How long does it take to change a car tire? There are six evaluation criteria. If at least one of criteria is met, tire must be replaced.
Firstly, each tire has a tread groove, and there are raised squares in tread groove. Different tires may have different square shapes, but this does not affect observation. As long as tire pattern is worn to same level as raised square, tire will not only affect braking stroke, but also increase risk of tire burst, so it must be replaced at this time.
Secondly, there are 4 digits on tire indicating date tire was manufactured. The first two digits are week number, and last two are year. For example, number of this tire is 4220. , which means that this is 42nd week of 2020. Tires are rubber products and will age. Generally, they need to be replaced after 5-6 years, so we have to base on production date of tires. After five to six years, even if tires are not very worn, they should be replaced, but there is a process aging. Five to six years is not a hard target. If you work at high speed for a long time, it is recommended to replace it as soon as time comes. After all, high speed tire blowout is quite dangerous. But if your car only travels year-round to and from work within city, then it doesn't matter if you delay it for a while before changing it, but there is a minimum period of no more than 8 years, even if it is a new tire, which has never been used, it cannot be used after 8 years.
Thirdly, there is swelling on tire. Typically, this is a problem with layer. The risk of tire burst is very high. No matter how long pattern is worn and how long it has been used, it should be replaced immediately. If a bulge appears on inside of a tire, you won't notice it if you don't pay attention. If it occurs in summer, it's high tire burst season. Be sure to check your tires regularly to make sure there are bulges.
Fourthly, if side of tire is punctured, there is no point in repairing tire, in this case it remains only to change tire.
Fifth, if punctured tread diameter exceeds 6 mm, tire does not need to be repaired, so it is recommended to replace it immediately.
Sixth, different brands have different requirements for number of tire repairs. Smaller tires are allowed to be repaired only once, and larger tires are allowed to be repaired 4 times, and each tire has its own requirements. For example, Prism Pass, distance must be greater than 40 cm, if it is not met, tire is beyond repair. However, Michelin requires that central angle be greater than 90 degrees. What does this mean? Divide tire into 4 equal areas, and there cannot be two tire repair points in same area. Of course, manufacturer's requirements must be quite strict, and on weekdays we do not pay much attention to this, however, if the tire has been repaired more than 4 times, stop repairing and replace it.
Okay, if you think this is right, like it, and if not, see you in comments. Finally, question is, what other circumstances do you think should change tire? Follow me and learn some useful automotive knowledge every day!