I saw a couple of mountain bikes with dual disc brakes. Is it really necessary. My 100cc motorcycle had no disc brake and even my 450cc motorcycle only had front disc brake. Even new small size motorcycles don‘t have dual disc brakes.
They are necessary for any bike that will be ridden on serious terrain. but not for the reason you're assuming. It's not that they need more braking power but rather the only alternative is rim brakes. On a mountain bike, it's not at all uncommon for rims to bend or come out of true from the beating they take. A bent rim with rim brakes means you now have diminished braking abilties. with a disc system, it's nothing to worry about. Motorcycles used drum brakes rather than rim brakes because weight isnt as important. A drum big enough to not overheat would simply be too heavy for a mountain bike.
They are necessary for any bike that will be ridden on serious terrain. but not for the reason you're assuming. It's not that they need more braking power but rather the only alternative is rim brakes. On a mountain bike, it's not at all uncommon for rims to bend or come out of true from the beating they take. A bent rim with rim brakes means you now have diminished braking abilties. with a disc system, it's nothing to worry about. Motorcycles used drum brakes rather than rim brakes because weight isnt as important. A drum big enough to not overheat would simply be too heavy for a mountain bike.
front/back are required but they don't have to be disc brakes
front/back are required but they don't have to be disc brakes
