Are the shocks knee action or lever shocks? I understand that leakage of the hydraulic fluid is the best way to tell if the lever shocks are any good.
I had a vibration at 50 mph coming from the rear. I found it on the balancing machine but I also jacked the rear end up a few inches and ran it in gear. You could see the tire was out of shape by the way it jumped up and down.
Some balancing machines use the wheel center hole to mount the wheel/tire on the machine. If your center hole is out of line or elongated you could get a faulty reading. Try to find a balancer that has the fingers which go thru the lug nut holes.
