Just put new rubber on my car. A buddy noticed the red and yellow dots on the sidewall, and said his new tires had the same thing. What are these for? Spin balancing reference points? Any tire people know?
Typically, a yellow dot indicates the lightest spot on the tire, so you’d want that aligned with the valve stem, usually the heaviest spot on the wheel.
The red dot is new to me, but apparently represents the high point of the tire, which you’d align with the low point of the wheel. I think this pair of marks is less common, but if you have a red dot and clear indication of the low part of the wheel, that pair takes precedence over the yellow dot.
First, if the tire has a red dot, the yellow dot is ignored! The red dot is then lined up with either the “low point dimple” (on steel wheels) or next to the valve stem on alloy wheels. Regardless of the type of wheel, if there is no red dot, the yellow dot is positioned next to the valve stem.
Why do the tire dots go where they do?
Simply put – the tire is a bit lighter in the area where the yellow dot is located, and a bit thicker where the red dot is located. On an alloy wheel, the valve stem marks the heavy point of the wheel. By matching the light point of the tire with the heavy point of the wheel it’s likely to give the best initial balance.
On a steel wheel the low point dimple marks the thinner part of the wheel – so it makes sense to match the red dot to the wheel dimple.
Thank you! Makes sense, and a quick look shows that indeed, the red dots are aligned with the valve stems.