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Wednesday, September 25, 2013

Disappearing Bikes: what happened to all the bike sizes?

"Duh" would be an appropriate response to me saying that most of the bike industry is given over to carbon.  Clearly that's the case, and we've benefited by getting lighter and occasionally more comfortable frames and components.

Did ya ever wonder what, if anything, we lost or gave up?
Bikes that's fit well

Bike manufacturers, like any other business, always want to save money and increase their profit margin.  Carbon molds, from which the bikes are made, are expensive, so making fewer molds saves money.  Fewer molds means fewer sizes  
Stock (as in non-custom) manufacturers say they can fit 85%-90% of the population, and while it’s technically true that they make bikes that fit people from 5’1” to 6’”4”, and it’s technically true that 85%-90% of the population is within this height range, what it doesn’t say is that there are more people falling between sizes because there just aren’t that many of them.  
Not too long ago many (but certainly not all) manufacturers made bikes from 48cm to 62cm in 1-2 cm  increments (so 7 - 14 sizes).  Sound like overkill?  A great side benefit of this was that if someone was sold a bike that was the wrong size, which of course did happen, it wouldn’t be off by much.  Now, with so few sizes, when your local shop gets it wrong, which still happens a lot, it’s a much bigger problem.  
In fact I see many clients, that are generally very average in their height, arm reach, flexibility, etc and there still isn’t a good stock option for them…..none of the sizes are a good match.  “Custom bike for them!” you say?  True, but there used to be a time when custom bikes were necessary for the very tall, the very short, or someone with a unique physical attribute that required custom adjustment (of course there is always the sage individual who understood all the benefits of a bespoke bike and just wanted one).  Now, however, custom bikes are being made more and more often for riders who just happen to be in-between sizes.
The trend of fewer sizes carries into the forks that are made as well.  Carbon forks come from carbon molds, so making fewer fork molds saves money too.  Making only one or two fork rakes to fit all the sizes of a bike model often makes for some sketchy handling.  Frame and fork need to work hand in hand with one another and if a less than ideal fork size is used just because it’s convenient, it can lead to some very poor handling. If your bike doesn't feel stable when you descend, or you're unable to ride no-handed you might be experiencing some of this.
The largest factors involved in how a bike handles in order of importance are:
  1. the fit of the bike - fit determines weight distribution and how your body weight “drapes” over the bike
  2. proper front axle placement - if your fork rake is off or not ideal then your bike will feel either twitchy/sketchy (i.e. it deviates off a straight line too easily) or too ponderous (it’s difficult to get into and out of a turning radius)
  3. bottom bracket drop - think of this controlling how high your center of mass is while you sit on the bike.  Smaller bikes will generally have lower bottom brackets (therefore more drop).
  4. proper rear axle placement - chainstay length is the main determinant here, and generally, bigger bikes should have longer chainstays so that the high saddle position of taller riders doesn’t cantilever their weight way out behind their rear axle.
So here are some numbers from some of the larger manufacturers.  This is by no means a comprehensive list, but rather, I tried to survey the most popular bike models among these brands.
Trek - Men’s: up to 7 sizes and 2 different forks, 3 bottom bracket drops; Women’s: 6 sizes, 1 fork, 1 chainstay length, (effectively) 1 bottom bracket drop Overall grade: 7.5/10
Trek does make some women’s WSD bikes with more sizes, but when you look at the geometry like Domane and Madone WSD models, their geometry doesn’t vary from the men’s bikes in any meaningful way -- so…..they’re not really made for women.
Note: When I mention “effectively 1 chainstay” it just means that technically there is a second size but it is so small a difference that renders it basically irrelevant.
Cannondale - Men’s: 6-8 sizes, 1-2  forks, (effectively) 1 chainstay length, 3 bottom brackets drops (but barely) ; Women’s: 5 sizes, 2 forks, 1 chainstay, 1 bottom bracket drop  Overall Grade: 6.5/10
Specialized - Men’s: 5-6 sizes, 1-2 forks, 2-3 chainstay lengths, 3 bottom brackets; Women’s: 5 sizes, 2 forks, 2-3 chainstay (effectively) 1 bottom bracket drop Overall Grade: 6.5/10
Giant - Men’s: 6 sizes, no information on forks, 1 chainstay; Women’s: 3-4 sizes, no info on forks, 1 chainstay Overall Grade: 4/10
Felt - Men’s: 6 sizes, 3 forks, 4 chainstay lengths, (effectively) 1 bottom bracket drop; Women’s: 4 sizes, 1 fork, 2 chainstay lengths, 1-2 bottom bracket drops Overall Grade: 7/10
Note:  I figured someone would ask “well, what about Wilier?” since that’s the main stock brand I carry.  If you consider me putting this in here to be spam, then feel free to skip past it, I won’t mind.  Otherwise, here you go:
Wilier - Men’s: 6 sizes, 3 forks, 5-6 chainstay lengths, 3-4 bottom bracket drops; Women’s: 3 sizes, 2 forks, 1 chainstay, 1 bottom bracket drop Overall Grade: 8.5/10

I broke things up into Men’s and Women’s flavors here for illustrative purposes.  The idea of a women’s specific bike, as in “are women’s specific bikes even necessary?”  is another blog post unto itself.  As you can guess, I don’t think they are necessary, so my bias led me to not weight the poor geometry available among the brands too heavily against them.
I’m not a complete curmudgeon.  I do think that there are huge benefits to today’s bikes…..if you’re the right size.  The advancement in components alone are worth the price of admission.  I think there’s work to be done, though…..

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