Glossary

Tread wear indicator

Last reviewed: 2026-05-20

A raised bar molded into major tread grooves at approximately 2/32 inch depth. When the tread surface wears flush with the bar, the tire has reached the federal minimum for non-steer positions.

On steer axle tires for commercial vehicles, the federal minimum is 4/32 inch — higher than where the wear indicator appears. A visible wear bar on a steer tire means the tire is already below the legal commercial minimum.

Real-World Use

A driver spotting a wear bar becoming visible on a steer tire reports it to maintenance immediately — the tire has reached or passed the steer-axle removal depth under federal rules.

Reference Sources

Sources used for context and verification of regulatory thresholds, inspection criteria, and compliance references on this page.

Gov 49 CFR 393.75 - Tires (Electronic Code of Federal Regulations, reviewed 2026-05-20)
Ind CVSA North American Standard Out-of-Service Criteria overview (Commercial Vehicle Safety Alliance, reviewed 2026-05-20)

What to Pair It With

Read this term with the full tire sidewall, vehicle rating information, manufacturer documentation, and the actual condition of the tire.

This site is for general information only. It does not replace professional tire service, DOT compliance advice, tire manufacturer instructions, vehicle manufacturer recommendations, or fleet policy.