Some consumers may think brake pads are a generic product and are pretty much all the same, but nothing could be further from the truth. A wide variety of different friction materials may be used in brake pads to change their friction, noise, wear, pedal feel, dusting and braking characteristics. Though some friction materials are suitable for a broad range of applications, many are formulated for a specific year, make and model of vehicle.
A large, full-size SUV obviously has different braking requirements than a small economy car. Likewise, a performance car will require a more heat- and wear-resistant type of friction material than your average daily driver. Brake suppliers know this and often go to great lengths to make sure the pads in their product line are a close match for the vehicles they fit.
All brake pads have two-letter edge codes for the hot and cold friction ratings of the material. Unfortunately, edge codes don’t reveal much about the actual performance characteristics of the pads because that can vary quite a bit depending on the other ingredients and even the design of the pads. Two pads that may have similar edge code ratings may have very different noise, braking and wear resistance characteristics.
Ingredients that may be used in a friction material include “ceramic” or “semi-metallic” or “nonasbestos organic” (NAO) fibers. Just as there are many kinds of ceramic materials, so there are different NAO materials. Semi-metallic usually includes chopped steel fibers, buy may include a mix of other metallic fibers including copper for heat dissipation.
Copper is one of the ingredients that will be going away in the future. Some pads are already copper-free and have been for many years. California and Washington have passed laws calling for a phase-out of copper and other materials from brake pads, with compliancy labeling of product packaging to start January 2014. Compliancy levels will include A, B and N edge code ratings, with N having the lowest content of copper as well as asbestos and heavy metals such as chromium, lead, mercury and cadmium. The ratings are being certified by the Automotive Manufacturers Equipment Compliance Agency (AMECA).
The actual ingredients in a friction material are not as important as how the friction material actually performs. According to one J.D. Power survey, the most important features that brake customers want are stopping power, firm pedal feel, quiet operation, no brake pedal pulsations and durability.
Most premium-quality brake pads have all of these qualities and will generally provide a better braking experience than economy or even standard pads. Follow your friction supplier’s application recommendations for the best results.