How deep does a sidewall cut require tire replacement
2 Answers
If the contact surface is damaged by more than 4mm, the tire must be replaced. Below are the tire replacement criteria: 1. If the radial ply is damaged, the structural integrity of the entire tire cannot be guaranteed. The tire should be replaced immediately; otherwise, a blowout may occur at any time. 2. Visible cuts that may exceed 4mm in depth require immediate tire replacement to prevent blowouts. 3. Scratches caused by blunt objects that result in uneven surfaces with debris like small stones inside the cuts necessitate prompt tire replacement. Below are common methods for repairing tire sidewalls: 1. Cold patch repair: Simple to perform but not durable, especially for areas of the sidewall that frequently bear pressure. It tends to peel off over time. 2. Hot patch repair with vulcanized rubber: Ensures complete adhesion between the patch and the tire. However, the heat may damage the tire's cord layers, making it unsuitable for sidewall repairs. 3. Mushroom plug repair: Effective for small sidewall punctures without causing significant damage to the cord layers. Typically used for sidewall holes under 5mm in diameter. For severe sidewall cuts, replacement is recommended.
I once personally experienced a tire blowout on the highway, which was caused by a sidewall scratch that I had overlooked. Since then, I've developed a habit of regular inspections. Generally speaking, if a sidewall scratch exceeds 2mm in depth or exposes the inner cord layer (those white threads), the tire must be replaced immediately. The sidewall is the weakest part of a tire and bears tremendous pressure. A small scratch can potentially cause a blowout during high-speed driving, especially when turning or going over bumps—don't take chances with safety. I recommend visiting a professional tire shop immediately for an inspection, as they use specialized tools for more accurate measurements. Also, when parking daily, avoid getting too close to curbs to reduce the risk of scratches.
