How deep should a sidewall cut be before replacing a car tire?

[VanJulianna]

Tires with sidewall cuts should be replaced promptly regardless of the depth of the damage. If a tire is cut, check whether the safety cords are exposed - if they are, the tire must be replaced immediately. If the cords aren't exposed, the tire may still be used for city driving. However, if the contact surface damage exceeds 4mm, the tire should be replaced as soon as possible, as both internal and external repairs pose potential risks. The functions of tires include: 1. Transmitting driving force, braking force, and steering force to enable vehicle operation; 2. Supporting vehicle loads; 3. Absorbing vibrations and impact forces during driving to prevent damage to automotive components. Tire maintenance methods include: 1. Regularly checking tire pressure; 2. Inspecting tires for bulges, cracks, cuts, nail punctures, or abnormal wear; 3. Removing foreign objects like stones, metal pieces, or nails from tread grooves; 4. Performing wheel alignment or tire balancing.