<P> Disc brakes tend to perform equally well in all conditions including water, mud, and snow due to several factors: </P> <Ul> <Li> The braking surface is farther from the ground and possible contaminants like mud which can coat or freeze on the rim and pads . With rim brakes, the first point that mud builds up on a mountain bike ridden in thick mud is usually the brakes . A mountain bicycle with disc brakes is less susceptible to mud buildup provided the rear frame and front fork yoke have sufficient clearance from the wheels . </Li> <Li> Disc brakes may be made of materials that dissipate heat better than the wheel rim, but undersized sport sized discs will be too small to take advantage of the fact </Li> <Li> There are holes in the rotor, providing a path for water and debris to get out from under the pads . </Li> <Li> Wheel rims tend to be made of lightweight metal . Brake discs and pads are harder and can accept higher maximum loads . </Li> <Li> It is possible to ride a bicycle with a buckled wheel if it has disk brakes, where it would not be possible with a rim brake because the buckled wheel would bind on the brake pads . </Li> </Ul> <Li> The braking surface is farther from the ground and possible contaminants like mud which can coat or freeze on the rim and pads . With rim brakes, the first point that mud builds up on a mountain bike ridden in thick mud is usually the brakes . A mountain bicycle with disc brakes is less susceptible to mud buildup provided the rear frame and front fork yoke have sufficient clearance from the wheels . </Li> <Li> Disc brakes may be made of materials that dissipate heat better than the wheel rim, but undersized sport sized discs will be too small to take advantage of the fact </Li>

When did disc brakes come out for bikes