Have you ever heard someone say you can check your tires with a penny? Well, it may not be 6 sigma accuracy (99.99966% accurate), but it’s a close enough approximation for everyday driving. Let’s see how it works.
The depth gauge is an important tool for us in the automotive profession. The tool is useful to tell us the amount of tread remaining on a tire. When a tire is down to the wear indicators it is at 2/32nd inch tread and should be removed from the vehicle.
“That’s great”, you say. “I’ll Just look out to see when the tread intersects the wear indicators then I’ll know when my tire’s life is over.” Not really, and that’s where you need the gauge. There are several wear indicators spread over a tire’s surface, but they’re not everywhere. If a tire is worn unevenly or choppy the area where there’s an indicator may have a lot of tread and the tire could be down to 2/32nd inches elsewhere.
This is where President Lincoln come in. I’m blabbing on about gauges you don’t own, but you do. In fact, there are probably a few gauges under the driver’s seat.
The depth gauge to the right is measuring the gap to Mr. Lincoln’s head, about 2/32nd, a little closer to 3, but that’s splitting hairs. The image below shows President Lincoln in action showing us a tire in need of replacement. I used this tire on purpose to demonstrate a point. It doesn’t matter where the tire is below 2/32nd inch tread, just that it is. So, When you perform this test, make sure to do it in a few spots.
This tire shows some classic under-inflation wear. It has lots of tread in the middle and none on the shoulders.
So get out there and check your vehicle out and give your tires the Presidential Treatment.
TIA Certified instructor