Tire sizes are a series of numbers that refer to the tire’s width, aspect ratio and rim size. They are typically found in two places:
- On the tire’s sidewall. (See above image for an example)
- On a sticker on the inside of the driver’s car door.
In the U.S., the accepted measurement for tire tread levels are in 32nds of an inch. Tire tread gauges are used to obtained specific measurements. Most passenger tires start out with a tread level of 10/32.
States that have vehicle safety inspections may require tires to have certain tread depths to pass. Typically, tire tread above 2/32 of an inch is considered to be adequate enough to pass. However, most experts agree that 4/32 is a much safer guideline to follow.
Learn how to use a tire tread gauge.
To find out easily if tires are worn or nearly bald, try the penny test.