There is a substantial amount of engineering that goes into designing the right rotor and brake pad combination. Power Stop is one of the first companies in North America to specialize in providing better then OE braking. What distinguishes Power Stop from most of our competitors is our ability to supply a brake rotor and pad kit that is designed specifically for your vehicle and driving profile. For a complete listing of brake solutions by vehicle type and driving profile, go to our website home page and click on “Application Guide”.

Some trucks and SUV’s can top 13,000 lbs. High gross vehicle weight means more kinetic energy that must be converted to heat as you stop. For example, a typical Excursion is 9600 pounds. Stopping this SUV at 70 mph requires the same energy as dropping it from a 16 story building. Now imagine taking this amount of energy and converting it into heat over 5 seconds. That is a lot of heat! So when stopping at high speeds, conventional rotors and pads can achieve a red hot 1000 degrees Fahrenheit. When brake pads get hot, bad things start to happen like brake fade, pad glazing and “rotor warping”.

Brake Fade:
At high temperatures, brake pads start to break down and lose pad bite. This is called brake fade, and it happens with most conventional brake pads under extreme braking conditions. Trucks and SUV’s, are more susceptible to brake fade. That is why there are truck pull-off areas on the downhill side of mountains, and also why there are warning signs to check your brakes before going into the toll plaza. Dynamometer tests such as SAE J2430 or ISO NWI 26867 have sections devoted to brake fade. The graphs below show samples of fade tests performed by an independent lab.

Pad Glazing:
Heat can cause pads to leave thin resin deposits on the rotor surface. Resin is used as a binding agent for the various friction materials in the pad. It is the glue that holds it all together. The resin can turn to liquid and start glazing on the rotor. Some of the common effects of glazing are “warped rotors”, reduced stopping power, and brake judder. The SAE paper 2006-01-0691 “The Effect of Rotor Cross-drilling on Brake Performance” authored by two GM engineers concluded that cross drilled rotors can eliminate pad glazing.

Rotor Warping:
Rotor warping is a misnomer. Hot rotors can cause some coning of the flange but they do not typically warp. People use this term to describe pulsating brakes (what engineers call brake judder). So I reluctantly use the term “rotor warping” but it is really hot spots that are forming in the iron rotor. Uneven friction layer deposition is the culprit. Friction deposits leave a high spot on the rotor. As the pad rubs against these high spots, it gets hotter than other parts of the rotor. At more than 1100 degrees the metallurgy can change to form hard nodules called cementite. These spots are harder than the surrounding rotor material and tend not to wear down. So they become elevated as the rotor wears and then you start to feel pedal pulsation. You can try to turn down the rotors, but it often comes back because the nodules of cementite extend farther than the cut. You can prevent this by using cross drilled rotors (not slotted rotors) that cool the brakes up to 180 degrees. As you may know, slotted rotors do not affect brake temperature so it is not a good solution for high temperature brake fade.

The Power Stop solution:
If you own a truck or SUV up to 1 ton, Power Stop recommends that you

Cryo Rotors:
In certain applications we also suggest cryogenically treated brake rotors. Cryo rotors extend rotor life. Power Stop also heat treats the rotors after they are cooled to -300 Fahrenheit to stress relieve them. The testing from Controlled Thermo shows reduced stress risers from the cryogenic treatment. This means that cryo treated rotors are less susceptible to thermally induced failure.

Test Data:
The graphs show examples of brake fade. The green lines with the black dots are the coefficient of friction (mu). The test uses a Chevy Tahoe front brake. The ISO NWI 2560 test shows 15 consecutive stops where the temperature increases after each stop. If mu drops as the temperature rises, then the pads lose pad bite (i.e. brake fade). Z36 pads hold at .35 mu vs .3 mu for the OEM pad. Power Stop offers almost 20% more braking power than the OE pad and much better than competitors.

Coefficient of friction .3

Coefficient of friction .25

Several brands of brake pads that we tested suffered substantial brake fade where the friction coefficient dropped to .15 mu. Brake pads from different suppliers can have a coefficient of friction (mu) that is 50% less than the OEM pad. Sometimes the only way you find out about this is when you have a panic stop or you are coming down a steep hill and experience brake fade. It is a scary feeling to lose brake power. Power Stop Z36 Truck and Tow pads provide 20% more brake torque than the OE pad for safe, consistent stops.

To achieve maximum braking power, we suggest combining our Z36 Truck and Tow pads with drilled rotors.