Originally Posted by Triguy
This is not quite right. Most windtunnel testing suggests that anytime you are going above 14 mph you should be in your aero position because the decreased wind resistance is significant. Plus, your average ironman pro is more in the 22.5mph-25mph range and I guarantee the aero position helps them a bit.
Though you are correct that they are designed for the aero position and that the aero position has it time and place, mostly triathlons and TTs.
30-35??? sounds a bit fast for any distance to me.
Dave Zabriskie's time trial in the 2005 TdF was an average speed of 54.676km (or 34 mph). Yeah, that's a bit fast, I'd say.