Automotive Brake Calculator


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Coefficient of friction (µ) of brake pads. Ask your supplier or look on the internet for specific data. Numbers can range from as low as 0.2 for some street pads, all the way up to 0.7or even higher, for use on some very fast race cars with lots of down force. Manufacturers have more exact numbers for you, usually in the form of a µ vs. temp. graph, but as an indication, street pads range roughly from 0.2 - 0.4 and race pads from 0.4 - 0.6.

When looking at the "µ vs. temp. graph" of the brake pads of your choice, estimate or calculate the average value of µ for the temperature range your brake pads will be operating in and use that number in the calculator.


Note that the size of the brake pads does not matter. A larger brake pad applies the same force (coming from the piston(s) behind it) as a smaller pad, but it does so against a larger area of the rotor which reduces the pressure (pressure = force / area). The only factors that determine the Friction Force between pads and rotor are µ and Normal Force (force perpendicular to back of brake pads).

Braking with bigger pads will spread the heat (kinetic energy of the vehicle-mass moving with a certain speed, converted into heat by means of friction) over a larger surface area of friction material and therefore bigger brake pads will run "cooler" and will usually show less wear as a result (everything else being equal).


Last Update: 01/01/2017
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