really need to be higher for a woman.
Another solution has been to use a smaller front
wheel. This allows a shorter front center, but having
two tire sizes, two tube size, two rim sizes, etc. causes
some maintenance headaches for riders.
Our engineers evaluated all this and decided that to
get the best overall fit, AND PERFORMANCE, smaller
wheels front and rear coupled to an entirely new geom-
etry was the best way to solve the small rider fit. An
important point here is that although the frame engi-
neers were working on women's solutions, many small-
er males may find that these bikes ride better than past
compromises they've made to get a good fit.
Smaller wheels
Most sizes of WSD road bikes use a 650c diameter
wheelset. To properly position the handlebars and avoid
excessive toe-clip overlap, they have to use smaller
wheels. On the plus side, smaller wheels are easier to
accelerate. They present less frontal area, making them
more aerodynamic. No wonder we also use the smaller
wheel size on our built-for-speed Hilo tri bikes.
Using smaller wheels has many effects on the bike
design. Instead of being forced into particular angles
to accommodate an ill-fitting wheelset, 650c wheels
allowed our engineers the freedom to pick the exact
angles that would yield the best ride. It also allows more
`normal' tubing lengths so the bike has the normal flex
and liveliness `big' people expect from their bikes. Better
fit. Better feel. Better function.
For better fit, we started by offering a shorter top
tube. Previous attempts used a radically slack head
angle and steep seat angle to shorten the top tube.
While Trek women's geometry is different than men's in
this respect, our shorter top tube is not at the sacrifice
of handling. The head angles are slightly more relaxed,
but this is to add steering stability, not toe clip clear-
ance. Toe clip clearance is adequate on even the smallest
frame size, assuming that the small rider also has small
feet. But women riders do not have as much weight in
their shoulders as a man of similar height. That weight
works with trail to provide steering stability and track-
ing on a bicycle. The WSD head angles are tuned just to
provide good handling.
Another special detail we've added is to address the
lower centripetal force generated by the smaller diam-
eter wheel. The wheel's rotation provides a stabilizing
force much like a gyroscope. The lighter the wheel, or
the closer to the hub the mass is located, the lower this
force is. Since this force provides stability coupled with
trail, we use a shorter fork rake (offset) to add trail.
The result is a bike that handles neutrally, even with the
lighter, smaller wheel. Yet those smaller wheels really
accelerate, so a smaller person who might not have the
horsepower of a bigger rider can really move. Fun. And
fast!
Trek 2002 Tech Manual
