Though tires have come a long way, the thought of a blowout caused by a faulty or worn tire is still frightening. Also scary is the thought of skidding over wet roads due to hydroplaning. Luckily, most modern tires have been built to last and, at the very least, they will show appropriate signs of age before they pose a risk. Keeping a close eye on your tires can also give benefits beyond safety alone – gas mileage, comfortable riding and handling are all affected by your tires. Learning to read your tires is an important part of vehicle ownership and here is how to do it.
When most people think of tire safety they think of tread depth. The tread is designed to provide an optimal level of road grip and water-cutting ability that allows for safe driving. The most obvious place to read tire wear is based on tread depth – the rule of thumb is tires with less than one-quarter inch of tread depth should be replaced soon, especially if they see frequent high-speed highway use.
However, there are more points of interest along the tread. Inflating your tires to the proper pressure is necessary to maintain a safe, comfortable and gas-efficient ride. This is due to the “pillow effect” cause by tread meeting the ground. In over-pressurized tires, the amount of tread meeting the ground is too little and can cause poor road grip and handling. In under-pressurized tires, the amount of tread meeting the ground is too great and can cause poor gas mileage and a greater chance of picking up nails or other road trash. And don’t think that that PSI number on the sidewall is the correct pressure either – it is actually the maximum pressure. Read your owners manual for the correct pressure for your model tire and vehicle.
The sidewall of a tire is the area that faces away from and into the vehicle (it has the text on it). This point of interest is about both tread depth and sidewall stability because it involves tire rotation. Rotating your tires is necessary because of the uneven amount of weight distribution in an automobile and the wear caused by steering. First, the engine weight places a large amount of load on the front tires, causing them to wear faster. Rotation ensures an even wear between front and rear tires. Second, tires pitch in angle away from and toward the vehicle when you turn the wheel and this causes “shoulder wear”, wear from the tread to about two inches down the sidewall. Shoulder wear only occurs on steering tires which are most commonly in the front – rotation ensures that shoulder wear is even among all tires. Keep in mind that the sidewall and shoulder are the most vulnerable parts of the tire to blowouts, not the tread.
Uneven tire wear, bubbles and other such odd features can appear on your tires and they deserve your immediate attention. Uneven wear along a single tire can indicate a suspension problem in your vehicle. You may notice flat spots in the tread while the rest of the tread is quite deep. This may be due to an alignment or ball joint issue. Believe me, you do not want to be driving a vehicle when a ball joint pops loose – the tire flings out away from the car and steering control is impossible, even at high speed.
Any strange anomalies in tire wear such as bubbles or visible belts should be immediately serviced for safety reasons. The tire may be defective or prematurely wearing.
Last to discuss is balancing. Small weights are placed on the tire to balance it as it spins down the road. All new tires are balanced before installation, but sometimes tires in use can lose weights or develop balance issues. Balancing ensures a smooth ride and even wear.