The tread wear indicators or wear bars are equivalent to the legal tread limit, which is 1/32nd or 2/32nds of an inch, depending on the state. If the tread has worn to meet those indicators, then ...

As a result, tires have a TWI (Tread Wear Indicator) that shows when a tire is worn out. Some manufacturers have introduced new, simpler, and more precise indicators. The TWI is a long-used ...