"Play" in frame sizing
12-12-12 | 01:26 PM
#51
Voice of the Industry
Joined: May 2007
Posts: 12,572
Likes: 8
And eliminating the fork length does what for fit? You can't ride a bike without a fork and the length of a fork is an important part of how far up the front end of the bike is pushed. If as cyclezen states the reach and stack comes from mountain biking, eliminating the fork length from the fit is even sillier. When you can have forks that runs from 80mm of travel to 300 mm, that's a lot of variance in the head height and it will have a huge impact on size frame the rider needs.
The fit of a bicycle isn't that hypercritical. If it were, we'd have stems that are available in many more lengths than what are currently available. We'd also find bikes with much more variance in frame dimensions which really don't vary all that much from manufacturer to manufacturer when comparing bikes for similar uses.
Again, if the seat tube angle varied much, you might have a valid point but the seat angle doesn't vary all the much within classes of bikes for similar applications.
In the end, fit is all about getting into the right ball park and then adapting the flexible part of the system...the rider...to the inflexible part of the system...the bike. Fit matters but only up to a certain point.
The fit of a bicycle isn't that hypercritical. If it were, we'd have stems that are available in many more lengths than what are currently available. We'd also find bikes with much more variance in frame dimensions which really don't vary all that much from manufacturer to manufacturer when comparing bikes for similar uses.
Again, if the seat tube angle varied much, you might have a valid point but the seat angle doesn't vary all the much within classes of bikes for similar applications.
In the end, fit is all about getting into the right ball park and then adapting the flexible part of the system...the rider...to the inflexible part of the system...the bike. Fit matters but only up to a certain point.
The concept at play here is the same comment I made to the lady who shares the bike with her son. To some...lets say the average guy who has no road bike experience, if you give him a new road bike for Christmas that is in the ballpark of size, they adjust the saddle and off they go. They don't know what good fit is. You may or may not fall in this camp. But to some...me...fit matters...a lot. Lance Armstrong was said to be able to feel a 1mm difference between his race bikes. I believe it. I know I can feel 2-3mm. Your comment to me about sta couldn't be more off base. It is one of the most important elements of fit to me. I prefer a bike with 72-72.5 deg sta and yet ride a bike with 73.0 deg sta. There are many bike out there I wouldn't consider because I don't want a 73.5 deg sta and ride a 30mm+ setback post. The same applies to proper top tube length for the stem length I prefer and head tube height for stem rise and/or spacer stack. So I agree with Dave. If you are fussy about fit which to me is the key to not only performance but comfort on long rides, then you are going to seek a very particular geometry. Some will even go custom.
