- the SpinScan is of very limited value because of it's lack of sensitivity. Whenever I see other technology based on the Compu-trainer's I have to cringe -- the most glaring example being the Dynamic Fit Unit (DFU) from Guru. Here is a machine that costs tens of thousands of dollars and the assessment tool it uses is the 15 year old software and hardware from Compu-Trainer.)
Without getting too much into it (because it could be a post or even a book unto itself) most of us are wired to favor or be dominant on our right sides -- even if we are left handed. Some people think this is because we talk so much and our talk centers are on the left side of the brain which is also responsible for right side motor control, and the talk centers stimulate everything and keep that side of the brain "lit up" -- I think that's a neat theory but I'm not 100% sure I believe all of it. regardless, this right dominance is something I see every day. It is certainly no coincidence that about 75% of us sit slightly to the right side of our bike seat.
So we've established that there are significant differences between walking and cycling in weight-bearing (or what could be thought of as total impact), the fixed foot or closed-chain nature of cycling is different as well. A third area of discrepancy is total range of motion. Walking/running involve moderate amounts of hip extension, while cycling has none.
One of the largest differences is one that I address in every bike fit I do, and that has to do with foot and lower leg mechanics. In walking, our bodies are built to absorb impact (there's that word again) by having the midfoot move and collapse towards the ground after heel strike in order to absorb the energy of the foot making contact with the ground. Cycling has none of this. Part of that has to do with the lack of "impact" on the lower extremity, and the other half is due to only the forefoot being attached to the pedal. Forefoot mechanics factor in heavily in cycling, and they are not very well understood.
(I believe this is the case even in professionals who handle foot mechanics for a living. I have tested dozens of sets of custom orthotics on the infrared system - made by orthotists, podiatrists, doctors, and therapists - and while some didn't cause any problems, many did, and none of them corrected any alignment issues that extended above the ankle. Some actually made the foot more comfortable in the shoe, and that's great, but rarely is it necessary to go custom, and spend $400 in order to accomplish that. I have found over-the-counter inserts to do just fine in these cases)
In cycling, if you can control the forefoot you often have the ability to make corrections at the knee and the hip as well.
So what about running you ask? Haven't you expounded on the benefits of forefoot running postures?
Yes, certainly, I am a believer in...well I wouldn't necessarily say forefoot running because that prompts many people to run on their toes...I would say I'm a believer in not landing on your heels. Does this amount to a similarity between running and cycling? Perhaps, but not a very strong one due to two previously discussed facts -- the much greater impact on the foot in running really affects the demands on the foot (this makes correction of lower extremity mechanics on the bike a bit easier and more subtle), and the fact that our butt is also attached to the seat (which makes correction of lower extremity mechanics on the bike much more difficult).
So, I think it's really difficult to make determinations of cycling mechanics by referencing walking/running. In fact doing so will likely lead you astray and compund problems. You'd really be hard-pressed to find two activities that are more dissimliar in some respects. So be careful, if you are getting bike fit advice, in a bike shop or in a clinic, and the person you're talking to starts referencing walking or running mechanics or studies. Cycling is different and deserves to be distinguished.
My response to this is very similar to one I heard from Keith Bontrager once "I'm not sure what walking and riding a bike have to do with one another." And that's true really, but let's look at the similarities and differences.
Similarities:
First, they are both reciprocal motions, meaning that one leg moves one direction while the other moves the opposite.
They are both weight-bearing activities. The amount of weight-bearing can vary drastically however. Walking slowly may produce ground forces equal to your body weight while running can record forces up to 9 times as high. Cycling on the other hand often runs on the range of perhaps 10% of body weight for very easy pedaling, to usually 30-40% for spinning on the flats, to perhaps at or just beyond one time your body weight (think about the times you have been pedaling uphill and your cadence slows enough, where you have to push on the pedals hard enough that it nearly lifts your butt off the seat -- this is roughly one time your body weight).
I could manufacture more similarities, like the fact that the quadriceps and hip extensors are the prime movers for locomotion in each activity, but this is a bit mundane seeing as how they are also the cause in most other forms of forward movement (skateboarding, nordic skiing, blah, blah, blah).
This is about where the similarities end.
Differences abound, and as you might imagine, I come down firmly on the skeptical side of the narro q-factor debate in cycling.
Firstly, running has significantly greater impact on the skeletal system, and most of these effects are good, since this aids with bone density. Cycling studies in the last 10 years or so have shown some scary results in nearly osteoporotic cyclists at pretty young ages, because they have years of training on the bike which is a limited weight-bearing activity.
Mechanically there is a lot going on that separates running from cycling. In running, you have one foot in contact with the ground for a short period (we call this a closed-chain position), then neither foot contacting, then the opposite foot in contact (walking has a brief phase where both feet are touching the ground at the same time). Cycling, however has both feet fixed to the pedals. In walking/running, when we have one foot in contact with the ground only, this allows the pelvis to unlock on one side, since it is not fixed in a closed-chain commitment (so we can swing our leg freely).
On the bike this doesn't happen. What about the recovery phase of the pedal stroke, you ask? (Recovery being roughly from the 6 o'clock position to about 11 o'clock) In this position the foot isn't bearing down on the pedal, you say? Well, actually, it still is. A perfect pedal stroke would have the recovery leg pulling up on the pedal to assist the other leg in it's downward force, and while it may feel like you do this when you pedal, all the research to date has shown that even the most efficient pedalers in the world do not "pull" their recovery leg up. That leg simply can't move fast enough to get out of the way, and we are left with a downward force on the pedal on the back side of the stroke, so in fact we all actually exert a negative torque on the pedals.
If you've ever been on a Compu-Trainer and used their SpinScan you will notice that with most riders if you look at the polar or the bar graph of the efficiency of each pedal at points of the stroke, that often the right leg will appear to be less efficient in it's power phase (roughly from 2 o'clock to 6 o'clock). Now this could be because of some imbalance causing weakness in the right leg, but more often than not it has nothing to do with the right leg pushing down, and everything to do with the left leg not getting out of the way fast enough.
