Wear of the outer edge If you look along the driving direction, the outer edge of the tire has great wear, indicating that the tire is often in a state of insufficient inflation, that is, insufficient pressure. If possible, inflate according to the "expressway" specification, that is, 30,000 pa more than the normal specification. It should be noted that the lack of inflated tires is very beneficial to driving in rainy days, and the grip on the ground will be obviously weakened. Bump and ripple wear If bumps are found on both sides of the tire landing site and there are ripples around the tire, it means that the shock absorber, bearing and spherical coupling of the automobile are seriously worn. It is recommended that you check the wear of the suspension system and replace the worn parts before replacing the tires. Otherwise, even changing the tires will not help. Once the pattern of a tire with uniform appearance is ground dry, it means that the life of the tire has been exhausted and it must be replaced. In addition, the pattern also has the function of draining the road surface, so it is an important link to adhere to the grip of the car. If the wear has reached the standard depth of tire tread (generally 1.6 mm, and the tire with a width greater than 175 mm is 2 mm), it should be replaced. If it is found that the central area of the tire landing site is seriously worn, it means that the tire is often inflated. Be sure to check whether the pressure gauge is accurate and adjust the pressure. It should be noted that tires need to be inflated only when driving at high speed or under heavy load. Most of the cracks in the front of the tire are due to poor maintenance, or driving on stony roads and construction sites, so that hard objects come into contact with the tire and the inner layer of the tire is damaged under heavy pressure. Action should be taken immediately. If the tire is not repaired properly, it should be replaced. The inner side of the tire is worn and the outer edge is burr-like. What is rare is that the suspension system of some old cars is poor, which makes the whole car deeply trapped. This shows that the tire is deformed and the symmetry of the two tires is affected. If conditions permit, it is best to replace all accessories such as shock absorbers and spherical couplings. But if the cost is too high, I suggest you consider asking a professional repairman to adjust the angle of the front axle and tire first.