Why do tyres burst in the summer?
Thursday 20th July 2023
Did you know that tyres are more likely to burst in the summer months? This is because hotter temperatures cause an increase in pressure and strain on rubber, increasing the risk of blowouts in tyres that are already worn, under or over-inflated or overloaded. Our guide will explain why you might be more likely to experience a blowout in hotter weather conditions, and what you can do to ensure it doesn't happen to you.
What causes a tyre to burst?
A burst tyre, or blowout, happens when a tyre loses air suddenly because its structure has failed. Unlike a slow puncture, a burst tyre will give you no warning; the tyre simply gives way.
Tyre blowout causes
Several factors can make this scenario more likely.
Tyre pressure – This is one of the most common causes of blowouts. Under-inflated tyres flex more as they roll, and all that flexing generates heat and friction inside the tyre wall, which is a risk. Over-inflated tyres are more rigid and expand further as they heat up, which also raises the risk of a burst.
Worn or damaged tyres – Low tyre tread depth, cracks, cuts and sidewall bulges all weaken the overall structure of the tyre. The age of the tyre matters too, as the rubber becomes brittle over time, even if the tyre tread still looks fine.
Overloading – Extra passengers, luggage or roof boxes associated with summer holidays all add weight that the tyres have to carry. Every vehicle has a maximum load limit, and going over this can put additional strain on your suspension and tyres.
High speed for long durations – Driving fast for long periods, particularly on motorways, builds up heat faster than a tyre can dissipate it.
Impact damage – Hitting a pothole, kerb or other obstacle at speed can damage a tyre's internal structure, even if there's no visible mark straight away.
Why are tyres more likely to burst in the summer?
Heat is the common cause of most summer blowouts. As the air temperature and road surface get hotter, the air inside the tyres expands and internal pressure rises. This, combined with a tyre that's already worn, damaged, has the wrong tyre pressure or is carrying more weight than usual, is often enough to push a tyre past its limit.
Summer driving habits can also add to the risk. Holiday driving can mean longer trips on the motorway, extra luggage and people, all at the same time of year that tyres are already under pressure from the weather.
How to protect your tyres in the summer
Most summer tyre blowouts are avoidable with a few regular checks before long journeys.
- Check tyre pressure: Always check your tyre pressure when your tyres are cool, ideally before you've driven that day. Use the pressure listed in your handbook or on the label inside the driver's door as a guide.
- Check tyre tread depth: The legal limit is 1.6 mm, although we recommend changing your tyres at 3 mm, especially as low tread reduces grip and increases the risk of a blowout in the heat.
- Check your tyres' condition: Look for issues such as cracks, cuts or bulges in the tread and sidewall, and replace if needed before any long journey.
- Stick to your vehicle's load limit: Check the maximum weight in your vehicle's handbook, and avoid packing more than your tyres are rated to carry.
- Take breaks when driving at high speeds on the motorway: Break up your journey when driving at high speeds, not just to give yourself a rest but also to allow your tyres to cool slightly before setting off again.
- Ensure your wheels are aligned: Misaligned wheels cause uneven tyre wear, which can weaken a tyre faster.
What to do if your tyre bursts
Follow our simple 4 step guide on what to do if your tyre bursts:
- Keep calm – Keep both hands on the wheel and resist the urge to make sudden movements.
- Ease off the accelerator – Don't brake hard or accelerate; let your speed drop naturally.
- Pull over somewhere safe – You will not be able to drive on a burst tyre for very long, so you'll need to steer your vehicle to an area of safety as quickly as possible. If you pull over on the roadside, remember to put your hazard lights on and place reflective safety triangles in front and behind your car, if you have them, as this will alert passing motorists that you have broken down.
- Call for recovery or replace your tyre – if you are in a safe location and carry a spare tyre, you can change the tyre yourself, but if your vehicle doesn’t have a spare tyre or you do not feel safe or confident enough to change the tyre yourself you can call for roadside assistance.
Protect your tyres before you set off this summer
A quick pressure and tread check takes minutes and can make all the difference between a smooth journey and a roadside breakdown. Search your registration or tyre size with Formula One Autocentres to book your new tyres and get them fitted for free today.