(Incidentally, this is a very common short-coming to the Compu-trainer technology -- the SpinScan is of very limited value because of it's lack of sensitivity. Whenever I see other technology based on the Compu-trainer's I have to cringe -- the most glaring example being the Dynamic Fit Unit (DFU) from Guru. Here is a machine that costs tens of thousands of dollars and the assessment tool it uses is the 15 year old software and hardware from Compu-Trainer.)
Without getting too much into it (because it could be a post or even a book unto itself) most of us are wired to favor or be dominant on our right sides -- even if we are left handed. Some people think this is because we talk so much and our talk centers are on the left side of the brain which is also responsible for right side motor control, and the talk centers stimulate everything and keep that side of the brain "lit up" -- I think that's a neat theory but I'm not 100% sure I believe all of it. regardless, this right dominance is something I see every day. It is certainly no coincidence that about 75% of us sit slightly to the right side of our bike seat.
So we've established that there are significant differences between walking and cycling in weight-bearing (or what could be thought of as total impact), the fixed foot or closed-chain nature of cycling is different as well. A third area of discrepancy is total range of motion. Walking/running involve moderate amounts of hip extension, while cycling has none.
One of the largest differences is one that I address in every bike fit I do, and that has to do with foot and lower leg mechanics. In walking, our bodies are built to absorb impact (there's that word again) by having the midfoot move and collapse towards the ground after heel strike in order to absorb the energy of the foot making contact with the ground. Cycling has none of this. Part of that has to do with the lack of "impact" on the lower extremity, and the other half is due to only the forefoot being attached to the pedal. Forefoot mechanics factor in heavily in cycling, and they are not very well understood.
(I believe this is the case even in professionals who handle foot mechanics for a living. I have tested dozens of sets of custom orthotics on the infrared system - made by orthotists, podiatrists, doctors, and therapists - and while some didn't cause any problems, many did, and none of them corrected any alignment issues that extended above the ankle. Some actually made the foot more comfortable in the shoe, and that's great, but rarely is it necessary to go custom, and spend $400 in order to accomplish that. I have found over-the-counter inserts to do just fine in these cases)
In cycling, if you can control the forefoot you often have the ability to make corrections at the knee and the hip as well.
So what about running you ask? Haven't you expounded on the benefits of forefoot running postures?
Yes, certainly, I am a believer in...well I wouldn't necessarily say forefoot running because that prompts many people to run on their toes...I would say I'm a believer in not landing on your heels. Does this amount to a similarity between running and cycling? Perhaps, but not a very strong one due to two previously discussed facts -- the much greater impact on the foot in running really affects the demands on the foot (this makes correction of lower extremity mechanics on the bike a bit easier and more subtle), and the fact that our butt is also attached to the seat (which makes correction of lower extremity mechanics on the bike much more difficult).
So, I think it's really difficult to make determinations of cycling mechanics by referencing walking/running. In fact doing so will likely lead you astray and compund problems. You'd really be hard-pressed to find two activities that are more dissimliar in some respects. So be careful, if you are getting bike fit advice, in a bike shop or in a clinic, and the person you're talking to starts referencing walking or running mechanics or studies. Cycling is different and deserves to be distinguished.
Tuesday, April 27, 2010
Sidi shoe and SPD-SL compatibility issue
Ran into a problem with newer model Sidi road shoes (the last few pairs I've had this issue with are the Sidi Genius 5) and SPD-SL pedal/cleat system.
I need to research this further, but my guess is that Sidi, in an effort to continue to reduce the shoe weight and especially to decrease the stack height of the sole, has begun making the sole of the shoes thinner.
I do believe that this is more of an issue with Shimano than Sidi -- I don't have this problem with the Sidi shoes when I use Look pedals or Speedplays.
With the SPD-SLs it's even a challenge to get the screws to "bite", when you try the first-time installation of the cleat -- they just don't seem long enough. When I tried a 12 mm screw, however, it bottomed out before it could ever tighten down on the cleat and washer. Once you do get them fastened with the 10 mm screws it turns out you get only about two (2) turns on the fasteners until they are "tight" -- definitely not very confidence inspiring. Once you do get them fastened, if you need to remove and refasten for any reason, it's much easier the second time as it seems that the threads, which are pressed into the sole of the shoe, "pull out" slightly and seat themselves further toward the cleat side of the sole, which is a fairly common occurance with many shoe threads.
I have heard that there are 11 mm fasteners available to fix the problem -- apparently they "bite" easily when you first put them on, but, based on how early the 10 mm screws bottom out, I can't imagine that the screws that are 1 mm longer are going to tighten very well on the cleat either. Both the 10 and 11 mm should hold initially, but cleat fasteners have a way of unwinding -- anyone who has had a cleat come off mid-ride can attest to this.
I don't have this problem with the Look Keo system at all -- the rectangular washers are thicker, and the entire setup seems to have more leeway built into it, as I am able to shim and wedge the Looks, and I can always find a proper fastener length that works. When I tried to place a varus wedge under one of the SPD-SL cleats, I could not find a length of fastener from my whole trove that was a workable length.
I thought about using a thicker rectangular washer (possibly just substitute in the Looks) and a longer fastener to see if that alows for a bit more thread overlap, but I'm not sure that the fasteners won't protrude below the cleat and 1. contact the ground first when you walk and 2. it may interfere with the engagement on the pedal.
If anyone else has some experience with this combination and has a different, successful solution, I'd appreciate any feedback.
John
Saturday, April 24, 2010
"How did you start doing bike fits?"
I get asked this one nearly every bike fit I do. I can't believe I haven't just written it down -- maybe it would save me from repeating it 200-300 times a year. Not that I mind terribly; after 14 years of doing 1-on-1 client interaction you get pretty good at talking while you work.
So here it goes:
I have been into bikes since I was about 5. I can remember my first bike -- it was a hand-me-down (of course, in a family of 7 kids) that was rattle-canned copper by my Dad. My Dad and my older brother, Mike, taught me to ride and for the next 8 years or so that is all I did; how I got around the neighborhood; how we played in the "court" (the cul de sac, for you non-Mid Westerners) up the street.
