Shimmy in the front end....

[casaleenie]

Need some ideas as to where to start in correcting a shimmy in the front end...
Shimmy in front at between 62 and 69 mph....
can cruise a 60 all day with no problem/can cruise at 70 all day also.
Had both T/A radials (15") replaced about two months ago and it took most of the shimmy away but now I'm back in the same boat..
Took it back to the dealer today and he starts talking transmission, drive shaft, rear end... etc... I said that's always a possibility but past experience tells me to start with the tire balancing..
They balanced to tires again and I talked the mgr. into taking a ride with me.. (it wasn't hard to talk him into it)Now he and I are best friends and he has ordered new tires for the car again...
However, I'm not sure that it will solve all the shimmy problems...
What else should I consider when trying to solve the problem... If tomorrow the problem is the same I'll let you know... The wheels are Compomotive three piece... Possibily a problem with them???


AL

[Brent]

I agree with you on the driveshaft,trans, and rear end not being the problem. They could cause a vibration but not a shimmy in the fromt end of the car. Have you jacked up the front of the car and checked play in the wheel bearings? Pull the dust cap off and remove the kotter pin. While spinning the tire tighten the nut and see how much movement you get. Make sure you spin the wheel as you do this you should not seat a bearing in a race unless you are turning it. If that is tight I would work my way from the wheel to the steering wheel checking for movement on every joint and rod end in the steering assy. If nothing shows up you could have the wheels checked.

Good luck,
Brent

[Brent]

I agree with you on the driveshaft,trans, and rear end not being the problem. They could cause a vibration but not a shimmy in the fromt end of the car. Have you jacked up the front of the car and checked play in the wheel bearings? Pull the dust cap off and remove the kotter pin. While spinning the tire tighten the nut and see how much movement you get. Make sure you spin the wheel as you do this you should not seat a bearing in a race unless you are turning it. If that is tight I would work my way from the wheel to the steering wheel checking for movement on every joint and rod end in the steering assy. If nothing shows up you could have the wheels checked.

Good luck,
Brent

[eliminator]

I am having similar results "Shimmy", mine starts at 61 MPH through around 68 MPH. I had my BFG tires rebalanced, I have adjusted my wheel bearings, and checked my Trigo wheels. I had the car aligned with 125 miles on it and I am going to have it aligned by another person, have 600 miles on it now. I changed tire pressure and that did help the ride and the shimmy some. Not as bad but still have it. I am in the process of going over all the bolts on the whole car, front - end first. Will keep you advised of the progress.

Eliminator

[eliminator]

I am having similar results "Shimmy", mine starts at 61 MPH through around 68 MPH. I had my BFG tires rebalanced, I have adjusted my wheel bearings, and checked my Trigo wheels. I had the car aligned with 125 miles on it and I am going to have it aligned by another person, have 600 miles on it now. I changed tire pressure and that did help the ride and the shimmy some. Not as bad but still have it. I am in the process of going over all the bolts on the whole car, front - end first. Will keep you advised of the progress.

Eliminator

[GeorgiaSnake]

Have you guys had your wheels spun without tires to check for runout? Are you having the tires balanced while mounted on the car? Just my 2 cents worth.

Randy

Unique 289 FIA
Southern Automotive 396
Team III 16's
Brilliant Silver

[GeorgiaSnake]

Have you guys had your wheels spun without tires to check for runout? Are you having the tires balanced while mounted on the car? Just my 2 cents worth.

Randy

Unique 289 FIA
Southern Automotive 396
Team III 16's
Brilliant Silver

[creeper]

From what Alan told me ,the shimmy is common, he told me they spent approx. and hour balancing my tires to perfect. He also told me to expect it if the wheels are not balance properly. I've found that many guys don't know how to high speed balance tires. They don't put the weights in the exact position. You might want to look for a location that has the new balancing machines. The new machines put a load on the tires, creating a real load situation , then they balance them. The 65 mile per hour shimmy is common. You could always have the tires shaved back to round.


http://www.miata.net/garage/65_mph.html

Wooohoo, rain stopped in the NE and was able to put some miles on....LOL[^]

[creeper]

From what Alan told me ,the shimmy is common, he told me they spent approx. and hour balancing my tires to perfect. He also told me to expect it if the wheels are not balance properly. I've found that many guys don't know how to high speed balance tires. They don't put the weights in the exact position. You might want to look for a location that has the new balancing machines. The new machines put a load on the tires, creating a real load situation , then they balance them. The 65 mile per hour shimmy is common. You could always have the tires shaved back to round.


http://www.miata.net/garage/65_mph.html

Wooohoo, rain stopped in the NE and was able to put some miles on....LOL[^]

[weaver]

Tires that are within tolerance on a production car do not work the same on a car with no steering dampning, have the tire store balance both sides of the wheel, I know it doesn't look the best but it is the only way to get the shimmy out. We have had this problem for years as do other manufacturers, our FIA car had a bad shimmy with Trigos and we finally balanced both sides of the wheel and it is now smooth at all speeds. we covered the outside weights with aluminum tape and it hardly noticable. Also check the steering and make sure your joints are tight, this will cause a shimmy.

Alan

[weaver]

Tires that are within tolerance on a production car do not work the same on a car with no steering dampning, have the tire store balance both sides of the wheel, I know it doesn't look the best but it is the only way to get the shimmy out. We have had this problem for years as do other manufacturers, our FIA car had a bad shimmy with Trigos and we finally balanced both sides of the wheel and it is now smooth at all speeds. we covered the outside weights with aluminum tape and it hardly noticable. Also check the steering and make sure your joints are tight, this will cause a shimmy.

