Understanding car tyres guide for dummies

tyre-changing for dummiesAccording to the New Zealand government, we have the third-highest number of cars owned per person in the world. The Motor Trade Association Show told the New Zealand Herald that in 2014 we had around 2.5 million cars on the road, which is more than 1 car per household. That means a whopping 12.5 million tyres spinning around our islands.

But what do you actually know about your car tyres? We asked John Cadogan of www.AutoExpert.com.au for his top 4 tips for understanding your car tyres.

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Front left alert

The front left tyre on your car usually wears out first, for two reasons. Your front tyres have to work harder than the rear ones on most cars because the front end of most cars is heavier – it’s where the engine is, after all. Most cars are also front-wheel drive, so the front tyres are steering and pulling the car forwards with lots of friction while the rears are just lazily following behind. The front left is under special pressure because we drive on the left-hand side of the road and the front left tyre works harder on all those left turns with a tight radius. The right-hand tyre tends to get an easier run because we generally don’t have such tight right turns.

Keep them pumped for a long life

The number one cause of tyres wearing down prematurely is under-inflation. With just a small drop below ideal pressure, the wear and tear rate accelerates dramatically. Check your tyre pressure often – every two weeks at minimum. Don’t forget to check the pressure on your spare. You’ll find the correct pressure for your tyres written on a small sign inside the front door frame. Thankfully, the air at the service station is one of the few things in life that is still free.


If it never rained, tyres would not need tread. Tread doesn’t matter at all in the dry – it’s actually a linear pumping system designed to get water out from under the tyre so it can stay on the road. When new, tyres offer about 8mm of tread, and they’re considered worn out when they get down to 1.5mm at any point on the tread face. By this point they are unable to effectively pump water away. Our car expert John Cadogan says, “Realistically, for safety’s sake, at 2mm it’s time to start shopping for new tyres. Even if it’s not raining…”

Take care of brand new tyres

Brand new tyres have ‘vent pips’ on the surface – these are those little things that look like rubber hair bristles or bumps. The vent pips are vital during manufacturing because they eliminate air bubbles from the tread. But if you buy new tyres and drive hard into a corner, the vent pips can roll flat and actually reduce your tyre’s grip on the road.

New tyres are also coated in ‘mould release’ compound so they don’t stick to the moulds in which they are manufactured. This makes them slightly slippery to the touch when they’re brand new. That’s another thing decreasing your grip on the road.

Between the vent pips and the mould release compound, it’s a good idea to drive conservatively on brand new tyres for the first 100km or so. Pretty soon, normal abrasion with the bitumen and dirt will wear down the pips and wear off the compound.

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