Most are in mm or /32 of an inch.
You should measure tire tread depth in several locations across the tire to get an accurate assessment of wear. The best places are the grooves in the tire tread, specifically in the center, on the inside, and on the outside edges. Use a tread depth gauge or a penny to check; placing the penny with Lincoln's head down into the groove will help you determine if the tread is deep enough. Generally, a tread depth of 2/32 of an inch or less indicates that the tire needs to be replaced.
In California, the legal minimum tread depth for tires is 1/32 of an inch. However, it is recommended to replace tires when they reach 2/32 of an inch for better safety, particularly in wet conditions. To check tread depth, drivers can use the penny test or a tread depth gauge. Regularly inspecting tire tread is essential for vehicle safety and performance.
The test for checking tire tread depth is commonly referred to as the "penny test." To perform this test, insert a penny into the tire tread with Lincoln's head facing down; if you can see the top of his head, the tread is too worn and the tire needs to be replaced. Other methods include using a tread depth gauge or the more advanced "quarter test," where you use a quarter instead of a penny for deeper tread measurements.
It is the depth of the grooves in the tyre.
If you mean tire tread depth, the minimum is 1.6mm.
That depth present on a new tyre.
Minimum LEGAL tire tread depth is 2/32nds of an inch.
The minimum tyre tread depth in the UK is 1.6mm.
The average tread depth of a new radial tire is typically around 10/32 to 11/32 of an inch. This tread depth provides good traction and performance while allowing for gradual wear over the lifespan of the tire.
Purchase a tread depth gauge from your local auto parts store. It will measure in 1/32" increments. Take measurements at the inside, middle and outside of tire treads.
UK is 1mm
In California, the minimum legal tire tread depth is 1/32 of an inch for passenger vehicles. However, it is recommended to replace tires when tread depth reaches 4/32 of an inch for better wet traction and safety. Regularly checking tire tread can help ensure optimal performance and reduce the risk of hydroplaning.