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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


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


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.