Ever noticed your tyres looking a little flat on a frosty Geelong morning? You're not imagining it. Air contracts as it cools, and for every 10 degrees the temperature drops, your tyres lose roughly 1 to 2 PSI. That means the pressure you set back in summer could be well below the recommended level by mid-winter, even if your tyres are in perfect condition.
Why low pressure matters more than you think
Underinflated tyres are one of the most common issues we see, and it's easy to understand why they slip under the radar. A tyre can be 20 per cent below its recommended pressure and still look normal to the eye. But the effects add up quickly:
- Longer stopping distances. Soft tyres flex more and put less consistent rubber on the road, which matters most on cold, wet winter roads when grip is already reduced.
- Higher fuel bills. Underinflated tyres create more rolling resistance, so your engine works harder. Keeping tyres at the correct pressure is one of the simplest ways to trim your fuel consumption.
- Faster, uneven wear. Low pressure causes the outer edges of the tread to wear ahead of the centre, shortening tyre life and potentially costing you hundreds of dollars in early replacements.
- Heat build-up and damage. A flexing, underinflated tyre generates extra heat, which over time can damage the internal structure of the tyre.
Finding the right pressure for your car
The correct pressure isn't printed on the tyre itself — the number on the sidewall is the maximum, not the recommendation. Instead, check the tyre placard, usually found on the driver's door jamb, inside the fuel flap, or in your owner's manual. Most passenger cars sit somewhere between 30 and 38 PSI, and many list a slightly higher figure for carrying heavy loads or towing.
How to check pressure properly in winter
A few simple habits make all the difference:
- Check when the tyres are cold. Pressure rises as tyres warm up, so check first thing in the morning or after the car has been parked for a few hours. If you drive to a servo, keep it under a few kilometres.
- Check monthly, not yearly. Tyres naturally lose a small amount of air every month even without a leak, and winter temperature swings accelerate the drop.
- Don't forget the spare. A flat spare is no help on the side of the Princes Highway. Give it a quick check while you're at it.
- Use a reliable gauge. Servo gauges cop a lot of abuse and can read inaccurately. A small digital gauge from an auto shop is a cheap way to be sure.
What about tyre pressure monitoring systems?
Many newer cars have a tyre pressure monitoring system (TPMS) that warns you when pressure drops. It's a great safety net, but most systems only alert you once a tyre is significantly underinflated — often 25 per cent or more below the recommended level. By that point you've already been losing fuel economy and grip for a while, so a manual monthly check is still worth doing.
A five-minute job that pays for itself
Checking your tyre pressure takes about five minutes and costs nothing, yet it improves your safety, extends your tyre life and saves fuel all winter long. Put a reminder in your phone for the first weekend of each month, and your tyres — and wallet — will thank you.
If you'd rather have a professional take a look, the team at Global Tyres Geelong in North Geelong are happy to check your pressures, inspect your tread and make sure your tyres are ready for the rest of winter — just drop by next time you're passing along Thompson Road.