I notice—and
I’m sure a lot of others do, too—that as “bike fit” gains popularity, stock bike
sizing options become more limited and homogenized. On the one hand, I would think that if
companies are promoting fit systems, these companies would also believe that it
might be prudent to offer bikes in sizes that actually facilitate improved bike
fit, rather than hinder the fitting process.
Interestingly,
overall, that’s not happening. Over the
past decade, more and more bike
suppliers are offering fewer and fewer stock bike sizes. Some major brands offer only six sizes of
bike—bikes that cost more than $8,000.
Take a
simple case of seat tube angle as an example of diminishing choices--although we could choose any frame geometry element and
have the same outcome. The seat tube angle is an important consideration in bike fitting because it determines the rider’s saddle position relative to the bottom bracket and crank
set. This relationship is one of the most
fundamental foundations of bike fit, power output, injury prevention, comfort,
and bike handling. So, one might think
that seat tube angle is fairly important.
Well,
let’s examine four of the best, and most popular, high-end stock road bikes in the US
market. Starting
with the frame size that is closest to a 56.0cm top tube, the seat tube angles
are: