How to Measure Tire Tread With a Penny Or a Quarter, by The Ice Cold Garage on YouTube. 2 min 3 s.
- Video length
- 2 min 3 s
- Time to do it
- 10 minutes
- Difficulty
- Easy
- Steps
- 8
What you need
Steps
Park on flat, level ground, switch off the engine and set the parking brake so the car cannot roll while you work.
Wipe dirt and grit out of a wide groove that runs around the tire, not the small slots near the edge.
Push a penny into the groove upside down, with Lincoln's head pointing down toward the tread.
Look straight at the coin. If you can see the whole top of Lincoln's head, the tread is 2/32 inch or less, which is worn out and unsafe.
Repeat the penny test in at least three spots around the tire and in two or three separate grooves across the tread.
Push a quarter into the same grooves with Washington's head pointing down.
If the top of Washington's head shows above the tread, you have under 4/32 inch. The tire is still legal but you should start shopping for new ones.
Run both tests on all four tires and write down the results, noting any tire that reads lower than the rest.
Tips and common mistakes
Test at three points around the tire, because wear is often uneven from bad alignment or low pressure.
Look for the raised wear bars built into the grooves; if the tread is level with them, the tire is finished.
Do the check on clean, dry tires in good light, since dirt or shadow makes the coin hard to read.
A coin is a rough guide, so use a tread depth gauge if you want an exact number in 32nds of an inch.
Questions
What tread depth is legal?
Most US states require at least 2/32 inch of tread. That is the bare legal minimum, so many tire shops advise replacing at 4/32 inch for safe grip in rain.
Can I use the coin test on any tire?
Yes, it works on ordinary passenger car and light truck tires. Just make sure the coin sits in a main groove, not on the shoulder edge where wear reads differently.
Why check with both a penny and a quarter?
The penny shows the 2/32 inch replacement point, and the quarter shows the 4/32 inch point where wet grip starts to drop. Using both tells you whether to replace now or start planning.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
