Brakes are required to stop the vehicle within the smallest possible distance & this is done by converting the kinetic energy of the vehicle into the heat energy which is dissipated into the atmosphere.

Requirement of braking system:
i) The brakes must the strong enough to stop the vehicle within a minimum distance in an emergency. But this should also be consistent with safety.
ii) The brakes must have good antifade characteristics i.e, their effectiveness should not decrease with constant, prolonged application e.g while descending hills. This requirements demands that coding of the brakes should be very efficient

Disc Brake:
Friction pads are flat.
Friction surface directly exposed to air cooling.
More efficiency.
Light in weight.
Better & anti fade characteristics
Frictional area of pad is less.

Drum Brake:
Friction lining are curved shape.
Friction occur internally & heat dissipate by conduction & convection.
Loss of efficiency.
Heavier in weight.
Poor anti fade characteristics.
Frictional area of pad is made.