On through high school and then into college where I used my bike to commute to class and eventually got into triathlons.
I graduated from Physical Therapy school and advanced into longer distance triathlons (up to Ironman) and then quickly into mountain biking as well and eventually 24-hour racing in my early 20's.
As you can imagine, I attracted a lot of training partners who thought as I did, that long races were fun -- especially when you weren't gifted with natural speed. When you are a physical therapist, family and friends frequently pick your brain about aches and pains they have, and I was happy to help, since turnabout is fair play -- free investing, home buying, and tax advice easily offsets the time spent on PT stuff.
Often, a quick test or two will reveal the problem with some joint or muscle, but with my cycling friends, they often only had the problem when they were riding. The next logical step? Well, we need to see you on your bike!
There is started, and stayed, for a couple years -- I would just help out a friend or 10 with biomechanical issues on the bike.
Of course, I went searching for help, and any existing information on bike fitting. I read everything I could get my hands on -- some of it made sense, most of it didn't ("So if I'm sitting on the bike and look down, my front hub should be obscured by my handlebar? Why?").
I quickly realized that most of the "rules" were arbitrarily set, and very little research had actually been done to back any of it up. When I first started, the static bike fit system were popular -- Fit Kit, Wobblenaught and the like. In these systems you take measurements of your body, like arm, leg, torso measurements, and plug them into an equation which spits out your fit parameters. You input you body's measurements and the "system" tells you how far to place your bars from your seat, how far behind the bottom bracket your seat ought to be, etc. etc. etc.
As a PT, where we consider pain patterns, strength, flexibility, age, level of activity, and about 50 other factors, this was distinctly unsatisfying -- and as it turns out, mostly useless in actual bike fitting. This became glaringly obvious when my first commercial (non-friend helping) bike fits were from Wobblenaught and Fit Kit clients who came in wondering why they hurt so much when they rode. I then realized that there was a gap in the market -- there were people that had many troubles with their bike fit and wanted help, and it was clear that the static systems weren't going to help and therefore couldn't fill this niche.
I said, why couldn't I fill it? I started off slow, and part-time, doing perhaps 20-30 fits that first year. I kept growing each year, though, and it became more and more of my business. About 9 years later, I bought my Retul system which helped growth further, as I began to get many more clients from around the state and from out of state, since people were looking for someone that had a way to measure their mechanics dynamically and accurately, paired with having the knowledge and experience to apply all this information.
And so here I am. I'm doing anywhere from 200-250 bike fits a year, building custom bikes:
Oh yeah, forgot to include that - I saw about 5 or 6 years ago that some of the custom bikes my clients had were not made for them very well. Not very custom, which is a crime when you're paying $8000. There were aspects I certainly would have designed differently to tailor the bike to them better and their riding style -- so I did! It is truly a pleasure to build a machine that is meant for that one individual to ride comfortably, powerfully, and efficiently for hours and enjoy it.
So that's it; how I got started. It was a fairly organic and seamless process. I would bet there are maybe a dozen or so people in the U.S. that have the background I have, have been doing it for as long and have the equipment available to them that's necessary for the accuracy desired, and I bet every one of them shed the same amount of blood to get to where they are -- and that's the point. You can't short-cut this trade -- there is too much to know and (still) too little good information out there.
Happy pedaling
John
So here it goes:
I have been into bikes since I was about 5. I can remember my first bike -- it was a hand-me-down (of course, in a family of 7 kids) that was rattle-canned copper by my Dad. My Dad and my older brother, Mike, taught me to ride and for the next 8 years or so that is all I did; how I got around the neighborhood; how we played in the "court" (the cul de sac, for you non-Mid Westerners) up the street.
On through high school and then into college where I used my bike to commute to class and eventually got into triathlons.
I graduated from Physical Therapy school and advanced into longer distance triathlons (up to Ironman) and then quickly into mountain biking as well and eventually 24-hour racing in my early 20's.
As you can imagine, I attracted a lot of training partners who thought as I did, that long races were fun -- especially when you weren't gifted with natural speed. When you are a physical therapist, family and friends frequently pick your brain about aches and pains they have, and I was happy to help, since turnabout is fair play -- free investing, home buying, and tax advice easily offsets the time spent on PT stuff.
Often, a quick test or two will reveal the problem with some joint or muscle, but with my cycling friends, they often only had the problem when they were riding. The next logical step? Well, we need to see you on your bike!
There is started, and stayed, for a couple years -- I would just help out a friend or 10 with biomechanical issues on the bike.
Of course, I went searching for help, and any existing information on bike fitting. I read everything I could get my hands on -- some of it made sense, most of it didn't ("So if I'm sitting on the bike and look down, my front hub should be obscured by my handlebar? Why?").
I quickly realized that most of the "rules" were arbitrarily set, and very little research had actually been done to back any of it up. When I first started, the static bike fit system were popular -- Fit Kit, Wobblenaught and the like. In these systems you take measurements of your body, like arm, leg, torso measurements, and plug them into an equation which spits out your fit parameters. You input you body's measurements and the "system" tells you how far to place your bars from your seat, how far behind the bottom bracket your seat ought to be, etc. etc. etc.
As a PT, where we consider pain patterns, strength, flexibility, age, level of activity, and about 50 other factors, this was distinctly unsatisfying -- and as it turns out, mostly useless in actual bike fitting. This became glaringly obvious when my first commercial (non-friend helping) bike fits were from Wobblenaught and Fit Kit clients who came in wondering why they hurt so much when they rode. I then realized that there was a gap in the market -- there were people that had many troubles with their bike fit and wanted help, and it was clear that the static systems weren't going to help and therefore couldn't fill this niche.
I said, why couldn't I fill it? I started off slow, and part-time, doing perhaps 20-30 fits that first year. I kept growing each year, though, and it became more and more of my business. About 9 years later, I bought my Retul system which helped growth further, as I began to get many more clients from around the state and from out of state, since people were looking for someone that had a way to measure their mechanics dynamically and accurately, paired with having the knowledge and experience to apply all this information.
