I believe many car owners have had the opportunity to change their spare tire on their own, but the choice of the support point for the jack is mostly based on the feeling, and the correct support point selection is not clear. There are dedicated support points at the bottom of the car body to support the jack. The support points for household cars are usually located on the inner side of the side skirt, similar to the two fins on both sides of the chassis, about 20 centimeters behind the front wheels and about 20 centimeters in front of the rear wheels. This fin protrudes from the chassis steel plate and can withstand relatively high pressure. If the jack is supported on the chassis steel plate, it is likely to cause unnecessary damage to the chassis. In addition, supporting on the lower arm of the suspension is also incorrect operation. If the jack slips and the vehicle falls off, the chassis and jack will be damaged. Many household cars have a split arm jack structure that needs to be connected to a matching wrench and sleeve for rotation. Therefore, during the lifting process of the jack, the force should be uniform and should not be too fast or too strong.