Why are the front brakes more powerfull than the rear brakes?I‘m talking about a mountain bike.
Because braking on a bike should be about 70% front, 30% rear. Ever notice that when you pull the rear brake you skid, while pulling the front brake stops you? Take a little time and learn how to place your weight on the back of the bike and stop with your front brake. this is simpler than it sounds and will improve your stopping performance greatly.
The front brakes provide about 70% of the stopping power on ANY two-wheeled machine, including road bikes and motorcycles. the reason is that when you brake, your weight is transferred forward onto the front wheel, pushing the tire harder into the ground and giving it a LOT more grip than the rear wheel, which has just been unweighted. A road bike has powerful dual-pivot brakes up front to take advantage of this, and sport motorcycles have two huge discs for the front brake and a single, smaller one in the rear because of it as well.
This has little to do with bike type, or even bikes. With most any vehicle that experiences weight shift, cars, motorcycles etc included. When stopping, your weight is shifted forward on to the front wheel of your bike and off the rear wheel. Therefore the front wheel has most of the weight on it when braking, traction is mostly on the front wheel traction is what's needed to stop. The brakes themselves aren't what create the breaking power you're thinking of. Cars, for example usually have larger front brakes because that's were the traction is, that's where they are needed.
