The next time you finish a session on track, take a quick glance at your tires. You will notice an interesting phenomenon. You have added rubber to your tires. This is a bit counterintuitive, since you were just on track driving like a maniac, and you assumed you were losing rubber by wearing down your tires. Sure, you probably did some of that, but what you also did was pick up hot pieces of rubber that were on the track, which cooled and stuck to your tires. This is referred to by racers as OPR — other people’s rubber.
You may ask, “So what? Who cares? I scored some free rubber, maybe my tires will last longer now. What’s the big deal?” In most cases it isn’t a big deal. The next time you go out on track, heat up the tires and really start to drive the car hard, that rubber eventually will fall off the tire and land on the track for someone else to pick up and stick to their tires. However, when that rubber gets hot enough to fall off your tire it might not be at a convenient moment for you on track, like during qualifying when you want your tires at 100 percent optimization.
This extra rubber stuck to your tire — often called marbles, or slag or snakes — is not mated with the rest of the tire to provide you with grip and stability. Instead, this rubber is wobbly and unpredictable. On front-wheel-drive cars, like our Honda Challenge Acura Integra, sometimes we can’t get the rear tires hot enough or have enough weight in the rear of the car to get this extra rubber to go away during warmup laps. When we want the tire to do its job as designed, like at the apex of a corner on a qualifying lap, we don’t want that to be the moment for this extra rubber to let go.
Because our team predominantly competes in front-wheel-drive cars, we have accumulated our fair share of other people’s rubber on our rear tires over the years. We could rotate our rear tires to the front of the car and pretty easily burn off the OPR, but we didn’t want our tire management strategy to be determined based on extra rubber removal. Eventually, we found a solution for this extra rubber problem from racers who compete in autocross.
Believe it or not, road racers actually can learn a lot from autocrossers. One practice, which many autocrossers who compete at the top levels use, is removing OPR from tires between runs. I have seen this done a few different ways. One is to use a heat gun or a small torch to heat the rubber and a hand scraper to remove the rubber. This process is arduous and some people don’t like adding heat cycles to their tires with the heat gun or torch. The other practice, and it is the one we at Double Nickel Nine Motorsports have adopted, is using an oscillating tool.
I scored a Dewalt cordless oscillating tool for $99. It has nice ergonomics and it is easy to use. The battery lasts long enough to remove OPR from numerous tires. I swapped out the cutting blade and replaced it with a scraper to remove OPR from the tires without damaging the base rubber on the tires.
Heat is your friend in this process. If the tire is still warm, the extra rubber comes off pretty easily with the oscillating tool. This is why some people like to use a heat gun or a torch when they are doing this back at the shop after a race weekend.
It is always good to have a friend and a helping hand. If you take the tire off the car to do your OPR removal, then it helps to have someone hold the tire steady and rotate it as you work the rubber off of the tire. If you are back at the shop alone, roll the tire up against a wall to hold it steady.
I also have used oscillating tools that plugged into an outlet for power. The advantage here is you don’t have to worry about battery life, however I found the cord to be limiting in my ability to maneuver the tool around the tire easily. My preference is a battery-powered tool. We also have tried removing OPR by jacking the car up just enough to allow us to rotate the tires and then lying on our backs and working the tool on the tires. I have found this to be not the most fun thing to do in the world and will quickly wear out your arms.
So, let’s recap. Other people’s rubber – OPR — is not what you want on your tires. A cordless oscillating tool with a scraper attachment on a warm tire will remove the OPR quickly. If the tire is cold a heat gun can help with the removal process. If you are gearing up for a time attack, an autocross run or a qualifying lap at the NASA Championships, take the time to remove any OPR before you hit the track. After that, all that is left to do is keep your eyes up and drive fast!
Rob Krider is a four-time NASA Honda Challenge 4 National Champion and the author of the novel, “Cadet Blues.”