We can always see both arms tightening the tire wrench […]
We can always see both arms tightening the tire wrench with full strength, fearing that the arm strength is not enough, we still use our feet to step on it. This way, although it can be tightened very tightly and will not loosen, it will cause cracks in the screw due to excessive force. Long-term use may cause the screws to break. Many car owners know how to replace the spare tire, but there is still a problem that many people ignore, that is the torque of the wheel screws. The torque of wheel screws is a very unfamiliar concept to many car owners, but in fact this concept is very common. Basically every screw has a certain torque, especially the bolts used for assembly and tightening. The torque of the wheel is no exception.
However, we can always see non-standard actions of tightening the tire screws. It is true that the screw can be tightened very tightly without loosening, but it will be elongated due to excessive force, exceeding the design stress of the screw, and the internal cracks caused by excessive force on the thread will appear, and it will be used for a long time. Or sudden violent force may cause the screw to break. The hazard of the hidden danger of tire screws: The first problem is that there is a chance that the wheel will be thrown out. The more high-speed driving and violent bumps, the greater the pressure on the tire screws, and its own "health" becomes extremely important. There have been many painful cases caused by unqualified wheel hub screws. Therefore, the quality of a small tire screw is of great importance. Different models of different brands require different torques for the tires and wheel bolts.
The specific torques are generally indicated in the vehicle user manual that comes with the vehicle. According to the experience of Niugas technicians, the tire screw torque of general Mercedes-Benz, BMW, and Audi models is mostly 120~180Nm. When using a torque wrench to tighten the screw, set the torque value. When the torque is reached, it will automatically release the force. A "click" sound is issued. At the same time, it is very important that tire screws have requirements for manufacturing strength and material hardness. The general strength value of the quality standard wheel hub screws is above 10.9. That is to say, the tire screws are not capable of any one screw.
Don't change them at will because of the fancy appearance and novel style. This is the same as those that only have appearance and no quality. The hidden dangers of the inferior quality wheels are the same. There are old rumors: tire screws are reversed, that is, ‘tighten left and loose right’ so that they can run tighter as the wheel rotates. When is it all? Everyone has a car. This rumors should be over. Judging from the experience of these Mercedes-Benz, BMW and Audi cars that the Niugas technicians have contacted, they are all conventional "left loose and right tight". The reverse buckle is really what the rumors say. Don’t forget that the tires have two sides. If you run tighter, the other side will run looser. For car owners who have the ability to change tires by themselves, Niugas technician has a small The advice is to tighten the screws in a diagonal order when using the tire cross wrench in order to make the wheel hub and all the screws evenly stressed.