Tech Corner with Bill Cummings

Q: What is brake bias? Why is it important?

A: Brake bias is the distribution of a vehicles braking power between the front and rear wheels.

Under full deceleration, a certain amount of a vehicle's weight is transferred from the rear to the front. Due to this transfer, you would need stronger brakes in the front of the vehicle than you would need in the rear. The percentage of braking that you have in the front compared to the rear is called brake bias.

Here's an example to better explain what happens under full deceleration. A 3000 lb vehicle has a 50/50 weight distribution. This means there is 1500 lbs over each axle when it is not in motion. When you are driving it and apply the brakes, half of the weight over the rear axle will be transferred to the front axle, resulting in 2250 lbs over the front axle and 750 lbs over the rear axle. In this instance, you would have a brake bias of 75/25 (75% of the weight is over the front axle and 25% is over the rear axle). At the same time, you would want your braking to match with 75% of the braking power in the front and 25% in the rear.

There are many ways to adjust the brake bias other than changing your caliper and rotor sizes. You can adjust your brake bias hydraulically by installing an adjustable proportioning valve to reduce the amount of pressure going to the rear brake system. The adjustable valve cannot be used on every vehicle. You can contact SSBC to see if this is applicable for your vehicle.

Another way to change the brake bias is to change the type of brake pad compound you are using. A more aggressive pad in the front system than in the rear system will increase your braking power in the front system.

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