Originally Posted by
tntyz
Try stopping hard while using both brakes. Most of the time the back tire will lock up because there is so little traction as the weight shifts forward. It is obviously supplying some drag (else there wouldn't be that cool-looking black streak on the road), but not much.
I don't think this means that using both brakes is "bad", but locking up a tire is seldom a good idea.
I tend to use the back brake for feathering or loosing a little speed or sometimes right at the end of stopping. Front brake for most of the heavy-duty stuff.
You are locking the rear wheel under hard braking because you don't shift your weight back as you brake harder. The rear brake doesn't provide the stopping power of the front brake but it offers 10 to 20% of the overall braking power of the whole system. Failing to use that 10 to 20% effectively means that you aren't getting the most out of your brakes.
What Sheldon Brown...and others...fail to take into account is that once the rear wheel starts to skid, you've gone past the point of maximum deceleration for the bike. Maximum deceleration is not the point where the rear wheel skids, i.e. lifts off the ground, but maximum deceleration occurs just
before the rear wheel lifts off. Once you've transfered the stopping power of the rear wheel completely to the front wheel, you can't get that 10 to 20% of braking power back...except by releasing pressure on the
front brake. This puts the rear wheel back in contact with the ground and recovers the rear brake's contribution to the deceleration.
Releasing pressure on the front brake is standard mountain bike practice. Braking there is far less efficient than road bike braking because of the the surfaces mountain bikes ride...and stop...on
