Why Your Truck Tyres Lose Pressure Every Winter — and What It's Quietly Costing You

Every winter we see the same thing roll through the workshop: trucks running 10 to 15 PSI down on where they should be, drivers swearing they checked them “not long ago.” Nobody let the air out. The cold did.

It’s basic physics, and it catches out plenty of experienced operators. Air contracts as it cools, so the pressure in your tyres drops with the temperature. As a rule of thumb, a tyre loses around 1 PSI for every 5°C drop. A truck set correctly on a mild autumn afternoon can be meaningfully underinflated by the time you’re rolling out before dawn on a frosty Melbourne or Hobart morning.

Why a few PSI matters more than it sounds

Underinflation isn’t just a soft-looking tyre. It changes how the tyre works on the road, and none of it is in your favour.

• More fuel burnt. A soft tyre has a bigger contact patch and more rolling resistance. Your engine works harder to do the same job, on every kilometre, all winter.
• Uneven, faster wear. Run low and the shoulders of the tread take the load while the centre lifts off. You wear the edges out early and lose tread life you’ve already paid for.
• Heat. This is the dangerous one. An underinflated tyre flexes more in the sidewall, and flexing makes heat. Heat is what turns a tired casing into a blowout at highway speed.

That last point is why we get firm about pressure. A blowout on the Hume or the Midland Highway doesn’t just cost you a tyre — it costs you downtime, a towing bill, possible load damage, and on a bad day, a serious safety incident.

”But I run retreads to keep costs down”

Plenty of owner-operators do, and there’s nothing wrong with a quality retread looked after properly. But a retread casing relies even more on correct pressure to survive. Run it soft and hot through a cold, wet winter and you’re shortening the life of the one thing that lets you retread it again. That’s a false economy.

Check it cold, check it often

The single most useful habit in winter is to check pressures cold — before the truck has run, not after a long haul when the tyres have warmed up and the reading looks fine. A warm tyre will read higher and hide the problem.

A quick winter routine that pays for itself:

• Check all positions weekly with a gauge you trust, first thing, before driving.
• Don’t forget the inners on duals — they’re the ones that get missed and the ones that quietly fail.
• Set to the load you’re actually carrying, to the placard or your tyre maker’s figures — not a number you remember from summer.
• Look at wear across the tread while you’re down there. Edges going first usually means you’ve been running soft for a while.

If you’re managing a fleet, this is the season to make pressure checks a logged, non-negotiable part of your pre-trip. It’s cheap, it’s quick, and it’s exactly the kind of preventable wear that shows up in your fuel bill and your tyre replacement numbers before you’ve connected the dots.

Cold mornings hit both ends of our patch

We see it at both depots. Around Melbourne, the early starts down the freight corridors mean trucks leave cold and load up fast. Over in Hobart and the south, the winters bite harder and stay colder longer, so the pressure drop is bigger and lasts most of the day. Different roads, same lesson: the air you set in March isn’t the air you’ve got in June.

If you’re not sure where your fleet sits, bring it in. We’ll check pressures across every position, inspect for the uneven wear and casing damage that underinflation leaves behind, and set everything to the load you’re actually running.

Ruband Tyres has been keeping commercial vehicles on the road since 1998. For a pressure and tyre health check — or 24/7 emergency roadside assistance — call our Melbourne depot at Bayswater North on (03) 9729 8799, or our Hobart depot at Derwent Park on (03) 6272 7500. You can also request a quote and we’ll get back to you.