What do the small circles on tires mean?
3 Answers
Red dots indicate the position of maximum longitudinal rigidity on the tire. The yellow hollow dot is called the tire light point mark, indicating that this position is the lightest part of the tire circumference. When replacing the tire, this part must be aligned with the heaviest position of the valve on the rim for installation to ensure optimal wheel balance during driving. The main functions of tires include: 1. Supporting the vehicle: Supporting the entire weight of the vehicle, bearing the load of the car, and transmitting forces and moments in other directions. 2. Enhancing vehicle performance: Transmitting traction and braking torque to ensure good adhesion between the wheel and the road surface, thereby improving the vehicle's power, braking, and passability; working with the vehicle suspension to mitigate impacts during driving and dampen resulting vibrations. 3. Ensuring vehicle safety: Preventing severe vibrations and early damage to vehicle components, adapting to high-speed performance while reducing driving noise, and ensuring driving safety, handling stability, comfort, and energy efficiency.
I've run an auto repair shop for twenty years, and the little yellow dot on the sidewall of a tire is actually a mark indicating the lightest point of the tire. This thing is professionally called the light point mark, just like how an egg has a lighter end. During installation, this dot should be aligned with the valve stem because the valve stem is the heaviest part of the wheel. Pairing them this way reduces the number of balancing weights needed for dynamic balance. As for the little red dot? That indicates the point with the strongest rigidity of the tire. If you notice the mechanic hasn't aligned this yellow dot when changing tires, it's best to remind them to adjust it, otherwise the steering wheel may vibrate at high speeds. By the way, new tires all have these colored marks, but they might wear off after some time.
Previously worked in a tire factory as a quality inspector. These small dots are actually positioning marks from the vulcanization process. On the assembly line, the red and yellow dots are used to locate the internal steel belt splice position, similar to cutting marks on clothing. The yellow dot indicates the static balance point, which has minimal impact on regular passenger cars, but racing tires require precise pairing. Nowadays, some high-end tires use laser engraving instead of paint dots because chipped paint affects aesthetics. It's recommended to check the inner side of the wheel hub for excessive lead weights one week after tire replacement—if more than three blocks are stuck, it indicates poor balancing.
