Brake Proportioning Valves

A brake proportioning valve is a great way to adjust front-to-rear brake bias in cars where the rules require the use of an OEM dual-circuit master cylinder. The valve gets installed in the rear brake line to reduce the pressure at the rear brakes under heavy braking.

Lever Type valves use a lever handle to select from several (usually 7) distinct settings. This provides excellent repeatability, at the expense of fine adjustment.
Knob Style (also called Screw Type) allow virtually unlimited adjustment throughout the range, but because there are no detents it can be difficult to get back to a previous setting.