And so here I am. I'm doing anywhere from 200-250 bike fits a year, building custom bikes:
Oh yeah, forgot to include that - I saw about 5 or 6 years ago that some of the custom bikes my clients had were not made for them very well. Not very custom, which is a crime when you're paying $8000. There were aspects I certainly would have designed differently to tailor the bike to them better and their riding style -- so I did! It is truly a pleasure to build a machine that is meant for that one individual to ride comfortably, powerfully, and efficiently for hours and enjoy it.
So that's it; how I got started. It was a fairly organic and seamless process. I would bet there are maybe a dozen or so people in the U.S. that have the background I have, have been doing it for as long and have the equipment available to them that's necessary for the accuracy desired, and I bet every one of them shed the same amount of blood to get to where they are -- and that's the point. You can't short-cut this trade -- there is too much to know and (still) too little good information out there.
Happy pedaling
John
I'm back; SI joint Part 2; orthotics and cycling
Sorry again for the long delay -- this is such a busy time of year that I barely have time for anything besides bike fits and designing custom machines (and my family of course). This week, I purposely carved out some down time to catch my breath, and (gasp) even get out for a ride or two.
Of note recently: I had another client this past weekend with a clearly restricted SI joint (this time on the right side) and after a couple of tests, she too benefitted from treating that right side as a short right leg. A 3 mm leg length shim did the trick, and really allowed her mechanics to even out and she was sitting more equally on her seat as well. I will post the Retul files once I doctor them to block out her name, etc.
I've also had further reinforcement of my long held belief that custom orthotics do a very poor job of controlling lower extremity mechanics in cycling. I get a number of clients that have orthotics in their cycling shoes, and I routinely test them on the infrared with the orthotics as normal, and then without orthotics but with cleat wedges/shims as needed. I have never had a pair of orthotics do as good a job at controlling the mechanics as the cleat adjustments.
Part of the reason for this is that most people don't have two sets of orthotics made -- they have one set for walking/running made (because they're expensive). Walking/running orthotics WILL NOT help in cycling. They might not harm anything drastically, but they won't help -- the mechanics of running/walking and cycling have very little to do with one another. You can almost say they are opposite mechanical events of each other. Again, the orthotics may not cause harm, and they may even be more comfortable to the foot itself, because of the support it provides, but I have not found them to correct for much past that.
Even second sets of orthotics made (supposedly) for cycling have faired very poorly. My personal guess on this one is that most people making orthotics are not familiar with the mechanics of cycling. These health care professionals are educated in the context of gait training and evaluation. Walking is studying ad nauseum -- the micro-events that occur to the muscles during swing and stance phase, etc. (And, incidentally, they are often very good at assessing gait.) Some programs do not even spend a lot of time on running. The programs will acknowledge that there are significant differences between walking and running, however they often do not spend a lot of time on it. And cycling? Effectively "none" is my educated guess.
So my advice is to not spend another $200-$500 on cycling orthotics, when $30-$40 (max) of cleat wedges and shims is much more effective.
Anyhow, I will post some files to show this in a little bit, and I am making a concerted effort to post more regularly.
Stay tuned.
J
Of note recently: I had another client this past weekend with a clearly restricted SI joint (this time on the right side) and after a couple of tests, she too benefitted from treating that right side as a short right leg. A 3 mm leg length shim did the trick, and really allowed her mechanics to even out and she was sitting more equally on her seat as well. I will post the Retul files once I doctor them to block out her name, etc.
I've also had further reinforcement of my long held belief that custom orthotics do a very poor job of controlling lower extremity mechanics in cycling. I get a number of clients that have orthotics in their cycling shoes, and I routinely test them on the infrared with the orthotics as normal, and then without orthotics but with cleat wedges/shims as needed. I have never had a pair of orthotics do as good a job at controlling the mechanics as the cleat adjustments.
Part of the reason for this is that most people don't have two sets of orthotics made -- they have one set for walking/running made (because they're expensive). Walking/running orthotics WILL NOT help in cycling. They might not harm anything drastically, but they won't help -- the mechanics of running/walking and cycling have very little to do with one another. You can almost say they are opposite mechanical events of each other. Again, the orthotics may not cause harm, and they may even be more comfortable to the foot itself, because of the support it provides, but I have not found them to correct for much past that.
Even second sets of orthotics made (supposedly) for cycling have faired very poorly. My personal guess on this one is that most people making orthotics are not familiar with the mechanics of cycling. These health care professionals are educated in the context of gait training and evaluation. Walking is studying ad nauseum -- the micro-events that occur to the muscles during swing and stance phase, etc. (And, incidentally, they are often very good at assessing gait.) Some programs do not even spend a lot of time on running. The programs will acknowledge that there are significant differences between walking and running, however they often do not spend a lot of time on it. And cycling? Effectively "none" is my educated guess.
So my advice is to not spend another $200-$500 on cycling orthotics, when $30-$40 (max) of cleat wedges and shims is much more effective.
Anyhow, I will post some files to show this in a little bit, and I am making a concerted effort to post more regularly.
Stay tuned.
J
Monday, March 29, 2010
The wife's bike
So any healthy relationship has to have balance. The past few years my wife has been in the enviable position of getting to ride a different demo bike every year, and sometimes having a choice of multiple bikes.
The downside is that in this situation, you don't get a perfectly fit bike most of the time (unless you're lucky, like me, and most size 54/55s are usually pretty darn close. She does have some shoulder problems, however, and that usually causes her to sacrifice her low back in order to maintain a comfortable reach to the bars. Suffice it to say that she tends to leverage a bit more through one side of her lumbar spine, especially when she climbs.
So, finally this year, I decided to surprise her for her birthday with designs for a custom bike "all for her." I decided on Seven's Axiom SL (double butted titanium), which is their workhorse model, a SRAM Force group, FSA K-Wing carbon compact bars, Selle Italia Lady Gel Flow saddle, and I had a pair of Zipp 404 rims lying around that I had Mike at Bigwheels (www.lacemine29.com) lace to some DT Swiss 240s hubs.
