Maybe try driving the car at speed on a multi-lane highway, with a pair of friends driving "wingman". The passenger in the other car should observe all four of your wheels to see if any movement can be detected, then at least you have narrowed the problem down to one or two wheels, or not a wheel problem at all but something in the drive-train, like a out-of-balance drive shaft or a really bad rear axle.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC