Thanks to all who helped me solve the 55-60 shimmy problem. After many balancing acts and bushing jobs, the final attempt at installing Hubcentric Rings (a $22 job) solved the problem and my 90 535i 5speed rides like brand new on the highway. The wheels were e39 on an e34, a very very slight difference in hub diameter but amazingly it did the trick. You guys are good! Thanks.