The grooves (or tread) on your car tire’s surface are there not for aesthetic reasons but for safety and performance reasons. Over time, the tread wears out, resulting in less rubber-to-road contact in wet driving conditions (e.g., a wet road on a rainy day). Studies have shown that tires with worn-out tread (called “bald” tires) increase the distance needed by the vehicle to completely stop. Because of the hazards posed by worn-out tires, almost all of the states in the U.S. and Canada have regulated the minimum tire tread depth. Car owners of tires with tread going below the legal minimum are often penalized. This article describes the procedure for checking your car’s tire wear, if not for the sake of safety or performance, then at least to avoid a citation ticket for using bald tires.
First, make sure that your vehicle is at a full stop and that the engine is off. If the vehicle has run for more than two kilometers, wait for the tires to cool down for about thirty minutes. Using the steering wheel, turn the tires either left or right so that they angle out (about 45 degrees should be enough) and give you a good view of the tire for inspection.
Inspect the tread visually. In almost all states, the legal minimum tread depth is 1/16 of an inch. Since 1968, tire manufacturers have been mandated by U.S. law to include a tire tread wear indicator on all tires. The tread wear indicators are small raised blocks of rubber molded in between the treads. The blocks are about half the tread’s actual depth. When the tread reaches the level of the tread wear indicator, you need to change your tires right away.
Another method is to use a penny. Insert a penny, with Lincoln’s head going in first, in the tread. If you cannot see Lincoln’s hairline, then your tire’s tread is still within legal limits, meaning, your tire’s tread depth has not yet reached 1/16 of an inch. Otherwise, it’s time to shop for a new tire. Recent studies have shown that the 1/16-inch legal minimum is barely enough to ensure safety. The studies recommend raising the minimum to 2/16 of an inch. How can you check whether your tire’s tread meets this new suggested standard? Get rid of the penny. Use a quarter instead. As in the penny method, insert the quarter into the tread with George Washington’s head going in first. If the tread covers Washington’s head, the tread is still more than 2/16 of an inch high. Otherwise, replace the tire immediately.
Tread depth is not the only indication of tire wear. Sometimes, a tire with adequate tread depth needs to be replaced because of other tire problems. Check for rips, tears, cuts, or cracks. Check the tire wall for bulging that could weaken the tire wall. Also inspect the tire for embedded objects such as pieces of broken glass or nails. Never try to pull out an embedded piece of glass or nail unless you have a spare tire. It is possible that the nail has punctured only the surface of the tire and not the interior. If you decide to pull out the embedded object, rub some soapy water on the hole. Bubbles will form if there is escaping air from the hole, in which case you will definitely need to replace the tire immediately.
If you regularly check your car tire treads for wear, you will not just avoid tickets but also increase your safety while driving and make your car perform better.