I know some tire manufacturers put a dot on the heavy side of the tire on the sidewall and you're supposed to mount it opposite of the valve stem.
I think there is a lot of misinformation about the dots. Every article I've read states dots should be mounted nearest the valve stem, not away. One article stated the difference between a yellow & red dot is yellow marks the light spot of the tire, the other is marking the highest spot of tire (out of round)...then it said if the red dot is present, it is prioritized over yellow & to put at the valve stem.
As mentioned in the article posted by Max Midnight.. the Dot is the LIGHTEST part of tire.Everything I have heard is the dot is nearest the valve stem .