Which is more effective a large brake or small brake in a bicycle?

Answer 1

Better isn't that simple, it depends on your priorities. Hydraulic disc brakes with big rotors are most powerful, followed by hydraulic rim brakes. Lightest are single-pivot caliper(rim) brakes. Least maintenance are drum/roller brakes.

Answer 2

Bicycle brakes are more commonly discussed according to type rather than size.

The only time size would be useful is when talking about disc brakes, as the rotors are available in different sizes while all other parts remain the same.

And it's not really much of an issue about effectiveness either. Unless the rider has reduced hand strength, any brake type(if properly adjusted) can be strong enough to lock the wheel up.

A bigger rotor will create more braking force at the same amount of hand effort, so they can provide a bit more fine tuned control than a smaller rotor.

If you're doing really long descents, a bigger rotor won't get as hot as a smaller rotor

Answer 3

It depends a bit on riding surface and rider skill, but generally the front brake is more important.

When you brake on any vehicle something called dynamic weight transfer happens, and this will, for a moment, shift your weight forward.

Like if you're walking, and suddenly stop. If you don't put out a foot, you'll topple forward.

On a vehicle that is short front-to-back, like motorcycles and bicycles, this effect is so big that it can actually lift your rear wheel off the ground.

On a bicycle, it's even worse, as most of the weight - the center-of-gravity - is quite high off the ground.

Cars are bigger, taller front-to-back, and have a lower center-of-gravity.

Because of that, generally the front wheels will begin to skid before the rears come off the ground.

Now, for a given surface, how hard you can brake w/o a wheel starting to skid depends on the amount of weight on the wheel.

So even if you don't let the rear wheel get airborne it will go light, and lock up even at very little brake pressure.

The front OTOH is suddenly seeing even more weight than usual, and can take more braking w/o locking up.

So for a short stopping distance on a good surface the front brake is more important on short-and-high vehicles like motorcycles and bicycles.

But you need to have some riding skills.

Bicycles and motorcycles don't have seat belts, so you need to brace yourself against the bars to avoid being thrown forward.

If you want to brake hard, you need to try to shift your weight to the rear-and-down, to reduce the risk of toppling forward. You also need to be ready to ease up on the brake, if the rear wheel would come off the ground.

A rear brake is mainly important if you are riding on poor and slippery surfaces. It's a lot easier to recover from a rear wheel skid than from a front wheel skid.

It can also be useful if you have to do really long descents. On long descents, using one brake only might cause it to overheat, so using the rear can be rea important.

And of course a rear brake can be real handy as a back-up.

Should the front fail, you still have one left to control your speed with.