Degree of wear: When tire tread is worn almost to top of wear indicator point and tread groove depth is less than 16mm, tire should be replaced.
Lifetime: under normal conditions, tires can be replaced after 3-5 years of use. Each tire is clearly marked with date of manufacture. There are four numbers printed on sidewall of tire. The two digits represent year.
Mileage traveled. The mileage of urban paved roads is about 60,000 km, and danger of driving increases after exceeding this number of kilometers. In harsh road conditions such as dirt roads in suburbs and mountains, keep an eye on tires for scratches in market. Replace tires in advance.
Whether there is any injury: After surface of tire is clearly cracked, bulging, deformed, nailed, etc., it proves that metal coil inside tire has been deformed or broken, and must be replaced immediately. with no doubt.