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Brakes » Brake Proportioning & Pressure Valves

Brake Proportioning Valves & Pressure Valves

What is a proportioning valve?

A proportioning valve is a pressure reduction device used to adjust and tune brake bias. It is typically installed in-line in the rear brake line to reduce rear braking efficiency and compensate for premature rear-wheel lock-up; a result of incorrect front to rear brake bias. An adjustable proportioning valve permits incremental adjustments to fine tune brake bias. This ability to adjust front-rear brake bias is particularly important in race applications, as changing track conditions and vehicle dynamics usually require the brake bias be adjusted throughout the race.


What is brake bias?

Brake bias is the percentage of total braking force applied to the front wheels. It can also be called brake balance.  A 60-70% bias is common on RWD street vehicles, applying 60-70% of the total braking force to the front brakes. Front wheel drive cars can have up to 80% brake bias.