Front end\steering wheel shimmy

[MrWhipper]

Hello to all. I have a 1999 GT vert. Last year I swapped out the stock 17" rims for 18"x9" Saleens and I put Toyo 255x45x18 on them. Since I did this I have had a front end shimmy problem ever since. The problem lies between 45 and 60 mph. Tires have been replaced by Toyo once they have been balenced 4 times between the 2 sets. They have been rotated twice. Rims have been checked twice by two different people. The front end has been checked two times by different people. I have read in different forums that this not an uncommon problem and the problem lies with the lower control arms bushings being too soft from factory. Is this true? What do you think? Any suggestions? Thank you for your time.

By the way, this can is a pampered car. Run about 1000 miles per year, garage kept and I drive it gentley.

[J]

Sounds like there is something wrong with the rims... There is a way to balance your tires while applying ground pressure, sometimes this reveals different problems..

[MrWhipper]

Sounds like there is something wrong with the rims... There is a way to balance your tires while applying ground pressure, sometimes this reveals different problems..

How is this done and who does it? I do know that the rims were spun twice each and checked by different people at different times. They are true on a balancer.

[Finny]

You might need some rim spacers. Sometimes although the rims do fit the wheel well they dont fit well over the mountings themselves. IE even when you put 90 pounds or more through your bolts there is still space between your rim and the centre hub. I had a crazy shim going on for a few days after I put mine on, ordered my rim spacers (basically a plastic washer that slides over the hub before the wheel goes on) and it has reduced the shimmy in my wheels by at least 95% and the strength of the shimmy by another 50%. I can deal with a light wobble now and then.

Do not confuse these with big metal spacers to set your wheels out- those are garbage. Should just be a plastic ring to center the rims.

I believe the actual name of them is "Hub Centering Rings" or "Rim centering rings"

[MrWhipper]

You might need some rim spacers. Sometimes although the rims do fit the wheel well they dont fit well over the mountings themselves. IE even when you put 90 pounds or more through your bolts there is still space between your rim and the centre hub. I had a crazy shim going on for a few days after I put mine on, ordered my rim spacers (basically a plastic washer that slides over the hub before the wheel goes on) and it has reduced the shimmy in my wheels by at least 95% and the strength of the shimmy by another 50%. I can deal with a light wobble now and then.

Do not confuse these with big metal spacers to set your wheels out- those are garbage. Should just be a plastic ring to center the rims.

I believe the actual name of them is "Hub Centering Rings" or "Rim centering rings"

Wow, that sounds promising. Where can I get them at? Thanks.

[91GT347]

Have you had an alignment done ?

[rickyracer]

Find a good tire store that can balance the tires while they are on the car.

Can you take the wheel off and post a close up pix of the front/back center of the wheel?

With the age of your car, the bushings or ball joints could have a enough wear to couse your problem.

[MrWhipper]

OK, I am ready to pull my hair out and I can't afford to loose any more! THis is what I have, Front end had been checked out by a GREAT tech. All ball joints, tie rod ends, rack and bushings are as good as new. He miked the spindles and there is no wobble there. The allignment is very good and the wells\tries have been road force balanced. At the tire center that road force balanced them they checked the rims to see if I needed hub centric spacers and I do not. They assured me that if there was anything wrong with the tires or rims that road force would show it. The rims and tires are in great shape as per the 3rd tire center that worked on this situation. My steering wheel shimmy is still there between 45mph and 60 mph. I guess I am back to changing the lower controll arm bushings to urethane and changing the rack bushings to urethane. If you have any other ideas please let me know.

[91GT347]

Looks like you've done everything else.

[lftturn]

Wheel spacers will solve most of the problem. Also, when you go to a larger diameter or taller tire you will stretch your shocks/springs a tad bit taller. This puts the shock cylinder at it's vertical endpoint that can cause some highway vibration. Might check heigth with old tire size compared to new.

[94BlkGT]

Wheel spacers will not solve your problem. You have a Bad tire or a bad wheel, Since everything thing else has been checked out hose are your last 2 options. They could be out of balance.


Thing is alot of the times you can just move the tire around on the wheel and achieve a better balance and stop alot of the feeling that is transfering to your steering wheel.

[MrWhipper]

Thanks for your responses but like I said in post above, there is nothing wrong with the rims and tires. They just have been road forced balanced and if there was anything wrong with them the computer on the balancer would have picked it up. The rims do not need hub centric spacers. How does changing the tire and rim size affect shock travel height? It had on it 245x45x17's I put on it 255x45x18's.

