DIAGNOSING YOUR TYRE FAULTS

(By Grant Spolander)

Last month, we spoke about tyre failures, and specifically blowouts. This was the gist of it: more than 99% of all tyre failures are due to driver abuse, and almost all of those cases are related to under-inflation. Which means that 99% of all tyre failures are 99% avoidable.

This month, we’re going to explore a similar topic… tonsils, and how they’re not that different to tyres.

When it comes to uneven tread wear and damage, folks tend to wag their fingers at the manufacturer and proclaim the product to be defective, or poorly designed… but that’s like blaming your tonsils for being infected. What’s more likely is that they’re sore and inflamed because they’re trying to tell you something.

The same goes for your tyres: uneven tread wear is a screaming indication that there’s an underlying problem with your vehicle, your driving habits, or your tyre-maintenance schedule. The problem is very seldom related to the tyres themselves. So, with that in mind, here’s a list of common tyre symptoms and their possible causes:

UNDER-INFLATION

Under-inflation is the number one cause of all tyre issues. If illnesses were tyre problems, then the common cold would be under-inflation, along with the possible risk of a secondary infection and potential fatality (a blowout!).

Symptoms of under-inflation include:

• Outer tread wear

• Chipping

• Sidewall pinching

• Visible cord material

• An open splice

CHIPPING AND CHUNKING

The name says it all. A term used to describe chips, chunks and broken-off pieces of tread. Admittedly, some tyres are more prone to chipping than others. This could be due to a softer compound, or to the fact that the tyre is designed for on-road use, not off-road use. However, without knowing the exact make-up of a tyre, these points are subjective. Most premium-grade tyres use high-quality materials such as Silica, which significantly strengthens the compound and reduces the chance of chipping. However, if a set of tyres does show signs of chipping and chunking, the possible causes could be any, or all, of the following:

• Overloading the tyre

• High torque applications and heavy acceleration

• Off-road use of a highway tread pattern

• Dynamometer damage.

STONE DRILLING

Surprisingly, this a problem that very few people are aware of, and one of the reasons that it’s important to buy a tyre designed with stone-ejecting qualities. Stone drilling refers to a trapped stone that’s lodged between the tread lugs. As the tyre picks up speed (rotations), the stone becomes hotter (due to friction) and starts to burrow (drill) its way through the tread belt. The solution is to keep a Leatherman, or a pair of pliers, in the glove compartment of your vehicle and to remove trapped stones the moment you see (or hear) them.

IMPACT DAMAGE

A tricky one. Impact damage doesn’t necessarily show itself at the time of impact. For example, you could hit a curb (or smack a pothole) and cause internal damage to the tyre. Not seeing any visible signs of damage, you would assume that everything was okay and continue to use the tyre. A few months later, when the tyre has started to develop a sidewall bulge, you would naturally assume (having long forgotten about the past impact) that the tyre is to blame. The fact that a tyre can take so long to reveal impact damage is a testament to the incredible quality of tyres today.

Impact damage can take many forms, but (aside from an obvious slash or cut) a sidewall bulge often looks like a blister that’s about to pop.

FLAT SPOTS

Flat spots usually come from locking the brakes. (Specifically in a vehicle without ABS). However, they can also be the result of:

• Improper tyre balancing,

• Improper bead seating / mounting,

• Loose / Worn suspension components,  and/or

• A progression from previous road-hazard damage.

HEEL AND TOE WEAR

This is a common condition in which the tread pattern is worn high to low, from the front to the back of the tread edge. The condition will often show itself in a ride disturbance (vibration), and/or noise. Common causes are:

• Inadequate tyre maintenance and rotation practices

• Misalignment

• Improper inflation, and

• Misapplication of the tyre.

Of course, there are dozens of other possible tyre problems and causes, but they can’t all be covered here. The fact is that tyres very rarely give problems for no reason, especially when they’re backed by a mileage warranty. For example: if you have four overly-worn tyres that aren’t going to make it to their specified mileage warranty, it’s fairly obvious that something else is to blame. In other words, don’t be too quick to blame the tyre; most of the time it’s hinting at a more obvious problem somewhere else… usually in the driver’s seat.