Summer heat could damage tires

Hanover, Germany August 1, 2023. The heat wave currently sweeping through Southern Europe is not only a serious health hazard for many people but could also damage your car tires. “Underinflated tires and extreme temperatures on long journeys can be dangerous,” warns Andreas Schlenke of Continental’s tire development division in Hanover. “Contact with the hot asphalt and the high air temperatures prevent a tire from cooling down. If the tire is underinflated, tire shoulder and sidewall deformation can occur, resulting in rolling resistance. This causes the rubber to heat up even more. If all these factors combine, or if the tire has been previously damaged by curb contact or the like, a blowout is a distinct possibility.”

Even at an air temperature of 30 degrees, the asphalt can heat up to 60 degrees. The heat wave in Europe is already pushing temperatures up to 40 degrees in some places, and the forecast for southern Europe is already close to 50 degrees. “Asphalt temperatures of over 80 degrees Celsius are entirely possible,” explains Schlenke. “You shouldn’t endanger your safety with unnecessary car trips in temperatures like this,” he advises. Driving on winter tires in these conditions is extremely risky because their rubber compound is softer than summer tires and heats up more. “This can be really dangerous,” he warns. Even in high temperatures, cars running on all-season tires are safe to drive if they’re correctly inflated – their tread and rubber are a mix between summer and winter tires, so they’re not as sensitive to heat as winter tires.

Continental advises all drivers to drink plenty of fluids and stay in the shade or indoors as much as possible during periods of high temperatures – and not to park where the car and its tires are exposed to direct sunlight.

When tires roll on the road, they are constantly flexing. Internal friction on molecular levels as well as in the footprint slowly warm up the rubber. Tires reach their typical operating temperatures after a few miles.  High ambient temperatures increase the tire’s operating temperature and hot asphalt adds higher heat inputs. In addition, warm air flowing around the tire is not as effective at cooling the rubber. This coupled with heavy loads and extended periods of high speeds may further increase the tires operating temperature. Under these severe service conditions, it is important to control the amount of tire flexing through proper inflation pressure in the tires. Continental recommends to check the pressure at least once per month when the tires are cold, and always adjust the inflation pressure to the vehicle manufacturer’s recommended levels. These recommended inflation pressures are listed on the vehicle’s tire placard, which is typically found on the driver’s side door jamb or inside the access door for the vehicle’s fuel tank. In addition, Continental strongly recommends replacing winter tires with summer or all-season tires in areas with hot ambient temperatures. Dedicated winter tires are not intended for use in extremely hot environments.