Many bicyclists fear using the front brake because they believe it, in contrast to the rear brake, might cause the bicycle to overturn. What is not apparent, is that overturning a bicycle with the front brake is much harder than it seems, and that braking itself, is not the cause of most pitchovers.
The primary cause of bicycle pitchover, is that the bicycle stops and the rider does not, after which the bicycle overturns when the rider's thighs strike the handlebars. Overturning can be simulated by walking next to the bicycle, both hands on the bars, and applying the front brake to raise the rear wheel. This experiment should make apparent how small a force will overturn the bicycle when it stops and the rider does not.
Beginners overturn when they use the front brake because they are not aware that, unless they brace with their arms, only the friction on the saddle prevents the bicycle from stopping without them. However, even riders, who don't make this mistake, can pitchover from a front-wheel jam that leaves no time to react. A stopped rear wheel usually does not cause pitchover, because even if the rider moves forward, he unloads the rear wheel, effectively releasing the brake.
Typically, front wheel jams occur from a stick in the spokes, a fender jamming into the fork crown, a front cantilever straddle cable falling onto a knobby tread, or a retaining bolt of a caliper brake releasing from the fork crown. These are unanticipated events for which a rider cannot brace if not already doing so. However, on clean pavement a front wheel jam will overturn the bicycle regardless of rider reaction.
That bicycles do not easily overturn by braking becomes apparent by attempting to raise the rear wheel, preferably at modest speed and while bracing with the arms. The front brake, the principal stopping and speed control device on motorcycles and cars, is especially important for bicycles, whose short wheelbase causes even more weight to transfer to the front wheel while braking, thereby making the rear brake less effective. Therefore, the front brake should be understood and used properly rather than being maligned as it is.
Formerly bicycles in the USA had their front brake on the right hand as do motorcycles. A concerted effort by right handed safety advocates, moved the "dangerous" front brake to the left hand, where it could do less harm, and there it remains today.
By Jobst Brandt, email@example.com