I was told the yellow dot on the side wall of a tire should be aligned with the valve stem. My new tires have a yellow and red dot, what does that mean?
The yellow dot normally indicates the lightest point on the tire and is aligned with the valve stem. The valve stem is normally the heaviest point on the wheel. The red dot is more complex. If the tire has both, ignore the yellow dot. The red dot is basically the point of maximum road force variation, first harmonic. While not exactly, this might be thought of as the stiffest point in the sidewall. Some steel wheels have a dimple to mark the lowest spot in the wheel. If so, the red dot aligns with the dimple. If not, or with aluminum wheels, it is placed at the valve stem.
