Are snow tires useful?
Are you talking about snow tires or anti-skid tires? Snow tires should be tires with steel studs on the surface, and their use is prohibited on most domestic roads. . Presumably you are talking about anti-skid tires? Anti-skid tires have a certain effect, after all, they will not harden due to low temperatures. .
Generally speaking, the tires we use produce gripping ability by conforming to the small unevenness on the ground. However, when the temperature drops to about 0 degrees, ordinary tires will become hard (temperature The lower the tire, the harder it is). The hardened tire tread cannot fit the uneven road surface, and the gripping ability is also reduced a lot. The principle is the same as that of shoes with tendon soles, although they are quite wear-resistant. , but the beef tendon bottom also hardens as the temperature decreases, thus losing its ability to grip the ground, resulting in wrestling. . At about 0 degrees, the hysteresis effect of ordinary tires is reduced due to hardening, and the molecular adhesion and meshing effects caused by this will be simultaneously weakened. Therefore, the grip ability of ordinary tires in winter is greatly reduced.
Snow tires use a combination of natural rubber + polybutadiene rubber. This polybutadiene rubber can be said to be the most elastic and most low-temperature rubber at present. It has small hysteresis loss. The glass transition temperature can be as low as minus 105 degrees (vitrification is simply understood as hardening)! Therefore, the combination of these two natural rubber + polybutadiene rubber basically guarantees that the tire will not "vitrify" no matter how cold the environment is. This is the main reason why anti-skid tires are anti-skid. As for other textures and drainage channels Such things are considered auxiliary! Just like tendon-soled shoes, even if they are designed with a herringbone outsole, they will still be slippery in winter, because they become hard, and they will inevitably slip when they become hard!
As for the usefulness of snow tires, it depends on where you usually use your car. I live in Northeast China and Shenyang, and I drive a rear-wheel drive car. I have never changed to anti-skid tires in winter, because the snow removal in Shenyang is very intensive. I have to bear the snow to remove it. Generally, after the snow stops, the road surface is almost cleared! The snow removal work in other large cities in Northeast China is also very good, so generally you don’t need anti-skid tires when driving in the city! If the place where you live does not have enough snow removal, such as some towns or county-level cities, then it is still necessary to wear anti-skid tires in winter. Take the national highway between Nanzamu on the edge of Fushun and Hongtou Mountain as an example. It will be covered with ice all winter, and it won't even melt away until the end of April next year. In this environment, it is necessary to wear anti-skid tires!
In short, the usefulness of snow tires mainly depends on your environment and your driving skills. They are not mandatory! However, using anti-skid tires provides an additional layer of safety guarantee. As for the effect, I have not done any specific experiments. At a speed of about 40km/h, it can save about one and a half vehicle body lengths in braking distance compared to ordinary tires!