Originally Posted by
rm -rf
From Sheldon Brown:
Maximum Deceleration--Emergency Stops
The fastest that you can stop any bike of normal wheelbase is to apply the front brake so hard that the rear wheel is just about to lift off the ground. In this situation, the rear wheel cannot contribute to stopping power, since it has no traction.
and if you think you can yank the front brake and hold it at exactly that point, on the edge of tipping over the front wheel, for the duration of a stop, I would like to see that. A little light use of the rear brake helps fill in with extra stopping power where you don't quite have the guts to push that envelope on the front. Yes, you have to use it carefully to avoid locking up the rear. The rear is also good for other reasons mentioned here - backup, alternating for heat management, slower stops, and most importantly for laying down "awesome patches"