I do this all the time on my road bike -- but once a couple of summers ago I decided to try it on the TT bike. Down into the "pozish" I go, absolutely flying (just over 80km/hr if I recall), and then I squeeze the down tube with my knees, like usual, and all of a sudden I am squeezing the front tire with my knees and friction burning two patches onto each leg because I've squeezed the tire instead (shorter frame by quite a bit). YOWCH.
-Eric
-Eric