NSRA Autocross 2025 Tires 101
By Kevin Webb NSRA Autocross Director autocross@nsra-usa.com kevin@hotrodcustomgarage.com
O ne of my goals with the NSRA Autocross pro- gram is to get more people of every age involved. Part of that includes track time, but the other equally important area is preparation. This month we are going to talk about tire types, sizing, and tire pressure for the track versus street use. There are two distinct types of autocross drivers, those that just want to test their skills and learn more about how their vehicle handles, and those who want the maximum speed and experience they can get. Our vehicle rules state: “Tire wear rating cannot be less than 200 UTQG (Uniform Tire Quality Grade). What this means is most tires we see driven on the streets are between 400 and 500 UTQG, and these tires are expected to last 40 to 50,000 miles under normal use. Tires rated at 200 UTQG provide much more grip in cornering but tend to wear out faster when driven on regular roads. It’s not unusual for some autocross participants to have a second set of tires/wheels for regular street driving, then switch to the more aggressive set on track days. Does this mean to participate in autocross you have to buy new tires? Not at all, like we’ve said from the start, encouraging participation at your level of racing is always up to you. We always want to educate more people to try autocross for the first time. Along with tire wear there is another considera- tion, tire sizing. We all know how important the cor- rect size tire is on our vehicles because the “right size” gives us the look and stance we like. But tire size affects handling and a perfect example of this happened in NASCAR. The “Next Gen” cars were
introduced in 2022, with one of the big changes being the tire/wheel size. Basically they went from a 15-inch wheel to an 18-inch wheel. This was done to improve handling and allow for bigger brake rotor sizes inside the new wheel. This works the same way in autocross, as your regular 15-inch tire was proba- bly pretty good on the street, but when you tried driving a little faster on a course, you noticed the tire struggling to make the corner. The shorter tire side- wall on larger diameter wheels gives you better cor- nering ability, and the bigger wheel allows for better brakes, which we will cover next month. A switch from 15-inch wheels to something taller (16-18 inch) will allow for a shorter sidewall and better handling. Remember anything larger than 18 inches can start to compromise ride quality on some vehicles. So how do you find the right tire/wheel size for your car or truck? Luckily there’s a lot of information available to help you decide the right setup for your needs. Most tire retailers have a computer program available to “size up” tire/wheel options to insure a perfect fit. There are several tire calculator programs available online to help you match the right size the first time. Don’t forget your best source of information is at any NSRA event where you’ll likely find a similar model vehicle that has the upgrade done. Talk to the owner about the tire/wheel choice he or she made. The right tire combination will provide you the upgrade you might want for better handling. If you have any questions about our program, be sure to reach out at autocross@nsra-usa.com. See you at the track!
18-inch wheel
16 NOVEMBER 2025 15-inch wheel
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