Tyre Myths Australian Drivers Still Believe

Tyre advice spreads faster than it’s checked. Some of it is outdated, some is imported from the UK or US and doesn’t fit Australian law, and some was never true. Below are the most stubborn myths we still hear in Australian tyre bays — and what’s actually correct.

Myth 1: The legal minimum tread is 1.6mm

This one is imported straight from the UK and Europe. Australia’s legal minimum tread depth is 1.5mm across all principal grooves, not 1.6mm. The confusion is understandable — many tyres’ moulded wear indicators sit at 1.6mm, and some overseas warranty documents quote 1.6mm. Either way, 1.5mm is the point of illegality, and it’s a bare minimum: the NRMA and most fitters suggest replacing at around 3mm, because wet braking falls off a cliff below that. See our full breakdown of the 1.5mm rule.

Myth 2: The pressure on the sidewall is the pressure to run

The big number on the sidewall (e.g. “max 350 kPa”) is the maximum the tyre can safely hold — not the recommended pressure. Your correct cold pressure comes from the tyre placard, usually on the driver’s door jamb or inside the fuel flap, matched to your vehicle’s weight and load. Running to the sidewall max over-inflates most cars, giving a harsh ride, centre wear and less grip. Follow the placard, not the sidewall.

Myth 3: Nitrogen fill is a must-have upgrade

Nitrogen isn’t a scam, but the marketing oversells it. Air is already about 78% nitrogen. Pure nitrogen leaks very slightly slower and is less affected by temperature, which matters for aircraft and race cars. For a daily driver, the real-world benefit over free compressed air is marginal, and the catch is you can’t top up with ordinary air without diluting it. If it’s free with a tyre purchase, fine; paying a premium for it rarely pays off. More on nitrogen fill value in Australia.

Myth 4: Bigger tyres are always better

Up-sizing looks good and can sharpen steering, but it’s a trade, not a free win. Taller tyres throw out your speedo, bigger diameters can rub or need re-gearing, lower profiles ride harder and bruise rims on potholes, and wider or heavier combos cost fuel and can exceed your placard load rating. On 4WDs, 33-inch tyres add fuel cost and stress driveline parts. Choose size for purpose, within legal limits.

Myth 5: New tyres go on the front

It feels intuitive to put the fresh rubber on the driven or steering wheels — and it’s wrong for most cars. Fitters and tyre makers fit the newer, deeper tyres on the rear axle. The reason is stability: worn rears let the back of the car step out and oversteer in the wet, which is far harder to catch than front-end understeer. When you buy two tyres, ask for them on the back.

Myth 6: You must always replace all four at once

Not always. On a two-wheel-drive car you can replace in pairs (same axle) if the tread difference is modest. The “all four” rule genuinely applies to AWD and 4WD vehicles, where mismatched rolling diameters can damage the centre diff or coupling — there the all-four replacement is real, not a sales pitch.

Myth 7: A plugged or patched tyre is never safe

A proper internal patch-plug fitted from inside the tyre, within the repairable crown area, is a legitimate permanent repair recognised across the industry. What’s not safe or legal is a repair in the shoulder or sidewall, or an external-only string plug left as a permanent fix. Know the difference before you dismiss — or trust — a repair.

Myth 8: Tread depth is all that matters for age

Plenty of tread doesn’t mean a safe tyre. Australian UV and heat age rubber from the inside out, causing cracking and hardening even on a tyre that’s barely worn. Read the DOT date code: most makers suggest inspecting from five years and replacing by about ten, regardless of tread. A low-kilometre garage-queen can be the most dangerous car in the street.

Myth 9: Wheel balance and wheel alignment are the same thing

They’re completely different jobs. Balancing corrects weight distribution around the wheel so it spins smoothly (cures vibration). Alignment sets the angles the wheels point at (cures pulling and uneven wear). One doesn’t fix the other — see alignment vs balance.

Myth 10: Premium tyres are a rip-off (or: cheap tyres are just as good)

Both extremes are myths. Premium tyres generally brake shorter in the wet and last longer, but the gap narrows against good mid-tier brands, and the “best” tyre depends on your car and use. The honest answer lives between the slogans — compare on cost per kilometre and independent wet-braking tests, not price alone.

At-a-glance: myth vs fact

Frequently asked questions

Is 1.6mm or 1.5mm the Australian legal limit?

1.5mm in all principal grooves is the Australian legal minimum. The 1.6mm figure is from overseas and also happens to be where many wear indicators sit — but the law here is 1.5mm.

Why do shops put the new tyres on the back?

Worn tyres on the rear cause oversteer in the wet, which is harder to control than front-end slip. Deeper tread on the rear keeps the car stable.

Does nitrogen stop my pressures dropping?

It slows the drop slightly and is less temperature-sensitive, but all tyres lose a little pressure over time. You still need to check monthly, nitrogen or not.

Can I just replace one tyre?

On a 2WD, sometimes — if the others have similar tread. On AWD/4WD, mismatched diameters can damage the driveline, so replacing all four (or at minimum a matched axle pair within tolerance) is the safe call.

Figures and rules here are general guidance for 2026; confirm specifics with your vehicle placard, handbook or a licensed fitter. See the NRMA’s tyre-check guide and tyrereview.com.au on nitrogen fill.

Related reading: The 1.5mm tread rule · Placard vs sidewall pressure · Is nitrogen worth it? · Tyre rotation patterns · Alignment vs balance · Reading a tyre label · Tyre recalls in Australia