Still fighting an unacceptable shimmy at 60mph. I've swapped wheels and tires,switched fron to back,balanced,rebalanced and balanced again. The only thing I can find that is wrong is a VERY slight looseness in the right rear wheel bearing. Would this be enough to cause a full body shimmy at 60mph?
Any suggestions?
Mike

Also check alignment of all 4 wheels.

Once had a failing CV joint that felt like a tire balance issue.

But the sloppy wheel bearing needs fixing.

Get someone to drive alongside and get a look see. Is one tire/wheel out of balance the culprit or is it front end shimmy? Is the wheel/tire out of round? Jack up one rear wheel about 2" off the ground, chock the wheels and set the emergency brake (I had to add that part - I live in CA ) start the car and put it in 1st gear, place a 2x4 behind the spinning tire about 6" from contact then place a pencil or a popcicle stick on the 2x4 a slowly slide it towards the spinning tire. Once you get the pencil within a 1/2" of the tire it will be apparant if there exists an out of round situation. One of mine was 3/16" out. I had them trued after that. But I still had a vibration, albeit greatly reduced. I rotated the tires F-B, R-L and criss cross (it's OK,they were new) to what I felt was the lest vibration, then I began to rotate the wheel to rotor one bolt hole at a time. Didn't change a thing after I did the RF but the first time I rotated the left wheel/rotor one hole it smoothed out. It was a 3 month ordeal. And all because I was a cheap ass and didn't buy decent tires in the first place!

look for strange wear and/or bubbled tire separation

the hot summer brings out the best, both my older son and his friend had tire seperation in this heat... one completely failed, ripped a hole in his trucks floorboard

Also consider Tangerine Racing's Rear Wheel Hub Centering Rings. When Porsche made the front wheels hub centric, they left the rears alone. Installing these rings absolutely centers the wheels on the hub. They made a big difference in smoothness for my car.

Thanks for all the suggestions. I'll check Tangerine's website.
Anything else? What about that wheel bearing? Would it cause this?
Mike

Check your suspension bushings, balljoint looseness, etc. Also is your front wheel bearings adjusted properly?? How much play in steering rack ?? And as mentioned is alignment good ??

Jack / Jaxdream

Mike, just solved this on my car. Front wheel bearings were loose on both sides. No more shimmness even at 90 mph. I feel stupid for it taking so long to finally find that out.

I don't feel any looseness in the front wheel bearings when I have the front jacked up. I'll pull off the caps to make sure.
Thanks

I have little vibration at ~58 through 65 and think I will try this solve. I am guessing this is the issue I have. Just saw these reading yesterday

Lots of answers, maybe from some folks who know what year, what tires, what suspension, and what wheels you have. I say they must know, because you're getting answers based on almost no information. Not the best way to get your problem solved.

The Cap'n

OK...a little more information. The car is a 74 2.0liter. New Boge inserts and new Boge rear shocks with stock springs,factory sway bar,Mahle wheels.Brand new Khumo tires. I have had 2 wheels repaired for slight wobbles, and have balanced 5 times. I borrowed another guys' front wheels and that made no difference. I couldn't try the rears because my wheel bolts were too long for his steel wheels.
There is barely perceptible play in the right rear wheel bearing. I just checked the front bearings and they were too tight,I couldn't move the washer at all,so I loosened them slightly.
The car sets up a full body shimmy at 60mph. Good below that and good above that speed. CV's look good and shafts run straight.
What am I missing?
Mike

There you go; now the Cap't can solve it for you.

Do you have wheel locks? Original tie rods?

The Cap'n

Check the tie rods on the inside/streering rack location my OEM rubber ones were a tad sloppy and caused a shimmy at 165MPH!!!

OK I added 100MPH to the speed

I will replace them with turbo tie rods, when I stop being so lazy!!

Had the same problem. Drove me crazy. You know what fixed it? Belive it or not my tire pressure was way low! Low profile tires and did see it nor did anyone else.

Put in 10 lbs +- And yes it was only at 60 mph. Looks like my side walls were flexing a bit.

Why go to all that trouble? Just jack it up and set some solid object (2x4 works) 1/4 inch from the tire and spin it by hand.

If its coming from the front wheels, you'll feel it in the steering wheel. Rear end, you'll feel in your butt. A cv would vibrate way befor 60mph. I'm guessing tie rod ends or ball joints.

Cap'n...no wheel locks.Not sure about the tie rods,I've only had the car a few months.I had it on a lift at my mechanics shop and he thought everything looked good. Thanks everyone for the suggestions.
Mike

I have a high-speed shimmy as well. I replaced the tie rod ends, steering coupler, and sway bar bushings. Front end is nice and tight but the rear still has the symptoms.

I have a feeling it's caused by a combination of trailing arm bushings and wheel balance.

The rubber inner tie rod end is probably36 years old, because no one ever replaces the inner ends unless they're converting to "turbo" tie rods. Whether or not replacement will correct the problem, it's a conversion that truly fits in the "upgrade" category.

I agree with the earlier response that steering wheel vibration is usually from a problem in the front, and seat of the pants vibration is most commonly caused by a problem in the rear of the car. We see a LOT of CV joint related vibration in FWD cars, and theat's generally felt in the butt, not the steering wheel. However, the problem is most evident under light acceleration and light deceleration, not cruising at a set speed with no real load on the driveshafts.

The Cap'n

That's a reasonable question. 1 - I'm 60; screw spinning it by hand. 2 - I added the pencil part because of Murphy's Law. Trying to make it idiot proof so someone wouldn't lose a finger in case they couldn't read and did it from the front. 3 - I didn't mention that I also checked the tracking at the rim/sidewall to see if the wheel was bent from a slide into a curb.

Haha! I hear ya. I'm 61 and still r&r engines by myself, but its harder everytime. One of these days I just won't be able to do it anymore. The pencil was the part I understood.