Sidewall Damage Checklist

Serious sidewall damage includes cuts that penetrate to the cord layer or deeper, bulges or bubbles in the sidewall (which indicate internal structural failure), impact breaks, separations between the belt and casing, and any repair that does not meet industry standards for the damage location. Surface-level scuffs or abrasions that do not expose cord material are less immediately serious but should be monitored. When in doubt about how deep a cut goes, get professional evaluation.

Sidewall repairs are strictly limited. The standard repair zone for commercial truck tires is the crown — the tread area — not the sidewall. Most sidewall damage is not repairable to a level that restores full service safety. Cuts that penetrate to the cords, bulges, and separation damage in the sidewall typically require tire removal from service. Get professional evaluation before making any decision to keep a sidewall-damaged tire running.

A sidewall bulge indicates a separation or break in the internal structure — usually a cord layer — that allows the casing to flex outward in an unsupported area. This is a serious condition that can precede rapid failure. The tire should be removed from service immediately, not reinflated or driven on while waiting for a decision. A tire with a confirmed sidewall bulge is not safe for continued operation.

Ozone cracking — the fine surface cracks that appear in rubber exposed to UV, ozone, and heat over time — ranges from cosmetic to serious depending on the depth and extent. Surface-level crazing or hairline cracking that does not penetrate the rubber below the surface is generally not an immediate out-of-service condition, though it indicates tire aging and warrants monitoring. Deep cracks that reach the cord layer or that have significant width are a different matter — cord exposure is an out-of-service condition under 49 CFR 393.75 and a CVSA out-of-service criterion. When cracking depth is uncertain, a qualified technician should evaluate the tire.

Record the vehicle unit number, tire position (steer left, drive right outside, etc.), the nature of the damage (cut, bulge, cracking, scrub), the approximate size and location on the sidewall, and whether the tire was taken out of service or left in service with a note for maintenance review. Photographs taken in good light with a ruler for scale are far more useful than a written description alone. If the tire was left in service, note the condition at the next inspection to track whether the damage is progressing. A signed entry in the DVIR (Driver Vehicle Inspection Report) creates a maintenance record that documents both the finding and the disposition decision.