“Tire deg.” If you follow racing, you’ve heard the term. It’s short for “tire degradation,” but it doesn’t necessarily mean what it seems. It’s not simply about tire wear. It’s a complicated mix of temperature, surface, compound, conditions and driving style. In other words, all the elements that cause rubber to break down and wear out.
Tires on a passenger car will wear out in about 50,000 or 60,000 miles of normal driving. In racing, though, the driving is far from normal, and tires wear out — seeing their ultimate grip when in contact with the track surface decrease as the rubber tread compound gradually shreds away due to the continuous frictional confrontation between tire and track — over the course of a single stint of a race.
And, unlike your daily driver, tire deg on a race car affects performance and traction as soon as a stint begins. If not managed properly, tires can lose grip dramatically and quickly, leaving a racer with a car that doesn’t respond the way it would with fresh tires.
“It sounds obvious, but if you don’t slide the tire, it’s not going to wear as quickly,” said Ricky Taylor, who’ll drive the No. 10 Wayne Taylor Racing Acura ARX-05 with Filipe Albuquerque in the IMSA Fastlane SportsCar Weekend at Road America this weekend. “That’s so much easier said than done when you’re trying to push the limits of the car. To be competitive in such a high-pressure situation, sometimes you have no choice but to push the car over the limit. That’s where the more experienced drivers can use their expertise to exploit the limit of the car without sliding the tire too much.”
Saving tires is an art that most successful racers have in common. Driving fast while minimizing tire wear is a skill born of experience and information. Knowing how each track wears out tires is a critical piece of information in each team’s arsenal.
“A lot of historical experience that we have can give us plenty of information about what the tire is going to do,” Taylor said. “There are definitely some people who are better at it than others.”
As much as all tracks are different in relation to tire wear, so are cars — and so is the difference between tire deg on the front and rear tires. Road America’s 14-turn, 4.048-mile circuit is notorious for tire wear, and for the difference in wear between fronts and rears.
The Carousel — the high-speed right-hander that makes up Turns 9 and 10 — is particularly rough on tires. Especially front tires, Taylor said.
“With the Carousel being so important for front grip, Road America jumps out as a place that’s hard on tires,” Taylor said. “Looking back, you can study what went wrong and you can identify what you can do better.”
That’s exactly what teams do. They record the wear of each tire under testing, practice and race conditions, noting the length of the stint and the track conditions. That gives engineers a solid base on which to make decisions regarding the car’s setup.
“A lot of the tire saving is done before the race weekend starts — how you set up the car to favor a certain end of the car,” Taylor said. “Is it a soft or stiff car? Are you favoring the rear in order to save your rear tires?”
It’s one of the many elements of racing that gets overlooked. To get to the finish line ahead of everyone else, a driver and team have to preserve their tires. It’s not as simple as two words.
“Tire deg is one of those things that affects so much of the car setup,” Taylor said. “We gather that experience over the years.”