Drag racing is all about trying to go fast, which is awesome, but at the end of a run you need to stop, and sometimes you need to do it in a hurry. The right brake pads are essential for a drag racing application if you want the best performance and stopping power. We talk with TBM Brakes, Strange Engineering, and Mark Williams Enterprises about what to need to look for when selecting drag racing brake pads.
Brake pads that are used in drag racing are going to have different characteristics than virtually any other type of pads. Drag racers aren’t worried about how often the brakes are used, they’re focused on the brakes being able to hold the car at the starting line, being accurate if they need to work the stripe, and they need to slow the car down after it reaches terminal speed. This means the pads used in drag racing will consist of a different type of compound and will have a different life cycle than what’s on your road car.
Drag Racing Brake Pad Materials
Brake pads are comprised of an array of materials that vary depending on the application and the makeup of the brake rotors. You’ll find steel, copper, iron, ceramics, other alloys, and fibers in most brake pads. The exact mixture of these is kept confidential by each manufacturer.
Jeff Capek from Strange Engineering explains in more detail what goes into the selection of brake pad materials for drag racing.
“High-performance semi-metallic and full metallic compounds that are made up of proprietary mixtures of different abrasives and powdered metals are what we use. Semi-metallic compounds offer a much higher coefficient of friction and temperature/fade resistance than a typical low-cost replacement organic brake pad. Full metallic compounds offer a significant increase in temperature/fade resistance and high-speed performance with greatly reduced wear compared to semi-metallic.”
Essentially, pads come down to four things: friction coefficient at different temperatures, how durable they are, how hard they are on rotors, and feel. – Andrew Dickson, Mark Williams Enterprises
The material used for the brake pads also has to match the material makeup of the rotors. So, if you’re using a steel rotor your brake pads must also be made of steel, because carbon-fiber pads are only compatible with carbon-fiber rotors. Most drag racing vehicles use steel rotors, so that means you’ll have some choices when it comes to the hardness of the brake pads you will use.
Mark Williams Enterprises has been in the business of helping racecars stop for decades. Here’s what Williams has to say when it comes to the hardmess of brake pads used in drag racing.
“Soft (non-metallic or organic) pads typically are a composition of glass, rubber, Kevlar, and resins,” Williams begins. “These pads grip really well, but also wear out fairly quickly. On the other end of the spectrum are metallic pads that commonly feature a composition of iron, copper, steel, and graphite. These “hard” linings last far longer than their soft counterparts, but also take their toll on the rotors as they require more heat to obtain the necessary friction. It’s not uncommon to find it necessary to change rotors when the pads are replaced.”
Compounds Are Key
Brake pad materials are just the raw ingredients — the compounds that are created from the materials are the most important part of the pad. TBM, Strange, and Mark Williams have done a lot of research into compounds to find what works the best for the unique demands of drag racing.
Jason Smith from TBM breaks down the pad characteristics to look for based on your application.
“Much like anything, with pad compounds, as you start to increase/improve one characteristic, you typically sacrifice something in one of the other characteristics,” Smith explains. “You need to look at the dynamic friction of the material, the operating temperature the material achieves said friction, the temperature ceiling at which the compound starts to lose friction, how well the friction material wears, along with other factors based on your application.”
Drag racing vehicles use their brakes differently than any other motorsport. The brake pads in drag racing need to have compounds that offer good performance at a cool (or rather, not hot) temperature versus the heat that a road racing type of pad requires. If saving weight is important to a drag racer, along with an elevated level of performance, that’s when carbon-fiber pads and rotors become an option.
“Mark Williams Enterprises recommends Ferodo High Friction non-asbestos brake pads for most applications,” Williams says. “This is a semi-metallic brake pad that has excellent stopping power, heat control, and provides the best balance of performance with durability. We’ve had racers try other brands of semi-metallic brake pads, but they come back to the Ferodos pads, as the composition seems to work the best.”
TBM Brakes uses a smaller caliper and rotor that has a reduced diameter, so it’s had to make adjustments to how the braking system functions. This includes the amount of torque needed and line pressure…this, in turn, meant TBM had to fine-tune the brake compounds it uses for drag racing. Out of the many compounds the company has created, its #1, #85, and carbon-fiber pads are most popular for drag racing.
