How to check your tyre tread

Tyres are the only items on your vehicle which grip the road. Those in good condition help to promote safety, comfort and vehicle performance – those that are worn or damaged pose a danger not only to you, but to other road users.

Driving with low tread depth increases the potential for tyre failure and, in wet weather, loss of vehicle control through aquaplaning.

These are among the reasons why it’s important for you to inspect your vehicle’s tyres regularly – at least once a month and before and after long journeys – to ensure that they remain roadworthy.

The legal minimum tread depth in South Africa is 1,6mm across the central three-quarters of the tread width and around its entire circumference. But it’s not only tread depth that matters – the condition of sidewalls is vitally important, too.

 

1.  Checking the tread

Begin checking the tread depth of the tyres.

Don’t rely on guesswork – purchase a tread depth gauge to ensure proper accuracy and follow the manufacturer’s instructions in measuring both the inside and outside of the treads.

Additionally, most tyre manufacturers these days incorporate depth indicators within the tread pattern to help you determine just how worn the tyre’s surface is. If the indicators – little bars of rubber that are spaced at intervals within the tread grooves – are clearly visible and at a level that equals that of the remaining tread, the tyre is deemed to have reached the end of its life and requires replacing.

To find an indicator, look on the sidewall’s shoulder for a small triangle. It points to the spot at which a bar or series of bars is located.

During your inspection, check for objects that might have become lodged in the tread. Stones are common and are usually easy to remove, but if you spot something that appears to have gone through the casing – such as a nail or other sharp object – remove the wheel and replace it with the spare, then take the damaged tyre to a repair outlet for proper assessment.

 

2.  Wear patterns

If your vehicle’s tyres are worn on the outsides, they might be under-inflated.

Tyres lose air naturally, but driving on tyres that aren’t pumped to their recommended pressures uses more fuel and impairs safety.

Conversely, if the centre of the tread appears to be wearing more than the outer edges, you might be driving on over-inflated tyres. For these reasons, we recommend that you check your vehicle’s tyre pressures at least once a fortnight.

Finding uneven wear across a single tyre might be indicative of problems elsewhere. You might have to have your vehicle’s wheel alignment checked or the balance in the tyre corrected. Sometimes bald spots indicate that the vehicle’s shock absorbers – or other suspension parts – are worn.

Tyres don’t wear down at the same rate. Those at the front usually carry the weight of the engine as well as doing the steering, and are often also the vehicle’s drive wheels. These factors mean that they tend to wear quicker than tyres at the back.

With a view to keeping wear patterns even, we recommend regular rotation intervals – every 10 000km – in which front and rear tyres swap positions.

If wheels on one side of the vehicle seem to be wearing faster than those on the other, suspension components and wheel alignment should be checked. If you notice a saw-toothed or feathered appearance around the edges of a tyre, the likely cause is erratic rubbing against the road and again, it could be a sign of worn suspension, steering, imbalance or incorrect alignment.

 

3.  Checking the sidewalls

Damage can include cuts, tears, bulges or scrapes anywhere along the sidewall of the tyre and can be caused by anything from impact damage associated with hitting a pothole or other blunt object, or through abrasion caused by scraping against a curb.

A bulge that appears on the sidewall is usually a sign of severe damage and the tyre should be replaced immediately, since its structure is likely to have been radically compromised. Often, bead problems – manifest in the form of a broken seal against the rim, chafing of the rubber or deformation – are associated with the appearance of a bulge.

If such damage is ignored you run the risk of complete tyre failure, in which the tread could delaminate or the sidewall disintegrate. If you spot sidewall damage have the tyre assessed by a professional – even it looks as if there are many thousands of kilometres left in its tread.