CBS or Combined Braking System is a combined braking system whereby when one brake lever is pressed it activates both brakes. Generally when the bike is at high speed it becomes very dangerous to stop the bike by pressing a brake. Because in this case, there is a possibility that the wheel will jam and the bike will overturn. That is why it is very important to have a balance between the hand and foot brakes. If a bike has a CBS system then both brakes will work together at a certain rate no matter which brake is pressed.