Warmer weather is on its way, and with it come school holidays, long weekends and road trips down the Great Ocean Road or further afield. Heat, heavy loads and long stretches at highway speed are tough on tyres, so a little preparation now goes a long way.
Why heat is hard on tyres
Tyres flex constantly as they roll, and that flexing generates heat. On a hot Victorian day, bitumen can be far hotter than the air temperature, and a tyre that is underinflated, worn or old will struggle to shed that heat. Excess heat can weaken the rubber and internal structure, and in the worst case it contributes to a blowout.
The good news is that most heat-related tyre problems are preventable with a few simple checks.
Check your tyre pressure when the tyres are cold
Pressure is the single most important factor. Check it before you set off, when the tyres have been sitting for a few hours, and use the figures on the tyre placard (usually on the driver's door jamb or in the owner's manual) rather than the number on the tyre sidewall.
- Adjust for load: many vehicles specify a higher pressure when fully loaded with passengers and luggage. Check your placard.
- Don't let air out when tyres are hot: pressure naturally rises as tyres warm up during driving. That is normal, and bleeding air out will leave you underinflated once they cool.
- Include the spare: a flat spare is no use on a country road with no phone reception.
Inspect the tread and sidewalls
The legal minimum tread depth in Australia is 1.6 mm across the tread, but for wet-weather grip and a long trip, many drivers prefer to replace tyres well before they reach that point. Look for the tread wear indicators moulded into the grooves, and check for uneven wear, which can point to alignment or pressure issues.
Run your eyes and hands over the sidewalls too. Cracks, bulges, cuts or perishing rubber are warning signs, especially on tyres that are several years old, even if the tread still looks fine. Tyres that spend a lot of time parked in the sun can age faster than you might expect.
Think about your load
Roof racks, boxes, bikes, a boot full of camping gear and a car full of passengers all add up. Every tyre has a load index, and your vehicle has a maximum payload. If you are towing a caravan or trailer, remember that the tow ball weight also affects the load on your rear tyres. Pack heavier items low and close to the centre of the vehicle, and avoid overloading the roof.
Plan for long drives
Sustained highway speeds mean more heat and more wear than short suburban trips. A few habits help:
- Take regular breaks. They are good for you and give your tyres a chance to cool.
- Re-check pressures at a stop partway through a very long trip, remembering that readings will be higher on warm tyres.
- Watch for new vibrations, pulling to one side or a change in how the car feels. Don't ignore them.
Don't forget the basics around the tyres
Wheel nuts should be tight and wheels free of damage. If you have hit a kerb or pothole recently, it is worth having the wheel and alignment checked before a big trip. Misalignment can quietly wear out a tyre edge in a few thousand kilometres, and balancing issues show up as vibration at highway speed.
A quick pre-trip checklist
- Pressures set to the placard, including the spare
- Tread depth and wear pattern checked
- Sidewalls free of cracks, cuts and bulges
- Tyre age considered (the date code on the sidewall shows the week and year of manufacture)
- Load within limits and packed sensibly
- Jack, wheel brace and locking wheel nut key in the car
If you'd like a second opinion before you head off, the team at Global Tyres Geelong in North Geelong can check your tyres, pressures and wheel alignment, and fit new tyres if they are needed, so you can enjoy the drive with one less thing to worry about.