Brake Pad Selection

We stop our cars by rubbing some mysterious friction material against a piece of steel called a rotor (or drum). This friction creates heat and our cars slow down. The friction material is a huge factor in determining how our car is going to stop. The problem is that the variety of friction materials are almost unlimited. . If there were such a thing as a best brake pad then Pagid and Hawk wouldn’t have to create dozens of different brake compounds. Even if we had a huge test budget (which most of don’t have) we could never test all of the various brake pad material available to us.

The brake pad companies can guide us through their maze of various compounds. We have to be prepared though to answer a few questions. Pagid, Hawk and Carbotech can help you select the best pad for your use but you have to be prepared to help them. They can’t do it without your input.

The good news is that you’re buying race pads and shoes. You only care about stopping. You don’t care about how much brake dust lands on your wheels and you don’t mind if your brakes squeal. If you actually worry about dust and noise then you shouldn’t be shopping for racing brakes. Just head down to your local AutoZone and buy some street pads. You’re not a racer.

Wear: This is pretty much irrelevant for most vintage racers. If you start the weekend with a new set of pads it’s almost impossible to wear them out by Sunday afternoon.

The real issue here is cost. When racers ask about how fast the pads will wear they’re really asking, “How soon will I have to buy new pads?” This is followed by the obvious question regarding rotors. “How long will my rotors last with these pads?” Is rotor wear an issue for you? If it is make sure you let the people at the brake pad company know this.

Weight: The brake folks want to know how much your car actually weighs. They don’t care about what you fill in on the tech sheet. If you have a 1,600 lb. 911 tell them the truth. Weight is mass. It’s just one more factor that has to be considered when picking a brake pad compound.

If you’ve stripped a lot of weight out of your car it’s going to be faster. A lighter car will accelerate faster which means you’re attaining a higher top speed on the straights. There is constant interaction between speed and mass. That’s going to affect your compound choice.

Temperature: You need to know how hot things get. You don’t need a lot of precision here. Anything within a couple hundred degrees will help the brake people. There are two very easy ways to measure brake temperatures. You can use thermal paint on the brake rotors or you can use temperature strips on the calipers. Temperature strips on the caliper are easier to read than rotor paint. The brake pad companies can though work with either number. 

Brake Bias: Checking the brake rotor temperatures with an infrared scan gun is a quick way to check on brake bias. There will be a temperature difference between the front and rear brake rotors. You need to know how great that difference is. Make sure you do this quickly since brake rotors cool down rather rapidly. Write these numbers down so you can give them to the brake pad folks.

There is no rule that says you have to run the same pad compound on both ends of the car. Mixing and matching pad compounds is fairly common. The brake pad company is going to ask you if you’re running a lot of rear brake.  Be ready to answer this question.

How do you actually use the pedal? Everyone thinks they’re braking properly. If you talk to driving instructors and brake manufacturers they feel that most folks are pretty bad at braking. Without getting into a long discussion it seems that most of us spend entirely too much time on the brake pedal. That has a real impact on the type of brake pad you need. Be honest with the brake pad folks when discussing your braking ability.

What tracks do you run on? I’m still looking for a track that doesn’t require hard braking but that may be a personal problem. I do know that coming into turn 17 at Sebring I use a lot of brake. I’m coming down from top speed and turning right. At that point I’m over 1400⁰.

         

The type of pavement is also a factor that the brake company needs to know about. Most companies use different compounds for dirt than they do for asphalt.  Very few vintage events are held on dirt but we do race on asphalt and concrete. At Sebring we race on about six different types of pavement on every lap.

The distance between stops will have an impact on the amount of heat retained in your brakes. If your home track is composed of tight turns with small straights you’re going to encounter a lot of heat build up. A long flowing track with big sweepers (Willow Springs) will be pretty easy on the brakes.

When you factor in all of these things it means you’re probably going to need a different type of brake pad from the guy pitted next to you. This is why the question “What is the best brake pad” is rather silly. The only folks who can really help you are the people who make the pads. And, they can only help you if you know about your car and driving habits.