Braking is not discussed much in dirt-track racing, despite being an important skill required to be a successful racer. Most racers are content to simply have a decent master cylinder and adjustable brake bias. While it is other components in the system that generate the binding pressure, for PFC Brakes it is the brake pad itself that is one of the more important pieces of the brake system.
James Borner, a design engineer at Performance Friction Corporation (PFC Brakes) once explained brakes as having three phases. “You have your initial application of the brakes and then the applied deceleration of the race car over a given distance,” Borner said. “The third phase is the characteristics of the brake release as you accelerate. That is the most important in my view. This third phase determines how quickly you go from braking and generating friction, to being drag-free so your power can go back into accelerating the vehicle forward.
The transition from braking to accelerating is extremely important… – James Borner
“The transition from braking to accelerating is extremely important, especially where you’re trying to gain an advantage when accelerating out of a corner. More often than not, this acceleration point is where passing occurs.”
With so many different available brake pad options for the dirt-track market these days, there is also a lot of confusion about brake pads and the pad material. According to Chris Dilbeck, PRC Brakes’ NASCAR and short track sales manager, “The biggest thing is going from one type of dirt car to another type of dirt car, things don’t translate as easily as we’d all like it to.
“There are so many types of calipers, so many different types of discs, so many different types of brake packages,” Dilbeck says, adding; “From a Crate Late Model to a Super Late Model, to a Dirt Modified, There are big differences between them. A Sprint Car gets even more convoluted because you have a titanium rotor to deal with. It gets even more interesting there!”
We love “interesting” as much as anyone else, but for this article, we are going to focus on what many would call “fendered cars” or “door cars” and not the Sprint Cars. However, you can look forward to a future article that is dedicated to Sprint Car brakes.
Dealing With Fender Cars
Once referred to as “taxi cabs on dirt,” stock cars and late models have become pillars in many dirt-track promoter’s racing programs. When it comes to these classes of race cars, PFC Brakes has built up an amazing portfolio of experience in its more than 35 years of circle track racing. Starting with its patented brake pads, the PFC Brakes team chalked up their first win at Martinsville, in April of 1985. They have since expanded the product line to include rotors and calipers, catering mainly to circle track and road-racing enthusiasts.
We followed up with Dilbeck on its dirt circle track brake pads. “For fender cars, you have a Dynalite caliper-style and a Superlite caliper-style, both having different pad volumes,” he says. “The brake pad is going to perform differently for those two types of pad packages. You can’t just look at ‘hey this guy is using a PFC 97 compound that is really cool. I can put them on my brake package and they are going to do the same thing for me,’ It is not always an apples-to-apples comparison.”
When you cannot rely on a “monkey-see, monkey-do” approach, how can you evaluate what pad is best for you? “It’s almost one of those things where you really have to look at the brake package as a whole,” states Dilbeck. “Then make your brake pad compound selection from that.”
There are other factors that weigh into pad selection as well, and many racers will need to find help. “Unless you are somebody that races every weekend or somebody that has a feel for what they need, it is better to listen to the brake company and find the shoe to fit you – select a brake-pad compound just like you would a pair of shoes. Size is different compared to the brand and fit is different for each brand. For brake pads, you have to find the one that fits you as a driver, the one that fits the race track where you run,” Dilbeck advises.
At OneDirt, we’ve always been fans of using different components that have been tested together. We asked Dilbeck about this principal. “We like it because we are the only brake company that builds a full line of brake components. It keeps things a lot simpler. Similar materials are being used every time. It’s just one less variable you don’t have to worry about when you change brands between your pads and calipers.”
“Let’s say you bought a new disc and a new pad. On the dirt side, you don’t have time to do a bedding-in period. You have to be ready to go on the track for hot laps when they call you. That is just a luxury you don’t have. He continues, “With asphalt, you have time to go out on the track and bed-in your brakes. On dirt, it’s gotta be ready to go for that five-lap hot-lap session.”
You really need to keep a brake pad that was bedded with that disc if at all possible. – Chris Dilbeck
This compresses the time drivers have to determine what brake pads they need for the event. The set they start with may not feel correct and a quick pad change in the pits is required. Dilbeck has a warning about swapping pads on the fly: “You really need to keep a brake pad that was bedded with that disc if at all possible.”
When it comes to manufacturing brake pads, there are several things that each company does differently with each pad compound. Some pads have lubricants that are built into the pads and/or different materials that are incorporated in the pads to keep the disc from overheating where other compounds won’t.
“There are certain pad compounds we work with a lot more often,” Dilbeck states. “We know which PFC Brake pads will work on top of other brand rotors because we’ve tested them on our dyno. We know that they will work together. Many times, when you change brake pads, you need to put on a fresh disc too.”
According to Dilbeck, having just one specific pad compound is difficult in the dirt market. This is due to the different levels of driving styles, the number of brake calipers on the market, and the different race tracks. “It’s really difficult to have just one compound.”
How To Choose A Good Pad To Start With
When looking for a starting point, Dilbeck recommends talking to the chassis builder or your crew chief. “Start with their opinion about what brake pads to run on which tracks. Then contact someone like me at PFC Brakes — or whatever brand you use — and consult with them. We can generally put you in the right direction for what brake package to go with.”
If it all seems too complicated, just call the brake pad manufacturer. “We can consult with your chassis builder or setup person and help build-up that notebook about the brakes so that we can get the right brake package for a specific racer,” Dilbeck added.
“I’m a racer, but I only get to race four or five times a year. If I can help one of our customers get into the Winner’s Circle, then I feel a sense of accomplishment.”
Lastly, Dilbeck offers a tip on rotor selection. “We recommend using a full-face disc and not the scallop-type disc. You are better off having that full contact disc than a flower-shaped surface and a flat plane pad.”
Anyone needing more information on brake-pad selection for dirt oval racing can call Chris Dilbeck directly at 803-370-0681, or visit the company at PFC Brakes.