Brake Bias Calculator
Calculate the front/rear brake bias percentage from master cylinder bore sizes and caliper piston areas to optimize braking balance for performance or track use.
Results
What is it?
Brake bias is the proportion of total braking force applied to the front versus rear axle. During hard braking, weight transfers forward, increasing front tire grip. Optimal bias matches this weight transfer � typically 60�70% front for road cars. Too much rear bias causes oversteer (rear lockup); too little causes understeer and front lockup.
How to use
Enter the master cylinder bore diameters (front and rear circuits in a dual-circuit system or balance bar setup) and the total caliper piston area for each axle (sum of all piston areas on that axle). The bias calculation computes hydraulic force multiplication through the entire circuit.
Example scenario
Front MC bore 25.4 mm (area 507 mm2) driving 60 cm2 calipers = force factor 30,420. Rear MC bore 22.2 mm (area 387 mm2) driving 35 cm2 calipers = force factor 13,548. Front bias = 30,420 / (30,420 + 13,548) = 69.2% � well-balanced for a performance road car.
Pro tip
On track cars with an adjustable brake bias bar, target 58�65% front bias as a starting point and adjust based on driver feedback. A driver experiencing rear lockup should increase front bias (move bar forward). Install brake bias adjustment accessible from the cockpit so the driver can fine-tune between sessions as fuel load and tire wear change balance.