Heat Cycling
Any DOT race tire is extremely sensitive to the first heat cycle of its use. The first heat cycle can determine performance and wear characteristics. The compounds in a new race tire are “green” and its chemical make up is not fully stabilized.
During the first heat cycle, the tread compound stretches as it heats. The heat can also cause changes at the molecular level. During a heat cycle, bonds are broken and reformed that help to make the tread compound more stable.
The benefit of this process is a tread compound that lasts longer and provides better traction. However, if the first cycle is not performed correctly, the tread may develop irregular compounding, leading to poor wear and inconsistent traction.
Some racers try to heat cycle their own tires, with mixed results. This involves bringing the tires up to race temperatures and then “resting” them for 24 to 48 hours while off the vehicle. This process can be inconsistent as the tires may not heat evenly on the four corners of the car. Also, temperatures across the tread face are not always uniform due to camber and scrub. Plus, if this is the owner’s only set of tires, it is inconvenient to mount and dismount the tires before using them to race.
Some DOT race tire suppliers offer heat cycling services, and use machines that heat the tire by applying a load (no artificial heat). These systems generate uniform temperature build up throughout the tread, a condition not achievable on the track. Because there is no cornering involved, there is lateral scrubbing and virtually no loss of tread during the heat cycling.
