How to Calculate Brake Efficiency

by Cecelia Owens

The brake efficiency, which is expressed as a percentage, calculates how effective your brakes are when you lightly and heavily tap on them, according to the "M.O.T Inspection Manual." The brakes' efficiency is dependent on the weight of your vehicle and the force of your brakes. Learning how to calculate brake efficiency can help you figure out if your brakes are functioning normally or need to be changed. Strong brakes in rough elements, such as snow and rain can help prevent a potentially fatal accident.

Calculate your car's total brake effort, which can only be done at a mechanic shop. The total braking effort equals the effort it takes to stop your car when you press your floor brake. The testing is done on a tire machine that automatically rotates your tires, and then suddenly stops them. It simulates the actual stop and go of a car. Ask your mechanic to test the car on the tire machine and they can give you a total braking effort calculation.

Calculate the vehicle's weight. The weight of the vehicle can be found in the vehicle's manual.

Divide the vehicle's weight by the total brake effort, and then multiply the number by 100 to get the brake efficiency percentage.


  • Weigh everything inside your car as well, because that will affect the brakes.

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