In summer, many car owners are most concerned about how to use explosion-proof tires. According to statistics, about 1 / 3 of traffic accidents on expressways are caused by tire failure, and the most important one is tire burst. As a result, the knowledge about summer explosion-proof tire emerges in endlessly. It is said that reducing the tire pressure can prevent the tire from exploding. It is also said that filling nitrogen can prevent the tire from exploding?

When it comes to summer explosion-proof tires, the first thought that many people have in mind is usually to reduce the tire pressure. Because everyone has learned the principle of thermal expansion and cold contraction. If the air pressure in the tire is too high when heated, the tire will burst easily. Therefore, many car owners will naturally lower the tire pressure by 0.1-0.2bar after entering the summer. However, this seemingly reasonable method is actually counterproductive.

Because there are a lot of steel wires inside the tire to hold the whole tire. When driving under the condition of insufficient tire pressure, due to the irregular deformation of the tire, the steel wire inside the tire is constantly deformed. The result of the continuous deformation of the steel wire is that the temperature of the steel wire rises sharply, and it is easy to fracture. In addition, with the increase of tire temperature during driving, the possibility of tire burst will increase. Increasing the tire pressure by 0.1 or 0.2 bar from the normal value can effectively reduce the deformation and fracture of steel wire in the tire caused by tire deformation, thus reducing the possibility of tire burst. Therefore, reducing tire pressure is not reliable!

Nitrogen filling is also considered as a "good" method for summer explosion-proof tire. Because nitrogen is an inert gas, the molecular free path is larger than that of oxygen, and the permeability in rubber is low. Therefore, the decrease rate of tire pressure is greatly reduced and the time to maintain normal tire pressure is increased. At the same time, when the temperature changes, the volume expansion of nitrogen is much lower than that of air containing moisture, so the probability of tire burst is reduced.

However, we did an experiment in which the left and right tires of the same car were filled with nitrogen and air respectively. Then, the tire pressure and temperature are recorded every 10km. The final result is that the characteristics of "low thermal expansion coefficient, low thermal conductivity and slow temperature rise of nitrogen" are not obvious in practical application. Therefore, it is not advisable to fill the tire with nitrogen in summer to prevent tire burst.