Start / Terms / Rear Brake Caliper Piston 1 Diameter
The rear brake caliper piston 1 diameter is the diameter of the first, or only, piston in each brake caliper or brake caliper half.
Even if the rear brake calipers have pistons on both sides of the brake rotor, the diameter(s) are only entered for one side. So, for a two-piston caliper, only one piston diameter is entered. For a four-piston caliper, only two diameters are entered. And for a six-piston caliper, only 3 piston diameters are entered.