What is the tread depth of a tire?

[SkylarRose]

The standard for tire tread depth is that greater than 3.5mm indicates a good condition, 2.5~3.5mm is a normal condition, and less than 2.5mm means it needs to be replaced. The tread must be replaced when it reaches the limit of 1.6mm. Below is some information about tire tread depth: 1. National regulations: According to national standards, the wear limit for radial tires used in passenger cars is 1.6mm, while for trucks and buses, it is 2.0mm. Therefore, when the tread of a passenger car wears down to 1.6mm, it must be replaced, and for trucks and buses, the tire must be replaced when the tread depth reaches 2.0mm. 2. Inspection methods: Check using the built-in tread wear indicators on the tire; when the raised portions between the grooves are flush with the indicators, the tire needs to be replaced. Alternatively, use a tread depth gauge to measure the tread depth.