
Whether tires with cracks need to be replaced depends on the specific situation: 1. If the crack length is less than 6 millimeters, it can be repaired at a shop; 2. If there are numerous small cracks, and the tire shows signs of aging, with countless small cracks at the bottom of the tread grooves or the tire side that are about to damage the tire body, the tire should be replaced promptly. Tires are circular elastic rubber products assembled on various vehicles or machinery for ground rolling. Tires are often used under complex and harsh conditions, enduring various deformations, loads, forces, and high and low temperature effects during operation. Therefore, they must have high load-bearing performance, traction performance, and cushioning performance. At the same time, they are also required to have high wear resistance and flex resistance, as well as low rolling resistance and heat generation.

Every time I wash my car, I carefully inspect the tires for cracks. Fine hairline cracks on the tread may just indicate rubber aging, but if the cracks exceed 1.5mm in depth or reveal the inner cord layers, the tires must be replaced immediately. This is especially critical for front tires, as blowouts can most easily lead to loss of control. Last month, I checked my neighbor's tires and found hair-thin cracks on the sidewalls, but they were deep enough to expose the steel belts. In such cases, even city driving is unsafe. The so-called 'hot patches' often recommended by repair shops are completely ineffective for these types of cracks. For safety's sake, it's always better to replace the entire set of tires.

After twenty years in auto repair, I've seen too many tire blowout accidents. If there's a bulge on the tire sidewall with radial cracks, don't hesitate to replace it. Last time, a customer wanted to save money and stretch it for another two weeks, only for the tire to tear apart on the highway. During inspection, insert a coin into the tread groove—if the crack depth can hide the edge of the coin, it's time for a change. Also, pay attention to the seams on the tire sidewall; cracks there are even more dangerous. Rubber has a shelf life of just five years, so even with low mileage, tires can still crack, especially on cars parked outdoors long-term.

In northern winters, special attention must be paid to tire cracks. Temperatures below minus twenty degrees Celsius can double the expansion speed of cracks. Last year, my tire had three hairline cracks, which I initially ignored. One morning during an emergency brake, I suddenly heard a 'pfft' sound. Upon getting out, I saw a three-centimeter-long split on the tire sidewall—the fine cracks had turned into a through injury. Low temperatures make rubber brittle, turning small cracks into major hazards in minutes. Now, I check the tire seams every two weeks, and if I find any bulges or hardening, I replace the tire immediately.

Those who frequently drive long distances know how crucial a tire pressure monitor is. Last week at a service area, I found a small stone lodged in the tire. After removing it, a 3mm deep crack was exposed. These kinds of cracks, narrow on the surface but wider inside, are the most dangerous as they continuously expand at high speeds. I always keep an air pump in my car, and if the tire pressure fluctuates abnormally by more than 10%, I immediately switch to the spare tire. By the way, spare tires also have an expiration date; the rubber starts to harden and crack after five years.

A car wash technician once taught me a simple detection method: if you feel the crack is sharp when scratching it with your fingernail, you should be alert. During the last , I noticed web-like patterns in the tire grooves, and the mechanic said this is a typical sign of aging. Pay special attention to the folded corners near the wheel hub on the tire sidewall – if Z-shaped cracks appear there, never delay. Additionally, when rotating tires, pay attention to the position of cracks; it's safer to move tires with outer side cracks to the rear. That said, the most worry-free approach is to replace the tires as soon as cracks are discovered.


