The difference between winning and losing a Solo National Championship may be just a few degrees
It seems like just yesterday that the only decision to make was whether or not you wanted a co-driver to warm your autocross tires. But while this is still a tried and true method by many, other competitors have taken a far more active approach to autocross tire temperature management. But do these methods work, and is all of the effort necessary?
“Many autocrossers have probably seen the same grid where one competitor is using blankets and another has the water sprayer out,” says Peter Calhoun, Motorsports Marketing Manager, BFGoodrich Tires. “The use of static tire blankets and water spraying has become that of urban folklore amongst the hardcore Solo community, and it’s something that is not part of our formal testing procedures.”
The fact is, most modern Extreme Performance Summer tires, like those found on autocross courses or in use at track events, offer a reasonably wide operating temperature range. “The number of variables is infinite when it comes to weather, track surface and conditions, vehicle design, setup, and driver preference,” says Calhoun. “In the case of the BFGoodrich g-Force Rival S, the normal operating range is 100-175 degrees F. If the Rival S were to peak at 190 degrees F or higher, its grip and ultimate performance will decline and cooling will be appropriate.”
Optimizing your car’s balance from one autocross run to the next can be a challenge; for some, the easiest thing to do is to cool the tires in an effort to keep things consistent, while others may be more flexible and tune the car as needed. Either way, there are things to consider.
“An important consideration for drivers to take into account is the downtime between runs; will that time in grid be enough to allow the tire to naturally cool down, while maintaining the operating tire pressures,” says Calhoun. “This is a big difference between autocross and other forms of racing. Autocrossers most often talk about cold tire pressures due to short run times, while circuit racers are always shooting for a target hot pressure for maximum performance where track time is measured in minutes or hours, not seconds.”
If you find yourself needing to cool your tires, try not overdoing it as that can potentially take the tire below its optimum temperature range before your next run. “Watering down the tire is only necessary if the temperature was too high and borderline of being greasy,” says Paul Jho, Motorsports Senior Manager at Nexen Tire. “I normally suggest cooling down a tire slowly, therefore it wont take too long to reach the optimal temperature between runs. Watering down will lower the temperature and possibly can help longevity, but it’s possible to loose optimal grip.”
For competition-specific tires, much of the same is true, and while some may be marketed as an autocross-specific application, most are much more robust than you might expect. It’s just as common to see tires like the Hoosier A7 on the grid at events like the SCCA National Championship Runoffs as it is to see them at the Tire Rack Solo National Championships.
“The [Hoosier] ‘A’ compound is pretty amazing – we’ve had it around forever as compounds go,” says Tim Gilvin, Hoosier Tire Circuit Racing Product Manager. “The Solo crowd will shoot for 110-140 degrees F temperature range. But lets say they are autocrossing a Corvette and then the person takes the same Corvette to Road America on the same A7 – at 240 degrees F the tire will be sticking like glue coming around the Carousel.”
Indeed, finding and maintaining the ideal tire temperature for your autocross car’s setup is more complicated than blindly using tire blankets or spraying water over the tire’s contact patch. But if the process is taken seriously, you may discover the pursuit for the ideal tire temperature is the missing link to your Solo success.