Performance Friction’s Killer BMW 135i Brake System. Track Tested, Street Durable!


Performance Friction’s Killer BMW 135i Brake System
Braided steel brake lines resist swelling under pressure which results in a firmer more positive brake pedal.  You can really feel a difference when compared to stock rubber brake lines.

The calipers are shape optimized though Finite Element Analysis or FEA, enabling the best combination of light weight and the factor all important for pedal feel, stiffness.  Careful design using FEA also enables the calipers to have the lowest possible profile both radially and axially for wheel clearance flexibility.  The calipers have some very interesting design innovations that provide a high level of performance for not just their race systems but their street kits as well.  The most interesting feature is the use of 4 small brake pads per caliper–one for each piston.  This “Multi-pad” Caliper prevents taper wear of the pads. The small independent pads and pistons ensure nearly equal hydraulic and braking force distribution, not only on the brake pads but throughout the caliper body as well.  This enables the caliper body to be pared down without sacrificing stiffness. The 4 smaller pads also have 4 leading edges, important because the leading edge of any pad produces the greater part of braking force due to the tipping moment created as the brakes are applied.  This gives greater bite than conventional calipers and pads.

Performance Friction’s Killer BMW 135i Brake System
Here are the brake lines in place on the car.  The 90 degree banjo fitting helps position the brake line so it won’t rub on anything.

The 355 mm rotors are made with heat treated high carbon iron alloyed with copper and molybdenum for heat resistance.  The rotors are ventilated with the vent locations and geometry determined by extensive computer aided airflow, stress and thermal analysis.  The rotor’s axial and radial runout are closely controlled to a few ten thousandths of an inch to ensure nearly perfect balance. The rotor’s inner and outer rotor diameters are also machined to within a few ten thousandths of an inch to improve balance as well.  The rotors are fully floated using Performance Friction’s Direct Drive system to reduce stress on the hats and the rotors themselves when hot.  Floating the rotors reduces caliper piston knock back under spindle flex.  A unique and innovative feature of the rotors is that the rotor to hat interface uses a lug system that takes the shear load off of the hat bolts and increases the bearing area so that the rotor float is freer from bind under brake torque load. The rear brake hat is designed to retain the BMW’s factory integral drum rear parking brake while also still retaining this full floating direct drive feature.

Performance Friction’s Killer BMW 135i Brake System
This adapter converts the ear style OEM mounting points to race style radial mounting.  The adapters are billet aluminum.  Radial mounting makes it easier to design a stiffer caliper.

The brake kits comes with all of the radial mount caliper adaptor brackets and swell resisting braided steel brake lines to make installation easy.

Performance Friction’s Killer BMW 135i Brake System
Unlike us, Brian actually reads the instructions.  This is a good habit.

On the BMW, driver Mike Bonanni reported that the Performance Friction system has superior feel, excellent fade resistance and really good balance compared to the stock brakes and the previous upgraded brake system that the car had.  Unfortunately, on the car’s first track outing with the new brakes, it rained.  At the following event, the Redline Time Attack season finale, the Berk car suffered from electronic gremlins and never completed a full lap at speed, preventing us from using our data system to record brake system data and video.

Performance Friction’s Killer BMW 135i Brake System
Our awesome front brakes!  We bled the system with Motul RBF 660 brake fluid when we were done.

Look for us to have a more complete test evaluation of the Performance Friction brake system sometime in the near future.


Performance Friction
Berk Technology

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