by
Rob_h
Tue Sep 16, 2008 9:32 pm
Bike fit is obviously a topic that we could spend hours discussing. Having worked in 2 bike shops over the past few months, I have definitely seen a fair few people who have bikes 2 sizes too big for them. Unfortunately, without a 'professional' fit system in either shop, my colleagues and I measure people up for bikes using the good old fashioned technique of actually getting a person on one!
The main issue i have found with bike sizes is that the sizing refers to bb-seat tube length which is fairly irrelevant when considering the rider. I say this as the seat height can be adjusted over a large range. However, it is the top tube length that is the deciding factor for bike sizing (in my opinion), as it can only be changed minimally before the handling is compromised due to a change in weight distribution.
When I state that a 54cm bike is the 'correct' size for someone that is 5'8", it is more referring to someone with an average proportion of legs/body - and this figure is also suggested by many bike manufacturers as a good starting point. However, a valid point is that many women have longer legs in proportion to their body length, therefore a 54 my be too long and cause them to be stretched out far too much.
Also another consideration is that many riders of the past preferred to ride in a hunched back position whereas today's trend is seemingly towards the more aerodynamic flatter back - tying in with what you said about drag brian.