Auto Parts - How Summer Heat Affects Your Tires - New - Blog

Hot temperatures combined with scorching hot pavement create conditions that can negatively affect your tires, their pressure, rubber compounds, and overall lifespan. Here’s what’s happening to your tires as temperatures climb and what you can do about it.

What’s Inside Your Tires Matters

Tires aren’t made of pure rubber. They’re constructed of different layers that include rubber compounds, oils, fabric, and steel bead wire. The oils in the rubber compound are what help keep the tire flexible and grippy under normal road conditions. Excessive heat can cause rubber degradation.

Heat and Tire Pressure

The air expands when temperatures rise. For every 10°C increase in ambient temperature, the pressure inside your tires will rise by approximately 2 PSI. So, on a very hot summer day, your internal tire pressure can rise significantly. This can become a serious safety risk.

A tire running above its recommended PSI has a smaller point of contact with the road. This can cause any of several problems:

• reduced traction
• uneven tread wear concentrated in the centre of the tire
• harsher handling
• elevated risk of a tire blowout (especially with old or damaged tires)

Underinflated tires due to a slow leak or neglect can also be risky in the summer. Hot weather softens the rubber of your tires, which increases the tire’s contact area with the road and generates more friction. Excessive heat will collect inside the underinflated tires, and you’ll face a higher blowout risk.

Before you head out on the road during extreme heat, double-check your tires are inflated to the recommended PSI. You can find this number on the door jamb sticker or in your owner’s manual.

Never use the number moulded into the tire sidewall. That’s the maximum amount of PSI your tire can hold, not the recommended operating pressure.

What Heat Does to Rubber

The oils and chemical compounds that make up your tires help keep them pliable. But sustained heat, from the air and the road’s surface, can dry them out and make them brittle. This can cause cracking along the sidewall, splitting, or even separation of the tire layers.

Pavement temperatures can also significantly increase this risk. At an air temperature of 30°C, asphalt can reach 60°C under direct sunlight. If ambient air is too high, tires can’t cool down.

Keep an eye out for sidewall cracks, bulges, or any surface that looks dried out or discoloured. This can mean structural damage is already present, and you should replace your tires as soon as possible.

What to Check and When

During a particularly hot stretch of weather, follow these important proactive steps to avoid tire damage and heightened safety risks on the road:

1. Check tire pressure monthly and before long trips. Wait at least three hours after driving or conduct your reading before the first drive of the day. Tires should be cold when you check their pressure, since heat from driving can give a false high reading.
2. Use the right PSI reference. Check your door jamb sticker or your owner’s manual for the recommended pressure for your front and back tires.
3. Inspect the sidewalls. Look for cracks, bulges, or any deformation in shape, tread, or colour. A bulge indicates internal structure damage, and the tire needs to be replaced.
4. Check tread depth. Worn tread on hot pavement reduces grip and can increase the risk of hydroplaning during summer rainstorms. The legal minimum in Canada is 1.6 mm, but many experts recommend replacement well before that point.
5. Check the spare. This can be easy to forget. Make sure your spare is inflated and in good condition before embarking on your next road trip.
6. Don't rely solely on TPMS. The TPMS (tire pressure monitoring system) warning light typically only activates when pressure has dropped to a dangerous level. This is a last resort alert that shouldn’t be used as a maintenance tool.

Summer tire care doesn’t require special skills. A tire gauge and a few minutes to look over your tires can make a big difference in prolonging the life of your tires and ensuring every summer road trip is a safe one.

For the best advice, visit your local NAPA Auto Parts store to speak with an automotive expert or browse our full selection of tire maintenance essentials at www.NAPACanada.com.