The ST40 rear caliper also has differential piston sizing, high-temperature dust boots, stainless steel pad abutments and extensive lightening milling on the bottom side of the forging as well.
The rear rotors are very much like the front, except they have a smaller 335mm diameter and are more narrow at 28mm instead of 32mm.
Since the 987 has a drum parking brake contained within the rotor, the Stoptech Aerorotor has a drum machined into the rear hat. Since the drum is aluminum, you can’t really go around doing e-brake initiations in drifting all the time but it will work fine as a parking brake or for an emergency stop if for some reason you have a complete brake failure. This hat saves a lot of weight over stock. In fact, our brakes are light, even though they are much bigger, our front brakes weigh about the same as stock and our rear brakes save about 3 lbs per axle.
Our Stoptech brakes came with braided steel lines. These Teflon lined hoses resist swelling with pressure and offer improved pedal feel. Stoptech hoses are also DOT approved and pass the tough whip test, not that that matters that much for a race car but they are fully street legal. For the 987, the kit also comes with a line for the brake pad wear sensor. For brake pads, we are using the 309 compound. This is a high-performance pad compound that is streetable and won’t chew up the rotors at low temperatures. The new pads have much more surface area than stock.
The new Stoptech rotors absolutely dwarf the stock Brembo rotors.