I'd give road-force balancing a shot. Mine shimmies a little on the highway as well (after a standard balance) so I'm going to have it road-forced soon. I told the mechanic explicitly to road-force them but he said afterwards they didn't need it. I wasn't real happy with the guy. I've had good luck with road-forcing on all of my previous vehicles so I'm hoping it will hold true with my Bonneville. If it'* not that, I would agree with Rogue'* warped rotors suggestion--it'* possible but I'm betting on the wheel balance. Keep us informed. I'll probably run out and do it sooner if you post a good report.

i beg to differ, when my axle boot broke, the car shook like a mudderflubber due to wear in the CV..

you obviously wont feel it right away if the boot lets go, but ovetime, you will

Agreed, once all the grease is gone and time plays a toll on everything but initially when the boot is punctured (if its small) you can go for a long time without noticing it (unless you look under the hood often)

Ok, I'm still waiting for one of you fine gentlemen to tell me what ISS stands for.

Intermediate Steering Shaft

I too have the same model and year and the same problem. I have spent over $150 trying to balance the front end. I get a little bit of that with the rears too. My last attempt with a Hunter Roadforce was no better than a WalMart balance. The dealer said the tires showed too much "road force" to be balanced correctly so I replaced all 4 tires (Pirelli P Zero Nero) with Kuhmo 255-50'* (awsome tires) and did the Hunter Roadforce again. Crap! No change. The new tire folks threw in a free alignment with the tires. Then they said they could not align because I have two bad tie rods. The drivers side is definitely toast at 70K. The passenger side seems tight enough though. I hope that is the problem.... finally. The Bonne front end goes under the knife tomorrow. I'll let you know if the tie rod replacement helps.

Ted,
I see you're in Dayton, I'm in Cincinnati.....

I'm also taking mine in Wednesday for a complete inspection of the front end, I have a suspicion tie rods are playing a role in this thing. I'll lt you know

John

My car had a vibration at 65 mph as well with the original RSA'* on her. I got new Michelin MX4V'* and the problem no longer exsists. Two words: Better Tires! Better Balancing!

On a side note, I went to get my sc fluid changed during a recent oil change and when the guy opened the hex nut it sprayed out and burned his arm with that smelly stuff. He swore he'd never change another one again in his shop! I guess that fluid is pressurized when it'* hot.

Out of balance followup: Well, the new tie rods did not help the front end out-of-balance condition one iota. Funniest thing, you can feel it in the wheel but when you take your hands off the wheel you can not see it in the wheel. Most times the back end acts up too. It is kind of an oscillation. Like for 10 secs. it vibrates, then smooths out, then starts back up again.... back and forth kinda. It is not noticeable at all on rough concrete on either front or rear ends; only smooth surfaces. The tire dealer says he can't get the front end any better unless he places the weights on the outside of the rims too, but then he can't promise a cure. Currently the weights are not on the outside of the rims. Will this make a difference? On the last set it made no difference whether the weights were stick-on (out of sight) or exterior rim mount. Tire guy says the rear shocks may be the culprit. I say if the wheels and tires are in balance poor shocks would not make the rear end feel like out-of-balance condition. Shocks are not leaking and rebound about 1-1/2 times when I push down on rear bumper. I did recently replace the rear upper shock mounts cause they were showing signs of going south. That really made no difference in ride quality either.

on my 01, I had them rebalance and put the weights on the outside of the rims, and this did make a big difference in the vibration. Also, had the Intermediate Steering Shaft replaced Tuesday and man, what a difference. Vibration is almost completely gone, and it feels like a brand new car. The vibration is still there a little bit, but very tolerable now. Going to take it in for the road force balancing in a week or two and see if that eliminates it.