“Our #85 compound has great cold bite and a temperature ceiling of 1500-plus degrees. This is a compound we recommend for extremely fast and/or heavy applications,” smith explains. “The high-temperature ceiling will keep you in the friction longer during an emergency shut down as the rotor gets heat soaked. The sacrifice is that his compound can be extremely abrasive and wear rapidly under low temperatures. So, it should never be used in street driving conditions.”
Smith goes into further detail about TBM’s other brake pad compound for its metallic brake rotors.
“The # 1 compound has good cold friction, remains linear in its torque output all the way to a bit over 1,000 degrees, and wears decent throughout the operating temperature zone. This is a compound that fares well with what I would say as the higher percentage of drag cars out there. It has far better wear characteristics, but you do sacrifice a little bit of friction and a lower temperature ceiling,” Smith states.
As we mentioned earlier carbon-fiber pads have to be used with carbon-fiber rotors. Smith explains when carbon-fiber becomes the best option for brake pads and rotors.
“Carbon-fiber can handle far more heat, so it’s desirable for extremely fast or heavy applications. The downside of carbon-fiber is cost, and the friction can be very inconsistent and unstable at times, especially without a lot of heat. Thus, brake performance and safety can be sacrificed if used on an application that doesn’t generate enough heat.”
Much like anything, with pad compounds, as you start to increase/improve one characteristic, you typically sacrifice something in one of the other characteristics. – Jason Smith, TBM Brakes
Before you select a compound or work with a company to help in the process there will be some information you need to have ready. To get the right compound, the vehicle’s weight, speed, whether it sees any street miles, the distance it will race at, how long the shutdown areas are at tracks you visit, and how often you pull the parachute (if applicable) will be needed. All of these factors play a role in the pads you’ll want to use to avoid any issues.
“We have a chart based on the BTUs generated from a given weight and speed of a vehicle that we use. This helps our customers choose the appropriate compound for their platform. The rotor temperatures of a 3,000-pound car pulling up to a stop sign from 50 mph, shutting down at 160 mph in the 1/8-mile or 200 mph in the 1/4-mile are completely different, thus, may need a different pad. For this example, we would recommend our #1 compound for 1/8-mile racing, and if the owner chooses to take the car out on the street, but would recommend dropping the #85 pads in if they plan on going 1/4-mile racing,” Smith says.
Rotor Compatibility & Brake Pad Maintenance
We’ve established that matching a vehicle’s braking system to its intended use plays a role in the brake pads you’re going to select. But you still need to make sure the rotors and pads are compatible material-wise. If you don’t match the right parts together the braking system won’t work as it should, rotors won’t wear properly, and brake pads will not last.
“A brake pad leaves a transfer layer of material on the brake rotor itself. If a brake pad is changed the transfer layer may cause performance issues due to incompatibility with the new brake compound. Any semi-metallic or full metallic pad can be used on steel, iron, or stainless steel rotors. Carbon-fiber pads and rotors must be matched together — that’s how they’re designed to work and it allows them to function properly. It’s a good idea to keep a similar compound on the same rotor to prevent pulsation or poor performance,” Capek explains.
So, when’s the last time you checked the brake pads on your race car? Drag racing isn’t kind to brakes, it requires them to hold a high-powered car perfectly still on the starting line, then it’s demanding at the top end after a run putting a lot of stress on all the parts, especially the pads. Brake pad maintenance is critical for safety reasons and to ensure the brakes are working their best at all times.
“How often should brake pads be changed? The common rule of thumb employed by our company is to recommend changing pads when they’re about 50-percent worn. You’ll also want to be sure to verify rotor flatness, too. It’s always a good idea to check the brake line pressure because you need 1,000 psi for normal stopping, and 1,200 psi for severe stopping,” Williams says.
Capek adds his thoughts on what Strange Engineering recommends when it comes to brake pad and rotor maintenance for your racecar.
“After you’ve changed brake pads, you might experience performance issues due to the new brake pad compound. The easiest way to remedy this is to resurface the rotors and complete a new bedding cycle. You always need to inspect the friction surface of the pad and the rotor for any heat cracks during maintenance. It’s best to monitor the thickness of your brake pads so you know when to change them. We typically recommend replacing the pads as you approach 1/8-inch of brake material left on the pad.”
Brake pads aren’t the sexiest thing in drag racing, but they are one of the most important safety and performance items racers don’t pay enough attention to. If you take the time to select the right pads, you’ll see better stopping performance, plus, you won’t have to worry about your racecar pushing through the beams on the starting line.