I don't have a great creative streak in me so I gave the Seven designers some themes to work with: Ethiopia (our kids are adopted from there), gourmet cooking (my wife, who is a Nurse Practitioner, loves to cook enormous meals on the weekends to the delight of our friends. The painters at Seven cam up with the scheme you see below:
there is an outline of the country of Ethiopia on the top tube, and there are two "Electric Blueberry" panels on the seat and down tubes that have a fleur de lis pattern on them. the fleur de lis has many meanings and references, but it is also the cover for Julia Childs' Mastering the Art of French Cooking.
I think they did well:
The downside is that in this situation, you don't get a perfectly fit bike most of the time (unless you're lucky, like me, and most size 54/55s are usually pretty darn close. She does have some shoulder problems, however, and that usually causes her to sacrifice her low back in order to maintain a comfortable reach to the bars. Suffice it to say that she tends to leverage a bit more through one side of her lumbar spine, especially when she climbs.
So, finally this year, I decided to surprise her for her birthday with designs for a custom bike "all for her." I decided on Seven's Axiom SL (double butted titanium), which is their workhorse model, a SRAM Force group, FSA K-Wing carbon compact bars, Selle Italia Lady Gel Flow saddle, and I had a pair of Zipp 404 rims lying around that I had Mike at Bigwheels (www.lacemine29.com) lace to some DT Swiss 240s hubs.
I don't have a great creative streak in me so I gave the Seven designers some themes to work with: Ethiopia (our kids are adopted from there), gourmet cooking (my wife, who is a Nurse Practitioner, loves to cook enormous meals on the weekends to the delight of our friends. The painters at Seven cam up with the scheme you see below:
there is an outline of the country of Ethiopia on the top tube, and there are two "Electric Blueberry" panels on the seat and down tubes that have a fleur de lis pattern on them. the fleur de lis has many meanings and references, but it is also the cover for Julia Childs' Mastering the Art of French Cooking.
I think they did well:
Saturday, March 20, 2010
Seven Sola S single-speed
I love how this bike turned out. You may have seen it in older posts when I was building it with my new dee-luxe headset press.
Briefly on the build:
It is a full Ti frame with slider dropouts, the brakes are Avid mechanicals (likely upgrade to their Mag CRs in a bit), Seven Kit, Truvativ Noir single-speed crankset, Chris King/DT 470 wheels, matching King headset, Kenda Karma tires, and last but not least a DT Swiss XMC 100 fork. The fork has a huge pricetag ($1400 retail!!) but I was blown away by the suppleness and features on the fork right out of the box. DT says it will "break in" after 20 hours of riding or so, but it felt pretty good on the shakedown ride to me.
Enjoy.
Briefly on the build:
It is a full Ti frame with slider dropouts, the brakes are Avid mechanicals (likely upgrade to their Mag CRs in a bit), Seven Kit, Truvativ Noir single-speed crankset, Chris King/DT 470 wheels, matching King headset, Kenda Karma tires, and last but not least a DT Swiss XMC 100 fork. The fork has a huge pricetag ($1400 retail!!) but I was blown away by the suppleness and features on the fork right out of the box. DT says it will "break in" after 20 hours of riding or so, but it felt pretty good on the shakedown ride to me.
Enjoy.
Wednesday, February 24, 2010
Seven Elium SLX
So this is one of the prettiest custom builds I have ever done. I won't ruin this with too many words. I'll just explain the build:
Elium SLX frame and fork (this is a titanium and carbon mix - everything white is Ti except the fork)
Integrated Seatpost
Campagnolo Record 11 group (oh good God!)
DT Swiss wheelset
3T ergoNova Team bars
Custom Celtic Cross decal
BTW the Integrated seatpost has two seperate bolts to adjust tilt and fore-aft independently of each other -- which is phenomenally convenient -- and when you see the parts machine out of Ti, I can't help but think that there is no way that they make money on that part of the build.
Enjoy.
Elium SLX frame and fork (this is a titanium and carbon mix - everything white is Ti except the fork)
Integrated Seatpost
Campagnolo Record 11 group (oh good God!)
DT Swiss wheelset
3T ergoNova Team bars
Custom Celtic Cross decal
BTW the Integrated seatpost has two seperate bolts to adjust tilt and fore-aft independently of each other -- which is phenomenally convenient -- and when you see the parts machine out of Ti, I can't help but think that there is no way that they make money on that part of the build.
Enjoy.
Thursday, February 4, 2010
Who (or what) do bike companies build bikes for?
The cycling world certainly has gone through a "carbon revolution" in the last 10 years. It is now possible to get a full carbon road bike for under (sometimes well under) $1000. These bikes have distinctive tube shapes, and paint to match.
So what are the upsides of having a carbon bike? Well, carbon bikes can be lighter than other materials. Certainly manufacturers have been able to make the average carbon bike lighter than the average steel, titanium, and possibly aluminum bike. But it is often not the case all the time -- there were many very light aluminum bikes in the day that still hit the 15 or 16 pounds mark. You paid for them, but you pay for these light carbon bikes as well.
Where carbon is supposed to have a leg up on aluminum is in ride quality, feel, road dampening; whatever you want to call it. I think in general it succeeds here. On very long rides, I have noticed less vibration on the carbon bikes I have owned and this, I believe translates into less fatigue. I think this has mostly to do with the central nervous system. Just as being stimulated with loud music or airplane noise can induce fatigue, so to does the buzz on a harsh road bike cause this "central fatigue" (ever notice how LOUD it is on an airplane even when no one is talking -- all that ambient noise has been shown to make you tired.)
This "dampening" quality is very dependent on how the carbon is laid up. In my experience, there are some carbon bikes out there that are just as uncomfortable as the harshest aluminum. If the layup schedule is too rigid or if the epoxy/resin content is not tightly controlled, it is my belief that it can negate the benefits of the carbon in this respect.
So why else do the manufacturers use it?
