Why does a heatwave put your tyres at risk?
A heatwave attacks tyres on three fronts at once. It softens the rubber, which speeds up wear; it raises the air pressure inside the tyre; and it ages the rubber compound faster. The road itself is the hidden factor — according to Continental, when the air temperature is around 30°C the bitumen can reach about 60°C, and in a genuine heatwave the surface can climb past 80°C.
None of that is usually enough to wreck a tyre on its own. The danger is cumulative: an underinflated, damaged or old tyre carrying a heavy load at highway speed generates heat faster than it can shed it, and that is when a blowout becomes likely. If you want the deeper science, our guide to how 40-degree bitumen shortens tyre life covers it in detail.
Should you let air out of hot tyres in summer?
No. This is the most common and most dangerous heatwave mistake. Pressure naturally rises as a tyre warms up with driving — typically by a couple of psi — and that increase is completely normal. The figure on your placard is a cold pressure that already allows for it, as we explain in cold versus hot tyre pressure.
If you bleed air out of a hot tyre to “bring it back down”, it will be dangerously underinflated once it cools. Underinflation is exactly what causes the sidewall to flex, overheat and fail. Always set pressures cold and leave hot tyres alone.
How should you set tyre pressures in hot weather?
Check and set pressures when the tyres are cold — first thing in the morning, or after the car has been parked for at least three hours. Use the placard figure (usually on the driver’s door jamb or inside the fuel flap), and switch to the higher “loaded” figure if you are carrying passengers and luggage. Continental recommends checking at least once a month with the tyres cold; in a heatwave or before a long drive, check the day before you leave. See how much summer heat raises your pressures and, if you follow the number on the tyre instead, placard pressure versus the sidewall maximum.
| Heatwave check | Why it matters |
|---|---|
| Pressures set cold to placard | Prevents the flex and overheating that cause blowouts |
| No bleeding hot tyres | Avoids leaving tyres underinflated once cool |
| Inspect sidewalls for cracks/bulges | A bulge is a failing tyre — it is not repairable |
| Check the age (DOT code) | Rubber over ~5 years old tolerates heat poorly |
| Park in shade or a garage | Cuts UV and heat soak that age the rubber |
What heat damage should you look for?
Australian sun is brutal on rubber. Look for the fine surface crazing of UV damage and dry rot, deeper sidewall cracking, and any bulge or bubble — a bulge means the internal structure has already failed and the tyre must be replaced, not repaired. Older tyres are the most vulnerable, which is why it is worth checking whether to replace tyres over five years old before summer touring. Road safety bodies consistently link summer blowouts to tyres that were already worn, old or underinflated.
Does parking in the shade actually help?
Yes. Direct sun both heats the tyre and speeds up UV ageing of the sidewall. A garage, carport or even the shaded side of the street reduces heat soak and slows that ageing. It matters most for a vehicle that sits parked all day in full sun during a heatwave, and for tyres that are already a few years old.
Does a heatwave change how far and fast you should drive?
It can. Heat builds in a tyre the longer and faster you run it, so on a 40-degree day a long highway stint loads the tyres thermally far more than the same drive in mild weather. On a big touring day, build in rest stops that let the tyres (and you) cool, avoid overloading the vehicle, and don’t drop pressures below the placard to “soften the ride” — low pressure is the single biggest heat generator. Caravan and trailer tyres deserve the same attention: they are often older, carry heavy loads and sit out in the sun, which is a classic blowout recipe. Check the spare too, since a heatwave is the worst time to discover it is flat or perished. If a tyre looks or feels unusually hot at a stop, let it cool rather than bleeding air out of it.
Frequently asked questions
Can heat cause a tyre to blow out on its own?
Rarely. A correctly inflated, undamaged, reasonably new tyre copes with Australian summer heat. Blowouts happen when heat combines with underinflation, a heavy load, high speed or an already-damaged or aged tyre.
What tyre pressure should I run in summer?
The cold placard pressure — do not add or subtract psi to “allow for” the heat. The placard figure is already a cold pressure that accounts for the normal rise as tyres warm up.
Is it risky to drive on hot roads with worn tyres?
Yes. Worn tyres run hotter, grip less and have less margin before failure. Australia’s legal minimum tread is 1.5mm, but for hot-weather safety replace well before that.
How hot do Australian roads actually get?
As a guide, bitumen reaches around 60°C when the air is 30°C, and can exceed 80°C during a heatwave. That surface heat is a big part of why tyres run so hot in summer.
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