Cracked tyres and why they need replacing - Mick's Tips 437

By: Mick McCrudden

Date: 22.03.2020

Mick reckons that if you're seeing cracks it's time to get new rubber

Tired Tyres

We’ve touched on tyres before when it comes to pressures and patterns, but let’s have a crack at weathering, damage and neglect. One of the things we have in the modern world is this very fashionable thing where people want to maintain the original patina (I hate that word) of a car. That might include the odd bump and scratch, oil stains, missing chrome, whatever.

It has to have original everything, including the tyres which you pumped up and they held air! They might hold air, but they’re buggered. Move on and get another set.

The simple fact is that the rubber in your tyres deteriorates and goes hard and weird over time. This might manifest itself as cracks in the rubber and, if it’s got to that point, your tyre has gone from being past its service life to downright dangerous.

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All sorts of things will upset the health and well-being of your tyres, including age, exposure to sunlight, sitting too long in one place and, of course, being allowed to go flat over time. Those last two can be particularly irritating, as they’ll create flat spots and accelerate sidewall damage.

Just for your own info, vertical cracks in tyres are generally just a symptom of old age, while horizontal cracks are often the result of abuse or neglect – typically from having being driven at too low a pressure.

Now, the industry says you should be giving rubber the flick at seven years, which is probably about right, but let’s be generous and say 10 at the outside. After that, though you may have a heap of tread left, they will be well past their best. In either case, it means the construction is compromised.

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Since we all seem to have old cars tucked away that only get dragged out for the odd Sunday drive, this takes on a whole new importance. You probably won’t notice the deterioration in grip and suspension response (yes, tyres are a critical part of our suspension) as it happens very gradually. However, do you remember what it’s like when fresh rubber goes on? The car suddenly feels more crisp and responsive, yes? That’s not your imagination.

For me, if I see cracks, cuts or any damage in the tread – including punctures that might have been repaired to get me home – I’m looking for a replacement. Whatever they cost, it’s still a whole lot cheaper than having the thing spear off into the scrub when you least expect it.

Just as a final thought, there’s an old truism that 90 per cent of punctures and leaks happen in the last 10 per cent of the life of the tyre. That’s about right. Replacing the set if one gets damaged and the rest look a little past their prime, makes lots of sense.

Note: Mick runs Glenlyon Motors in Brunswick, Vic.
Tel (03) 9380 5082.

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