The main reason now is that it is cheap. You can get carbon fiber cheap, and have it molded into tubes or into a complete bike very inexpensively in Asia. You can teach a heck of a lot more people how to lay carbon material into a monocoque mold or how to wrap joints for tube-to-tube construction methods than you can teach people to weld a perfect joint.
What is being limited are the number of sizes.
This is partially a function of the molds they use to create the bikes. The molds are the expensive part, so if you can get away with 4 or 6 molds (and therefore sizes) rather than 12 sizes you are saving money right off the bat.
The other factor that has precipitated fewer sizes is compact or sloping geometry. With a sloping top tube many more people can physically throw their leg over the top tube to do the "standover test". It's not that more people can fit the bikes, it's that more people can APPEAR to fit the bikes. Back 10 or 15 years ago, before sloping geometries were common, the standover test would at least exclude a few people from being able to buy a certain frame -- their inseam was just not tall enough to comfortably straddle the bike. The standover test, then as now is an awful way to size a bike, but at least back then, there was a certain amount of restriction in bike selection.
I know it sounds like I am really "down" on the manufacturers of today, and...er...well, I am. I should be ecstatic, because as long as they keep doing what they are doing, I will continue to sell a consistent stream of custom bikes to clients who have no chance of fitting a stock bike (this pool of clientele continues to grow every year), as well as doing a few hundred bike fits a year to try and correct for ill-fitting machines.
It doesn't make me happy, however -- I just think about all the people that threw in the towel on cycling because they could not get comfortable on their bike. That stinks. That's not good for anyone's business.
I'm afraid that the story gets a bit worse. There is one more aspect of bike construction that is falling further behind as well. It has to do with the forks. Nowadays it is commonplace to have an entire line of bikes with 2 different offsets, and many are now going to only one fork offset (or rake).
The same reason applies -- a new rake means a new mold, so if you can build just one or two, you're saving money.
This problem is one that has come more to my attention in the few years I have been using the Retul system. After we do the bike fitting we can use the wand, which is called the Zin, and log in the exact dimensions and build of the bike. It is accurate to about 0.2 mm on most bikes and it not only gives you measurements to the bar and seat position, but also gives you the stack and reach of the frame, and the rake and trail of the fork, among many others. You see, you can't always look up the rake and trail of your bike make and model. Many of the manufacturers will asterisk (*) out the fork rake and/or head angle on one or all the models, claiming it is "proprietary" information. I didn't really think much of it until I started to "Zin" some of these bikes only to find out that the rake measurements that were asterisked out were actually the same as the size below it, where it was stated. If it is the same, why the need to hide it? The only reason I can think of is that they don't want you to know it's the same fork.
Why would they not want you to know? Well, we need to do a quick discussion about rake and trail. What is trail?
Trail is the distance between the following points:
1. if you drop a plumb line directly from the front axle to the ground and mark this spot on the ground - basically the tire contact patch
2. project a line through the center of the head tube, and at the same angle, of course, as the head angle until it reaches the ground; mark this point on the ground.
The way you manipulate the amount of trail on a bike is to alter the head angle and/or the rake of the fork.
A simple explanation holds that more trail means more stable (and more "cumbersome" in the extremes) and less trail means less stable (and more "twitchy" in the extremes). Lennard Zinn of velonews.com has written ad nauseum on all the variations in their technical Q&A section -- I definitely recommend reading some of those for more information.
In my experience, for a road bike, a trail measurement close to 60 mm seems to work quite well -- it is a nice balance between stability and yet still have easy to initiate turns.
So now imagine two bikes of the same make and model, just different sizes. The first bike is a 48 cm bike with an effective top tube of 49.1 cm, and the other is a 61 cm bike with a 60 cm effective TT. The smaller bike may fit someone that's 5'2" and the larger perhaps 6'4". When you think of the ways these bikes can be manipulated to fit these drastically different sized individuals you might immediately think of the effective top tube, the head tube length, and the seat and head angles. There are, of course more things to consider, but lets consider only these four things.
Of course the top tube and head tube measurements would have to be scaled up for the bigger bikes and made smaller for the smaller bikes, so we expect those measurements to change. Would the head and seat angles change?
I think it's safe to assume that, in a perfect situation, the seat and head angles would have to change some. Mostly to conform to the limits of 700c wheels -- some of these limits have to do with keeping the wheelbase down or limiting the amount of toe overlap with the front wheel, among other things. As you look on the geometry charts for all of the major stock bike (and by that I mean not custom) manufacturers, you can see this play out -- all of these variables change through the sizes.
Where this breaks down is when you see the fork rake listings (if they even show them). They are very often all the same or at best there are only two different rakes. So if everything about the bikes of different sizes is changing except the rake, and changing rake and head angle are the two main ways of manipulating the trail (and therefore handling) of the bike, then it becomes obvious that they are building the bikes to fit the fork, rather than to fit the rider.
They have excluded rake changes from the equation entirely so they are trying to manage the handling of the bike through the head and seat angle (I know many will say "chainstay length" as well, but have a look on the websites at how many of them change the chainstay lengths through the sizes -- nearly no one) while also making sure to manage toe overlap.
So who wins? Well, the bike companies do for one. But there are certain individuals who can buy these bikes and make out just fine. Generally the forks are made for the "in the middle" sizes -- the 54s and 56s mostly. You can see this bear out on the geometry charts again if they list the "Trail" on the bike you'll see that around the middle sizes the trail comes close to the magical 60 mm number and at the larger and smaller end of the spectrum, it diverges further and further away.
Now there are many out there who will say that no rider can feel the difference between 2 or 3 mm in fork rake and the perhaps 2-3 mm change in trail that happens, and for the most part I would agree with them, EXCEPT when the rider has had to alter the positioning on their bike. What do I mean?
I mean if you have a 25 mm setback seat post, and a 110 mm stem with 6 degrees of rise -- so basically your seat and bar position fall easily within the parameters for contact points that the manufacturer had intended, then changing the fork rake either direction 2 or 3 mm you will likely not feel like much. You are "draped" across the the frame as was intended (read as: your weight is distributed closely to how it was intended to be) and the gross affect of the rake change is muted somewhat.
