Nothing is more frustrating than a tire blow-out, or a tire problem requiring an unplanned, early replacement of a new tire. When this happens, we often think the tire wasn’t strong enough or there is some sort of defect in the tire. Manufacturing defect, poor quality or faulty materials are rarely the causes of tire failure. 99% of the time, the causes of tire failure leading to a blow-out or pre-mature tire replacement was completely avoidable with a little more care and attention during routine maintenance or while driving.
One of the main causes of tire failure is under-inflation. Tires that are under-inflated flex more in the sidewall. Excessive flexing causes them to heat up far beyond normal operating temperatures. This problem is compounded when driving at highway speeds during hot weather for long periods of time. When the tire gets excessively hot, the rubber begins to degrade, which if driven on long enough, leads to a rupture in the sidewall of the tire, or tread separation. The result is an immediate and rapid loss of air pressure, often accompanied by a loud bang as the tire explodes.
In addition to the sidewall splitting, the inner liner will usually have evidence that the tire was run at low air pressure before it exploded. When the tire has been removed from the wheel, look for small chunks of burnt looking rubber and dust that has come off the inner liner. If your tire looks like this, it is likely that tire manufacturers, and most extended tire warranty programs, will deny any claim for credit or free replacement.
Misalignment or worn suspension parts are another primary reason a tire does not wear evenly. The tire will be completely worn on one side, or in one area of the tire, but perfectly good, with plenty of tread on the other parts of the tire. The owner has no choice but to replace the tire. Even if only 10% of the tread is worn through, that area will be the weakest and the most susceptible to flats. This condition also contributes to poor traction and ride quality.
There are two tread wear patterns that indicate the type of mechanical problem. The most common is tire wear associated with wheel misalignment. In this situation, one or more of the wheel and tires are going down the road at an angle to the direction of travel, or with too much camber built into the wheel set up. In either case, rubber ends up wearing faster on one side of the tire compared to the other as shown in the photograph on the right. This tire has worn to the cords on one side, but still has plenty of rubber on the opposite shoulder. If the vehicle was aligned correctly, this tire would have worn evenly across the tread, and stayed on the vehicle for another 30,000 or 40,000 miles.
The second wear pattern that indicates a mechanical problem with the suspension of the vehicle is shown below on the left. Broken suspension parts, or worn out and loose bearings or bushings create a wobble in the wheel and tire. Over time the
wobble in the wheel and tire manifests itself in the tire tread rubber, either as cupping on the shoulder tread blocks or as diagonal stripes of wear across the surface of the tread. These wear patterns indicate a serious suspension issue that needs to be addressed for safety reasons and for the sake of the tire tread-life.
While some tires may be slightly more resistant to irregular wear, overtime even the most expensive, premium tires will be replaced early compared to tires on a well maintained and correctly aligned vehicle. Any tire professional or service technician can identify wear patterns on a tire tread associated with mechanical issues. Similar to when tires are under-inflated, tires that exhibit these wear patterns will not be eligible for a free replacement or any sort of pro-rated credit towards a new tire.
If you are driving down the road at 50 or 60 mph and hit a pot-hole, or run over an obstacle in the road, the tire takes the full brunt of the impact. If the impact is hard enough, the sidewall of the tire will compress and be squeezed between the object and the wheel flange. This “pinch-shock” can cause a chunk to come off the tire or a large crack to form on the sidewall where the cords have broken (see photo on left). This is a particularly common occurrence on low profile tires.
Sidewall bulge from broken cords inside tire. While avoidable, road hazards are a fact of life for even the most diligent of drivers. The photo on the left is a tire that has broken internal cords on the sidewall, likely as the result of an impact. The impact broke the cords, but not hard enough to split or crack the rubber. If you see a bulge like this on any of your tires, it should be removed and replaced as soon as possible. If not replaced, the tire could eventually fail.
The best way to get the most mileage out of your tires and to avoid a blow-out is to ensure your vehicle is in good operating condition, check your tire air pressure regularly, and drive carefully to avoid road hazards.