[lftturn]

I talked to a friend of mine yesterday at an alignment shop. He said don't worry about shocks unless one is leaking. That's more critical in lift of two inches or more. He said the first two things he would check with your problem would be wheel bearings and driveshaft. He told me he went to wider and taller tires on an eighty five Mustang once and the driveshaft was out of balance. He said a U joint going bad can give you a little vibration at highway speeds also.

[lftturn]

P.S. Did you try swapping tires from front to back to see if problem was the same or worse?

[MrWhipper]

P.S. Did you try swapping tires from front to back to see if problem was the same or worse?

Yes, swapped front to back, shimmy the same, Toyo gave me new tires, shimmy the same. If there is a problem with the u-joints or drive shaft, would it shake the steering wheel? My understanding (which could be wrong) is no....

[lftturn]

I put an aluminum driveshaft in an old Camaro years ago and it was out of balance. I got a shimmy at 70 mph on highway. My friend was thinking a front U joint going out would cause highway shimmy if front end parts and wheels check out ok. I take it you haven't changed the toe in or camber, right? Does it do it on different road areas? This has become personal now. lmao. Good luck.

[Nicoleb3x3]

I've been suffering with this kind of problem for YEARS and replaced just about everything in my front end except maybe the control arm bushings...I'm going to try road force balancing in a last ditch effort to try and fix it before doing bushings.

I've done the following things to try to fix my issue which occurs most at 74mph and seems better when I go faster:
ball joints
tie rod ends
alignments
new tires


those hub centering spacer things sound like a good idea...I've never heard of them

[Nicoleb3x3]

hey lftturn, with the driveshaft...wouldn't you be able to tell it's not the front? My wobble seems like the front of the car for sure...but could it still possibily be the driveshaft?

[gunner_501]

lft has a pint there .. if the front universal is going it will shake the tranny and motor and sometimes make if feel like the front end .. I had that problem in a 68 Stang and when I crawled under it the front universal was about to fall out so I changed it and the shimmy was less but still there so the next idea was to rotate the driveshaft 180 degrees and that solved the problem. Don't know if this is your problem but it's worth a look and looking is cheap. Also if you have to change it get one with a grease fitting .. my original one didn't have one and that was part of the problem I'm sure.

[lftturn]

I went through all the stuff you guys did and a friend at the track told me to change the front U-joint. Changed both and had the driveshaft balanced. It went away. Bein' an old Camaro I don't know if that made a difference.

[lftturn]

Only other thing I had once was a wheel bearing wasn't seated firmly in my '65 Mustang and it wobbled some on the highway.

[MrWhipper]

OK, I will check the u-joints. I will post with my results.

[MrWhipper]

I put an aluminum driveshaft in an old Camaro years ago and it was out of balance. I got a shimmy at 70 mph on highway. My friend was thinking a front U joint going out would cause highway shimmy if front end parts and wheels check out ok. I take it you haven't changed the toe in or camber, right? Does it do it on different road areas? This has become personal now. lmao. Good luck.

The front end alignment is in the center of factory recommendations. Road type does not make a difference. The thing that is weard is that it can come and go a bit.

[Burmman]

Wow I just went through this. I have a plain jane 96 V6 car I cahnged out the factory rims for a set of aftermarket uni-lug 18's and they went on fine I thought great now this looks cool also. So I drove around for a few day back and forth to work. Nothing over 35 mph. Then decided to go on the highway and from about 45-60 I thought the wheel was going to shake off the car. I had the rims checked and wheels balanced also rotated the wheels. Damn I was going crazy. So a friend had a set of 17's also uni-lug and he works at a local shop I told him to fix the damn thing and I would trade rims and tires. So he did. It all came down to me being stupid and trying to use my factory lug nuts the didn't space the rims properly. So now I'm out some nice 18's but my car doesn't shake anymore. So I'm not sure if that is your problem but it was mine.

[MrWhipper]

Wow I just went through this. I have a plain jane 96 V6 car I cahnged out the factory rims for a set of aftermarket uni-lug 18's and they went on fine I thought great now this looks cool also. So I drove around for a few day back and forth to work. Nothing over 35 mph. Then decided to go on the highway and from about 45-60 I thought the wheel was going to shake off the car. I had the rims checked and wheels balanced also rotated the wheels. Damn I was going crazy. So a friend had a set of 17's also uni-lug and he works at a local shop I told him to fix the damn thing and I would trade rims and tires. So he did. It all came down to me being stupid and trying to use my factory lug nuts the didn't space the rims properly. So now I'm out some nice 18's but my car doesn't shake anymore. So I'm not sure if that is your problem but it was mine.

That is interesting. These rims are made just for Mustangs and came with their own lug nuts but, hmm.