However, if you had to apply a high rise stem (> 15 degrees of rise) or a particularly short stem (< 90 mm in length) or slide your seat nearly all the way forward or all the way back on the post, then you are more likely to fall near the edge or fully outside of the intended weight distribution continuum of the bike, then an ill-fitting fork offset will cause problems: speed wobble, twitchiness, inability to easily reach for a water bottle, difficulty arcing a smooth turn, etc etc etc.
So if you're having trouble with the handling of your bike, and you're not sure how to fix it, consider how your bike may have been constructed - take a closer look at the geometry on the manufacturers website. Look at your fit -- where are you bars positioned? seat? Hopefully, with some minor changes it can be remedied. If it cannot, dig until you find the culprit and resolve to not let that happen on the next bike.
Ride well.
J
So what are the upsides of having a carbon bike? Well, carbon bikes can be lighter than other materials. Certainly manufacturers have been able to make the average carbon bike lighter than the average steel, titanium, and possibly aluminum bike. But it is often not the case all the time -- there were many very light aluminum bikes in the day that still hit the 15 or 16 pounds mark. You paid for them, but you pay for these light carbon bikes as well.
Where carbon is supposed to have a leg up on aluminum is in ride quality, feel, road dampening; whatever you want to call it. I think in general it succeeds here. On very long rides, I have noticed less vibration on the carbon bikes I have owned and this, I believe translates into less fatigue. I think this has mostly to do with the central nervous system. Just as being stimulated with loud music or airplane noise can induce fatigue, so to does the buzz on a harsh road bike cause this "central fatigue" (ever notice how LOUD it is on an airplane even when no one is talking -- all that ambient noise has been shown to make you tired.)
This "dampening" quality is very dependent on how the carbon is laid up. In my experience, there are some carbon bikes out there that are just as uncomfortable as the harshest aluminum. If the layup schedule is too rigid or if the epoxy/resin content is not tightly controlled, it is my belief that it can negate the benefits of the carbon in this respect.
So why else do the manufacturers use it?
The main reason now is that it is cheap. You can get carbon fiber cheap, and have it molded into tubes or into a complete bike very inexpensively in Asia. You can teach a heck of a lot more people how to lay carbon material into a monocoque mold or how to wrap joints for tube-to-tube construction methods than you can teach people to weld a perfect joint.
What is being limited are the number of sizes.
This is partially a function of the molds they use to create the bikes. The molds are the expensive part, so if you can get away with 4 or 6 molds (and therefore sizes) rather than 12 sizes you are saving money right off the bat.
The other factor that has precipitated fewer sizes is compact or sloping geometry. With a sloping top tube many more people can physically throw their leg over the top tube to do the "standover test". It's not that more people can fit the bikes, it's that more people can APPEAR to fit the bikes. Back 10 or 15 years ago, before sloping geometries were common, the standover test would at least exclude a few people from being able to buy a certain frame -- their inseam was just not tall enough to comfortably straddle the bike. The standover test, then as now is an awful way to size a bike, but at least back then, there was a certain amount of restriction in bike selection.
I know it sounds like I am really "down" on the manufacturers of today, and...er...well, I am. I should be ecstatic, because as long as they keep doing what they are doing, I will continue to sell a consistent stream of custom bikes to clients who have no chance of fitting a stock bike (this pool of clientele continues to grow every year), as well as doing a few hundred bike fits a year to try and correct for ill-fitting machines.
It doesn't make me happy, however -- I just think about all the people that threw in the towel on cycling because they could not get comfortable on their bike. That stinks. That's not good for anyone's business.
I'm afraid that the story gets a bit worse. There is one more aspect of bike construction that is falling further behind as well. It has to do with the forks. Nowadays it is commonplace to have an entire line of bikes with 2 different offsets, and many are now going to only one fork offset (or rake).
The same reason applies -- a new rake means a new mold, so if you can build just one or two, you're saving money.
This problem is one that has come more to my attention in the few years I have been using the Retul system. After we do the bike fitting we can use the wand, which is called the Zin, and log in the exact dimensions and build of the bike. It is accurate to about 0.2 mm on most bikes and it not only gives you measurements to the bar and seat position, but also gives you the stack and reach of the frame, and the rake and trail of the fork, among many others. You see, you can't always look up the rake and trail of your bike make and model. Many of the manufacturers will asterisk (*) out the fork rake and/or head angle on one or all the models, claiming it is "proprietary" information. I didn't really think much of it until I started to "Zin" some of these bikes only to find out that the rake measurements that were asterisked out were actually the same as the size below it, where it was stated. If it is the same, why the need to hide it? The only reason I can think of is that they don't want you to know it's the same fork.
Why would they not want you to know? Well, we need to do a quick discussion about rake and trail. What is trail?
Trail is the distance between the following points:
1. if you drop a plumb line directly from the front axle to the ground and mark this spot on the ground - basically the tire contact patch
2. project a line through the center of the head tube, and at the same angle, of course, as the head angle until it reaches the ground; mark this point on the ground.
The way you manipulate the amount of trail on a bike is to alter the head angle and/or the rake of the fork.
A simple explanation holds that more trail means more stable (and more "cumbersome" in the extremes) and less trail means less stable (and more "twitchy" in the extremes). Lennard Zinn of velonews.com has written ad nauseum on all the variations in their technical Q&A section -- I definitely recommend reading some of those for more information.
In my experience, for a road bike, a trail measurement close to 60 mm seems to work quite well -- it is a nice balance between stability and yet still have easy to initiate turns.
So now imagine two bikes of the same make and model, just different sizes. The first bike is a 48 cm bike with an effective top tube of 49.1 cm, and the other is a 61 cm bike with a 60 cm effective TT. The smaller bike may fit someone that's 5'2" and the larger perhaps 6'4". When you think of the ways these bikes can be manipulated to fit these drastically different sized individuals you might immediately think of the effective top tube, the head tube length, and the seat and head angles. There are, of course more things to consider, but lets consider only these four things.
