What are the red and yellow dots on the tires for?

Car tires and rims are high-speed rotating parts and have strict dynamic balance requirements. However, their mass distribution during the manufacturing process cannot be completely balanced, and there must be a certain deviation. Then we use solid red dots to mark the maximum point of radial vibration on the tire, which is the "heavy point" of the tire; use hollow yellow dots to mark the minimum point of radial vibration of the tire, which is the "light point" of the tire; use white dots To mark the minimum point of radial vibration of the rim, that is, the "light point" of the rim.
The hollow yellow dot is actually the light mark of the tire, indicating that this position is the lightest position in the tire. Car wheels are composed of three parts: tires, hubs and valves. The valve of the device on the wheel hub corresponds to the most important point on the wheel hub. When assembling the tire, the yellow marked position on the tire should be placed, that is, the lightest point corresponds to the valve, which can play a complementary role and distribute the weight. It tends to be balanced, and the bearing capacity of the entire wheel tends to be balanced, so that a better dynamic balancing effect can be achieved.
The solid red dot is the point of maximum longitudinal rigidity of the tire. Simply put, this solid red dot is the point where the tire vibrates the most when it rotates once. When the tire contacts the ground and rotates for one revolution, due to the difference in the mass of each part and the rigidity of the internal materials, the vibration force it endures at different angles is different. This phenomenon is called RFV. When the value of RFV is too large, the tire will vibrate when rotating. In addition to wear and tear, excessive tire pressure will also increase the dynamic load on the wheels. When driving at high speeds or on the bad road conditions just mentioned, the chance of a tire blowout will increase.
Therefore, this red dot is a reference for the manufacturer's quality supervision department during inspection. It is best to align this point with the lightest point of the wheel hub when the tire is installed, so as to reduce the vibration of the tire when rolling.
After marking in this way, it will be easier to install and dynamically balance the tires. For example, aligning the "solid red dot" of the tire with the "white dot of the rim" means aligning the "key point" of the tire with the "light dot" of the rim, so that the two can compensate for the balance as much as possible. Or aligning the "hollow yellow dot" of the tire with the valve of the rim, and aligning the "light point" of the tire with the "key point" of the rim can also compensate for the balance.