How to Choose Disc Brake Pads
by Ray Gorman ,SSBC
Once you dig into the world of performance brake pads, you will find a bewildering array of compounds with different materials, wear ratings, friction values, and temperature ranges. Companies like, Hawk Performance, Performance friction make brake pads for very specific performance levels, both street and race. Even OE-replacement manufacturers like Bendix and Raybestos offer pads tailored for everything from Grandma's go-to-church-on Sunday sedan to high performance sports and muscle cars.
In this article, we'll explain the basics of disc brake pad materials, how to choose a pad based on intended use, and the proper procedure for bedding in those new pads.
Brake Pad Materials
A disc brake pad is a simple thing, composed of a formed pad of friction material on a steel backing plate. The composition of the friction material is one part science and one part black art. Some pad manufacturers have more than 50 different compounds tailored for specific uses-and those compound formulas are more top secret than the alien spaceships the government says it doesn't have over in Area 51.
Back in the good old days, manufacturers used asbestos to bind the friction compound materials together. It resisted high temperatures, and the barb-like composition of asbestos fibers held the friction material together quite well. When asbestos was phased out back in
the early 1990s, pad makers went looking for a new material. The industry settled on three types-non-asbestos organic, semi-metallic, and ceramic. When you see a brake pad advertised as metallic or ceramic, for example, they're really talking about the binder that holds the friction material together.
Organic pads have a non-asbestos organic friction/binder material; the pads must have less than 20% metallic content to be labeled organic. The main benefits of quality organic pad are quiet operation and longer rotor life. Because they are not as hard as semi-metallic pads, organic pads typically do not last as long and don't perform as well in high temperature applications like towing or racing. Many standard brake pad series are high-quality organic street formulations that offer stopping performance on-par with semi-metallic pads without the metal-to-metal contact and accompanying rotor wear. They are limited to daily driving and are not recommended for every vehicle.
Semi-metallic pads are made of a hard resin matrix with steel fibers added to increase hardness and prolong pad life. It's probably the most common pad available-most cars and light trucks on the road use semi-metallic pads. One big advantage of a metallic pad is improved high temperature performance; its grip actually increases as the pad warms up to operating temperature. That makes semi-metallic’s ideal for heavy- duty use (high performance street, towing, etc.) and racing, especially circle track and road racing. A downside to semi-metallic’s is noise-the pads' hardness and steel fibers increase metal-to-metal contact with the rotors, and tend to magnify noise-producing vibrations rather than dampen them. There are special shims that are mounted to the back of the pad which will help in reducing noise or groan. Many new vehicles have special tapers on the front and rear of the pads to reduce vehicle groan.
Ceramic pads are the latest type on the disc brake scene. As the name implies, the friction material contains ceramic fibers as part of the binder. Ceramic is a good choice for the street because it offers stable, predictable friction characteristics, especially at lower
temperatures. Ceramic pads also provide a consistent pedal feel that is unaffected by hot or cold (unlike semi-metallic pads, ceramic's coefficient of friction does not drop off as quickly when the temperature changes). Ceramic pads are quieter than semi-metallic and organic pads, and generate low amounts of light-colored brake dust so it isn't as noticeable on your wheels. The down fall of this type of pad, it does not have the initial bite and grab.
So which type of pad is the right one for your application? If you are looking for stock replacement pads on a street-driven vehicle, stick to the type specified by the factory. If your truck came with semi-metallic pads, for example, use semi-metallic replacement pads to maintain proper braking performance.
Fortunately, there is no problem upgrading to performance-oriented brake pads. You can safely switch from organics to semi-metallic or ceramic pads, or go from semi-metallic to ceramic and vice-versa. Upgrading your pads will help decrease stopping distances and improve pedal feel-and make you safer.
Here is a general guideline to help you choose the right type of pad:
Semi-Metallic Pads
• High-horsepower street cars
• Tow vehicles and heavy-duty hauling (passengers or cargo)
• Racing, especially circle track and road racing
• Severe-duty applications that generate high brake temperatures (hilly/mountainous terrain, city or other heavy stop/go driving, etc.)
Ceramic Pads
• Daily-driven vehicles
• Performance-oriented, street-driven vehicles
• Applications where improved pedal feel, longer rotor life, and low noise/low dust are important
A rule of thumb: when shopping for pads, stick with proven brands. This is especially important when choosing pads for racing or towing, where brake failure can lead to disaster very quickly. Choosing a quality name brand is especially important when buying ceramic brake pads. There is currently no standard defining how much ceramic material a pad must have to qualify as a “true" ceramic. Some pads labeled as ceramic may contain very little of the stuff and will not perform as desired. High-quality brands may cost more, but you will get the performance you're paying for.
Temperature Matters
Choosing a brake pad for a race car is a more involved than choosing a pad for a street-driven vehicle. The pads must be able to function at the temperatures reached on the track; in other words, the brakes should not fade at operating temperatures. We recommend, pad compounds rated for temperatures of 1,000 degrees Fahrenheit and up are usually necessary for most asphalt circle and road race applications. Dirt track, drag racing, and high-horsepower street performance applications can use pads rated at temperatures between 500 and 1,000 degrees Fahrenheit.
Keep in mind that these are general recommendations, not absolute values. Things like track length, brake cooling (airflow to the brakes), weather, and tire selection can affect brake temperatures. Like any other upgrade, the best way to find the right brake pad is run 'em at the track. You might have to go through a couple sets to find the pad that provides the best overall performance. Fortunately, SSBC and other performance brake companies offer a wide range of pad formulations to help make your selection chores easier.
We hope this brake pad primer gives you a better idea on what types of disc brake pads are available, what each is best for, and how to break them in for optimum performance. Of course, you can get more information by talking with your SSBC dealer, Lenny Schaeffer at Chop-Shop Customs.