Of course the top tube and head tube measurements would have to be scaled up for the bigger bikes and made smaller for the smaller bikes, so we expect those measurements to change. Would the head and seat angles change?
I think it's safe to assume that, in a perfect situation, the seat and head angles would have to change some. Mostly to conform to the limits of 700c wheels -- some of these limits have to do with keeping the wheelbase down or limiting the amount of toe overlap with the front wheel, among other things. As you look on the geometry charts for all of the major stock bike (and by that I mean not custom) manufacturers, you can see this play out -- all of these variables change through the sizes.
Where this breaks down is when you see the fork rake listings (if they even show them). They are very often all the same or at best there are only two different rakes. So if everything about the bikes of different sizes is changing except the rake, and changing rake and head angle are the two main ways of manipulating the trail (and therefore handling) of the bike, then it becomes obvious that they are building the bikes to fit the fork, rather than to fit the rider.
They have excluded rake changes from the equation entirely so they are trying to manage the handling of the bike through the head and seat angle (I know many will say "chainstay length" as well, but have a look on the websites at how many of them change the chainstay lengths through the sizes -- nearly no one) while also making sure to manage toe overlap.
So who wins? Well, the bike companies do for one. But there are certain individuals who can buy these bikes and make out just fine. Generally the forks are made for the "in the middle" sizes -- the 54s and 56s mostly. You can see this bear out on the geometry charts again if they list the "Trail" on the bike you'll see that around the middle sizes the trail comes close to the magical 60 mm number and at the larger and smaller end of the spectrum, it diverges further and further away.
Now there are many out there who will say that no rider can feel the difference between 2 or 3 mm in fork rake and the perhaps 2-3 mm change in trail that happens, and for the most part I would agree with them, EXCEPT when the rider has had to alter the positioning on their bike. What do I mean?
I mean if you have a 25 mm setback seat post, and a 110 mm stem with 6 degrees of rise -- so basically your seat and bar position fall easily within the parameters for contact points that the manufacturer had intended, then changing the fork rake either direction 2 or 3 mm you will likely not feel like much. You are "draped" across the the frame as was intended (read as: your weight is distributed closely to how it was intended to be) and the gross affect of the rake change is muted somewhat.
However, if you had to apply a high rise stem (> 15 degrees of rise) or a particularly short stem (< 90 mm in length) or slide your seat nearly all the way forward or all the way back on the post, then you are more likely to fall near the edge or fully outside of the intended weight distribution continuum of the bike, then an ill-fitting fork offset will cause problems: speed wobble, twitchiness, inability to easily reach for a water bottle, difficulty arcing a smooth turn, etc etc etc.
So if you're having trouble with the handling of your bike, and you're not sure how to fix it, consider how your bike may have been constructed - take a closer look at the geometry on the manufacturers website. Look at your fit -- where are you bars positioned? seat? Hopefully, with some minor changes it can be remedied. If it cannot, dig until you find the culprit and resolve to not let that happen on the next bike.
Ride well.
J
Wednesday, January 27, 2010
Have a short leg?
I had a really interesting client last week. Her Retul file was showing that she was sitting off to the side of her seat -- her sit bones weren't square on the saddle. That's not strange at all; in fact almost everyone I fit starts with some "skewed" sitting posture.
But with her all signs were pointing to her having a functional leg length discrepancy. A functional leg length discrepancy is when one leg "acts" longer than the other. We don't know for sure without full length leg X-rays whether someone has an anatomic leg length discrepancy, which aren't very convenient when coming in for a bike fit. Only in rare or severe cases do I insist on having this done.
A leg can *act* longer for a lot of reasons. Possibly a restricted hip on the opposite side, a rotated pelvis that manifests on the bike (not all pelvic rotations show up on the bike as well as in standing -- pretty interesting fact on its own), a curvature or scoliosis of the spine, and a number of others.
I ruled out all the usual suspects one by one -- her hips were fairly equal in their mobility; no pelvic obliquity (rotation) at this time (although this had been a problem in the past), and on and on.
Finally we found it -- one of her SI (sacro-iliac) joints was stuck. The SI joint is where the pelvis and the tailbone meet. Those little dimples you sometimes see on someones low back just above their rear end mark where the SI joints lie.
There is not a lot of movement at the SI joint but it does need to help the "pivot" to allow full hip translation as we descend through our pedal stroke.
Her left SI joint was not moving and didn't allow this translation -- it was almost as if her left hip hit a *stop* as she reached down to dead bottom center and her left knee was forced to extend much more than her right in order to complete the pedal stroke. But the damage was done at this point in the pedal stroke and all sorts of aberrant movements were forced -- left hip bobbing, knee lateral travel, etc. etc.
But with her all signs were pointing to her having a functional leg length discrepancy. A functional leg length discrepancy is when one leg "acts" longer than the other. We don't know for sure without full length leg X-rays whether someone has an anatomic leg length discrepancy, which aren't very convenient when coming in for a bike fit. Only in rare or severe cases do I insist on having this done.
A leg can *act* longer for a lot of reasons. Possibly a restricted hip on the opposite side, a rotated pelvis that manifests on the bike (not all pelvic rotations show up on the bike as well as in standing -- pretty interesting fact on its own), a curvature or scoliosis of the spine, and a number of others.
I ruled out all the usual suspects one by one -- her hips were fairly equal in their mobility; no pelvic obliquity (rotation) at this time (although this had been a problem in the past), and on and on.
Finally we found it -- one of her SI (sacro-iliac) joints was stuck. The SI joint is where the pelvis and the tailbone meet. Those little dimples you sometimes see on someones low back just above their rear end mark where the SI joints lie.
There is not a lot of movement at the SI joint but it does need to help the "pivot" to allow full hip translation as we descend through our pedal stroke.
Her left SI joint was not moving and didn't allow this translation -- it was almost as if her left hip hit a *stop* as she reached down to dead bottom center and her left knee was forced to extend much more than her right in order to complete the pedal stroke. But the damage was done at this point in the pedal stroke and all sorts of aberrant movements were forced -- left hip bobbing, knee lateral travel, etc. etc.
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