Originally Posted by
AndreyT
What the Sheldon Brown's web site is saying about front wheel braking is absolutely correct, if overly theoretical. For any specific rider position (shifted backwards from the saddle or not) the braking force generated by the front wheel alone at its ideal maximum braking force point (as described below) will always be greater than the sum of front and rear braking forces at any other (non-ideal) point. (Assuming, of course, that the wheel-to-road traction is sufficient to achieve that braking force).
For each given rider position, maximum braking force is achieved with front wheel braking only. And it is achieved when the the rear wheel bears 0% of the bike weight, i.e. at that exact point when the rear wheel makes that "infinitely light" contact with the ground. Of course, in this configuration the rear wheel has no traction at all. I.e. its is either about to lift from the ground (if pushed forward/up) or it is about to skid (if pushed sideways). In such situation there's no difference whatsoever between the root reason for these two scenarios.
This is, again, a misinterpretation of the physics. The maximum deceleration that can possibly be attained is when the normal force on the rear wheel is zero
and when the rider is at the highest possible angle above the front hub. The trick of the math is that this is all that you can get and you can't get no more. Go past this point and you aren't braking...you are falling. In practice, this is not a situation that you want to be in, even in a panic stop. The edge of that balance point is too fine and the ability to go past the point of no return is too easy to use it as a regular tool.
On the other hand, up to the point where the rear wheel leaves the ground (not a skid because the rear wheel is still in contact with the ground), the amount of deceleration that the rear wheel provides isn't zero. On the other hand, when the rear wheel leaves the ground, the amount of lever force is moot anyway so applying the rear brake goes from having an effect, i.e. doing some good, to having no effect but also having no detriment.
Originally Posted by
AndreyT
This inevitably will result in short periods (or long periods, depending on how good the cyclist is) when the rear wheel receives some portion of the bike weight. For this reason it might make sense to apply rear brakes as well, to "pick up" those portions of traction that from time to time "escape" to the rear wheel. Or it might not, since it can lead to rear wheel lock up.
This is sensible and basically states what happens in the real world. You might be able to brake ideally in an ideal world but the world is seldom ideal.
Bottom line: Unless you do a nose wheelie
all the time use both brakes.