At what severity must a sidewall cut on a tire be replaced?
3 Answers
Tire sidewall cuts generally require replacement when the size reaches approximately 4 millimeters. Below are precautions for tire usage: 1. Regularly correct wheel balance: Excessive wheel imbalance will cause high-frequency oscillations during high-speed driving, leading to uneven tire wear and compromising driving safety. After tire repairs, dynamic balance testing and adjustment should be performed, with the single-side dynamic balance test value not exceeding 40 grams. 2. Perform regular tire rotation: To ensure even wear across all tires on a vehicle, tires should be rotated every 5,000 kilometers, and a four-wheel alignment should be performed every 5,000 to 10,000 kilometers to prevent abnormal excessive wear. It is prohibited to install tires of different models or with significant wear differences on the same axle.
I've been driving for over 20 years, and a cut on the tire sidewall is something you really can't take lightly. If the scratch depth exceeds one or two millimeters or you can see the inner cords, you must replace it immediately. The sidewall is the thinnest part of the tire and bears all the support; if it cracks, it's prone to blowouts at high speeds, which is an extremely high risk. I once encountered this situation on the highway and was lucky to spot it in time and replace the tire. During routine checks, you can pinch the sidewall—if it feels soft or has bubbles, be alert. Don't skimp on tire replacement; safety comes first. Professional evaluations from auto repair shops or 4S stores are far better than our own guesses. Also, try to avoid curbs when parking daily to reduce damage.
For scratches on the tire sidewall, it depends: if it's just a shallow surface scratch that hasn't penetrated deeply, cleaning it up generally means it's still usable, but regular checks are necessary. However, if the cut is deeper or exposes internal cord-like structures, immediate replacement is absolutely required. Such damage can cause unstable internal pressure, and there are many cases of sudden blowouts while driving—don't gamble with your life. A quick test is to use a fingernail to gauge depth; anything over 2mm is a danger sign. Avoid overloading during normal use, and remember that tires typically need inspection/replacement around 50,000 km—investing in new tires is always better than risking an accident. This advice comes from hands-on repair experience.