by Pat Goss
A quarter isn’t what it used to be. A quarter is now a penny. Well, at least when it comes to measuring tread depth on tires. See, for many years we’ve been told to take a penny, and we place Lincoln’s head down in the groove of the tire. And if we can see the top of the head, the tire is too worn to use. But, they’ve found that we actually need more tread on a tire to be completely safe. So, the new measurement is using a quarter. We put Washington’s head down in the groove, and if we can see the top of his head, the tire is too worn to use. Now the reason for this is, as tires wear down, they lose their ability to disperse water. And that means that you have a loss of traction on rainy days. So that little bit of extra tread depth means a greater margin of safety. It helps prevent the hydroplaning that is so common.
Now here we have a brand new tire, and we also have a better way to measure tread depth. Instead of using coins, this is a tread depth gauge; it’s about two bucks at the auto parts store. You simply put that down into the tread, and you push it down until it bottoms out, and then you can read the depth of the tread within 1/32 of an inch. Replace a tire at 4/32 of an inch, instead of the old 2/32 of an inch, if you want really good wet traction throughout the life of the tire. Now another big controversy: how old can a tire be and still be safe? Some people say five years, others say six years. Personally, I look toward five years. Now, like this brand new tire that we have here, it’s never been sold, but it’s already eight months old.
Now how do you tell the age of tires on your vehicle? Well, on the side of the tire, stamped into the rubber, is a DOP label. And it is four numbers long. It tells you the week and the year your tire was manufactured. You don’t want to go beyond five or six years. Now certainly, if you’re only driving the car a couple of miles, or at very low speeds back and forth to the store or something like that, it isn’t nearly as critical as if you’re going to get out on the road and travel at high speeds or long distances. But, you know it’s better to be safe than to be sorry for sure. So, follow the rules, and you’ll have a much safer ride. And if you have a question or comment, drop me a line. Right here, at MotorWeek.