Glossary

Ozone cracking

Last reviewed: 2026-05-20

Surface cracking of the tire sidewall rubber caused by prolonged exposure to ozone, UV light, and weathering. Fine cracks typically appear in the sidewall and shoulder area, running perpendicular to the direction of deflection. Superficial surface cracks may be cosmetic; cracks that open under flexing or penetrate to the cord layer are a structural concern.

Ozone cracking is more common on tires in outdoor storage or on vehicles parked outdoors for extended periods. Regular flexing during normal service slows ozone attack.

Real-World Use

A fleet pulling trailers out of long-term outdoor storage finds significant sidewall cracking on the tires — a professional inspection determines which tires have cracking limited to the surface and which have cracks deep enough to require removal.

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.