StopTech's Balanced Brake System Philosophy

StopTech places tremendous emphasis on the concept of a balanced brake system. While they have several patents related to rotor cooling and caliper stiffness, what sets StopTech apart from other big brake companies is their dedication to preserving the factory balance. As the chart below indicates, a brake kit with too much rear bias not only results in longer stopping distances, but is unstable without the assistance of electronic stabilization control or ABS. I can relate to this with my road race car which has an adjustable proportioning valve. The handling gets pretty scary when I've got too much hydraulic pressure going to the rear brakes.

Stopping distance vs. front/rear brake bias (Audi S4 data)


If the brakes are too front biased, the front brakes tend to lock up prematurely and the stopping distances become longer, both with and without ABS. StopTech controls the bias of their kits by retaining the stock master cylinder and juggling caliper piston and rotor sizes to recreate the factory brake torque balance.

The Audi S4 kit was used to generate the numbers for the chart above. StopTech makes 3 different kits for that car, all of which are better balanced than even the factory brakes. You can see that an Audi S4 kit using the Brembo F50 caliper and a 355mm diameter rotor would be front biased due to the larger piston sizes used in that caliper. The same caliper on a 332mm rotor isn't quite as bad and produces the counterintuitive result of shorter stopping distances than the same kit with bigger rotors! A Porsche "Big Red" conversion that uses adapter brackets to attach Porsche 993TT front and rear calipers and rotors to the Audi S4 is rear biased and not only has a longer stopping distance, but it might even be somewhat unstable during hard stops if ABS is disabled.

By careful selection of caliper piston sizes and exhaustive track testing (as you'll see below), StopTech has the potential to yield the shortest stopping distances of any aftermarket brake kit, combined with safe and stable handling.

Next, the driver makes a run at the skid pad at 46.5mph. Partway through the turn, he locks up the brakes and the car comes to a stop. A tape measure is then laid out between the calibrated dots nearest where the car stopped. Then, a measurement is taken from each wheel to that tape with the measurement taken along the line of sight from the wheel to a calibrated reference point. The distance from wheel to tape is recorded as is the distances from the dots and this is all entered into a laptop. Car wheelbase and track is also entered. The laptop does some crunching of numbers and comes up with the "departure angle" of the car from the intended direction. If it is outside of a narrow range, the brake system needs to be rebalanced with either larger or smaller pistons in the front or rear calipers.