FasTrack wrote:
> What is the therory why smaller road bikes have steep seat angles?
>
> Most smaller bikes have 74-75 degreee seat angles...
Small frames with big wheels often have to resort to various levels of
bogosity in frame design.
> What would a 72 degree seat angle do to a say 50cm or smaller road
> frame?
If you kept the short top tube that should be on such a small bike,
there'd be excessive toe overlap of the front wheel.
As a work-around to this problem, some manufacturers make the head angle
shallower, some make the seat angle steeper, some a little of both.
None of these changes improve the ride or handling of the bike.
The steeper seat angle leads to the rider putting more weight on the
handlebars.
Shallower head angle could be OK if the fork rake were also increased to
provide a desirable amount of trail. Unfortunately this is not always
done. The guys who design such bikes never ride the smaller sizes.
The real answer is smaller wheels, or at least a smaller front wheel.
Sheldon "Georgena Was Right" Brown
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| If I have been able to see farther than others, |
| it was because I stood on the shoulders of giants. |
| -- Sir Isaac Newton |
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Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
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