The replacement of old tires is a common maintenance item, one that also happens to be vital to your safety on the road. Knowing when they’re ready to be switched out isn’t difficult, but it does require a bit of knowledge about tire tread wear and one simple trick.
Since tires are your only direct connection to the road, it’s important that they have a good amount of rubber on them to help the car handle corners, slick surfaces and any other imperfect road conditions. It would be easy to tell you to change your tires at a certain mileage to maintain proper tire tread, but the fact is that the rate at which the tread wears depends on a number of factors, including driving style, vehicle weight and type of tire.
So how do you tell whether your tires are ready for a swap? The penny test is the easiest way to determine that. Simply stick an upside down penny, with Lincoln’s face toward you, into the tread on both the inside and outside of the tire. If you can see the top of Lincoln's head anywhere, the rubber has worn down far enough to warrant a new set.
To be safe, we’d recommend performing this test monthly – even with new tires – because the penny can also tell you if your tires are wearing unevenly. Uneven wear can occur because of over- or under-inflated tires, unbalanced tires or simply from a car’s natural weight dispersion and suspension geometry. If there is a noticeable difference in the tread wear between the front and back tires or on an individual tire, it’s best to take the vehicle to the mechanic and have it checked out.