How Heat Damages Your Tires (and How to Prevent Summer Blowouts)
Summer in the Maritimes brings beautiful weather, but the combination of hot asphalt and highway speeds can create a recipe for tire failure. Heat is a tire’s worst enemy. In this article, we explain how heat impacts your tires and what you can do to prevent a sudden summer blowout.
The Physics of Heat and Tires
As you drive on hot roads, friction naturally generates heat within the rubber. At the same time, ambient air temperature affects your tire’s internal air pressure:
- Pressure Spikes: For every 5°C (10°F) change in temperature, your tire pressure changes by approximately 1 PSI. On a hot summer day, your tires can easily gain 3 to 5 PSI just from sitting in the sun, and even more once you start driving.
- Rubber Degradation: Excessive heat accelerates the breakdown of the rubber compounds and weakens the chemical bonds holding the tire's internal steel belts and fabric plies together.
- Under-inflation Hazard: If your tires are under-inflated, the sidewalls flex more. This extra flexing creates immense internal heat, which is the leading cause of tread separation and blowouts.
Three Steps to Prevent Blowouts
- Check Pressure When Cold: Always measure your tire pressure in the morning before driving or after the car has been parked for at least 3 hours. Do not let air out of "hot" tires after driving—the pressure will settle back down when they cool.
- Inspect for Cracks and Bulges: Walk around your vehicle and inspect the sidewalls. Look for fine cracks (dry rot from sun exposure) or bulges (internal belt damage). If you spot any, have them replaced immediately.
- Keep Within Load Limits: Overloading your car or SUV with summer gear adds extra strain and heat to your tires. Check the tire placard on your driver's door pillar for the maximum load rating.