With the top down and on a relatively smooth black top road, my '71 will act like it has egg shaped wheels at speeds between 25 and 35 mph. I have gone through it all, wheel and tire run out, balancing, brakes, drive shaft, rebuilt front end, frame stiffeners, new shocks, steering box, re balance the tires again etc... The fenders shake, the column wobbles and it all feels like it (the suspension and body) is going in different directions at the same time. You have to be driving to notice it from the feed back in the steering. The passenger is usually completely unaware. Is this just something I have to accept with an older convertible or can this low speed shimmy shake wobble nonsense be eliminated? At highway speeds or speeds above 35/40 there is no issue. On concrete roads it is hardly noticeable. I am tempted to install a steering stabilizer (horizontal shock absorber on the drag link) to see if it will help.