Another issue could be radial force variation/out of round. My '88 Mercedes wheels are "matchmarked", and I assume yours are too. The mark is a faint while "dot" about a quarter inch in diameter on the outside of the rim flange. The red dot on the tire should be aligned to the white dot on the wheel. This assures the minimum out of round and radial force variation for the assembly.

Many tire shops are ignorant of this practice, but the wheel marks can fade to the point where they are very tough to see.

If the tires were accurately dynamically balanced (weights on both the inside and outside of the wheel) on modern equipment in good working order, it could be a radial force variation or out of round condition. A slight out of round - say more than .020" can usually be seen with the tire spinning on the balance machine or just spinning the tires on the front end, but radial force variation in the tire cannot be visually diagnosed.

The Hunter 9700 can measure both wheel out of round and radial force variation and determine whether reindexing the tire on the wheel can improve the situation or whether the tire or wheel must be replaced to bring radial force variation down to the desired 10 pounds of less.

Duke