The “penny test” – done by inserting a penny upside down into your tire’s grooves to see how much of Abe Lincoln’s head is exposed – was once the gold standard for drivers. But that’s no longer the case. Especially for cars and trucks that deal with the rain, snow and mud Madison area drivers face. A Consumer Reports test showed that tires with 2/32 of an inch of tread (the amount left if only a small part of Abe’s head was covered) took two times as long to stop as those tires with about 5/32 inch of tread. The results were worse in rain, mud and snow. Overall grip was better with the less worn tires.
The new rule of thumb test is to use a quarter. If the top of George Washington’s head is covered by the tread, you have about 4/32 of an inch of tread left. But the best test of all is to let a professional tire expert evaluate your tires. – Will C. Sparks