Originally Posted by
Right Said Fred
What is the reasoning behind staggering the depth of the wheels with the deeper rim on the rear? Doesn't the front wheel contribute more to the aerodynamic profile than the rear? Wouldn't you want the deeper section wheel on the front if they were not the same?
You're right. I used to run a front TriSpoke/HED3, with a (much lighter) non-aero rear wheel. I did this for a few years in crits.
However, in the real world, with gusty wind, you'll end up with slightly more compromised handling if you run a "big aero" wheel up front, esp if you're exceeding 45-50 mph on the bike (descents typically, or if you draft trucks etc). The front wheel can take you out in a heartbeat if you're not paying attention. Even if you are paying attention a front disk wheel, even as small as a 24" wheel, can take you literally across the road (as happened to me, and I was conscious this might happen). This is why front disk wheels aren't allowed in many time trials on the open road.
A tall rear wheel is almost never going to cause significant handling problems - in fact it usually stabilizes the bike. I've used a disk rear wheel in crits in gusty oceanside airfield races (i.e. significant gusts from all directions), combined with a box section front wheel (and, in one race in particular, I made it into a 3 man break, took my pulls, etc, which is totally unlike me).
I've said this before but my ideal set up would be a light but very tall rear wheel (90-100mm) with two or three front wheels, a short one, a medium one, and a tall one. For me weight becomes significant once the wheelset hits around 1700g so I'd rather keep the weight down than get a taller wheel.