Blistering

Blistering occurs when the internal temperature of a tire’s rubber compound becomes significantly higher than the surface temperature. This localized overheating causes the rubber to soften and expand, forming air bubbles—or blisters—beneath the surface. As the car continues to corner at high speeds, these bubbles eventually burst, causing chunks of rubber to tear away from the tire’s carcass. This leaves a pitted, uneven surface that looks like a series of small craters.

Why It Happens

This phenomenon is typically caused by high track temperatures or excessive energy being put through the tires on high-load circuits. If a driver pushes too hard on a fresh set of tires before they have stabilized, or if the car setup causes the tire to flex excessively, the internal heat builds up faster than it can be dissipated through the surface. High-speed corners, such as those found at Silverstone or Spa-Francorchamps, are notorious for inducing blistering because they generate immense lateral forces.

Impact on the Race

A blistered tire is a major disadvantage. The uneven surface reduces the contact patch with the asphalt, leading to a significant loss of grip and slower lap times. Furthermore, the missing chunks of rubber cause intense vibrations through the steering wheel. These vibrations make the car difficult to handle and can eventually damage the suspension components or lead to a structural tire failure if the driver does not pit for a replacement.

Blistering vs. Graining

Viewers often confuse blistering with graining, but they are opposites in terms of cause. While graining is caused by the surface of the tire being too cold and "stripping" away, blistering is an internal heat issue. Graining can sometimes "clear up" as the tire warms and the surface smooths out, but blistering is permanent damage that usually requires a pit stop to resolve.

Recent Examples

The 2020 70th Anniversary Grand Prix at Silverstone is a notable example. High ambient temperatures and the high-speed nature of the track saw several teams struggle with severe blistering on their rear tires. This forced many drivers into defensive strategies, as they had to manage their pace to prevent the tires from literally falling apart before the end of their stints.