Alan

[casaleenie]

Thanks guys,

I've checked the bearings, checked to see everything was tight,Steering linkage is tight. This is my third set of T/A's on the front. Had the wheels spun without tires.
Left front Compomotive wheel was a little out but they didn't seem to think that was the problem... Had the rear wheels balanced along with the fronts today... Going to try the recommendation of Alan and get the weights to the outside... It's making me crazy... I'll take all these suggestions to the dealer tomorrow and get them rebalanced with weights on both sides....
Thanks a million.....

AL

[casaleenie]

Thanks guys,

I've checked the bearings, checked to see everything was tight,Steering linkage is tight. This is my third set of T/A's on the front. Had the wheels spun without tires.
Left front Compomotive wheel was a little out but they didn't seem to think that was the problem... Had the rear wheels balanced along with the fronts today... Going to try the recommendation of Alan and get the weights to the outside... It's making me crazy... I'll take all these suggestions to the dealer tomorrow and get them rebalanced with weights on both sides....
Thanks a million.....

AL

[casaleenie]

I'm heading to get the wheels done as per Alans reccommendation...
Wish me luck... I'll let you know how they come out....

AL

[casaleenie]

I'm heading to get the wheels done as per Alans reccommendation...
Wish me luck... I'll let you know how they come out....

AL

[Aggressor]

Casaleenie, My car exhibited a severe shimmy when I drove to the last Unique Homecoming. It occurred at around 45 MPH and got worse at speed. I had the wheels balanced only two days prior to the event so it seemed likely that balance was my problem. In Gadsden I went to a Ford quick service shop and was lucky to find a person very skilled in balancing to close tolerance. Evidently there is a spring within the centering cone on spin balance machines and if it is not removed for the larger rim/tires it will offset your balance. My wheels were tape/weight balanced on the inside as close to centerline as possible. - Aggressor

[Aggressor]

Casaleenie, My car exhibited a severe shimmy when I drove to the last Unique Homecoming. It occurred at around 45 MPH and got worse at speed. I had the wheels balanced only two days prior to the event so it seemed likely that balance was my problem. In Gadsden I went to a Ford quick service shop and was lucky to find a person very skilled in balancing to close tolerance. Evidently there is a spring within the centering cone on spin balance machines and if it is not removed for the larger rim/tires it will offset your balance. My wheels were tape/weight balanced on the inside as close to centerline as possible. - Aggressor

[casaleenie]

What a difference a day makes... I'm back in business... Tire Kingdom did some homework on their own and with the information from Alan Weather, it's fixed... The weights on the outside of the wheel look OK..
I'll try the aluminum tape to dress it up a little...
Thanks again- this forum is great....

AL

[casaleenie]

What a difference a day makes... I'm back in business... Tire Kingdom did some homework on their own and with the information from Alan Weather, it's fixed... The weights on the outside of the wheel look OK..
I'll try the aluminum tape to dress it up a little...
Thanks again- this forum is great....

AL

[rdorman]

Finally found a good balancer there Al! That shimmy centered some where around 62, to my knowledge, has never been solved by anything but a dynamic balance issue. The 'been there, done that school'. It is a shame to put weights on the outside of the wheel.
Rick

[rdorman]

Finally found a good balancer there Al! That shimmy centered some where around 62, to my knowledge, has never been solved by anything but a dynamic balance issue. The 'been there, done that school'. It is a shame to put weights on the outside of the wheel.
Rick

[GeorgiaSnake]

Rick I don't want to pick a fight here but what is wrong with weights on the outside. I have had several race cars and the weights were all over the place, covered with racers tape. Most of the Corbra replicas replicate what was a racing car and if you look at the pictures of the old originals you will see weights. I will put weights on the outside without hesitation if it makes the car drive better. Again no fight intended here just a comment and a weighty one at that.

Al, glad you got the shimmy under control. Chill has experienced the same thing and sent his wheels back - he still has a little "cowl shake" but no weights on the outside - his wheels look great though.

Randy

Unique 289 FIA
Southern Automotive 396
Team III 16's
Brilliant Silver

[GeorgiaSnake]

Rick I don't want to pick a fight here but what is wrong with weights on the outside. I have had several race cars and the weights were all over the place, covered with racers tape. Most of the Corbra replicas replicate what was a racing car and if you look at the pictures of the old originals you will see weights. I will put weights on the outside without hesitation if it makes the car drive better. Again no fight intended here just a comment and a weighty one at that.

Al, glad you got the shimmy under control. Chill has experienced the same thing and sent his wheels back - he still has a little "cowl shake" but no weights on the outside - his wheels look great though.

Randy

Unique 289 FIA
Southern Automotive 396
Team III 16's
Brilliant Silver

[JerryBP]

Just starting on our Cobra kit but my Pantera wheels have been
spin-balanced on the car so that the disk rotors, hub and all get balanced together.
This is the only way I know of that reakky works for high speed (140+).

Work in Progress Unique 427-9429 400hp 351C Tremec 5spd by Bruce, Greg & Jerry Porter

[JerryBP]

Just starting on our Cobra kit but my Pantera wheels have been
spin-balanced on the car so that the disk rotors, hub and all get balanced together.
This is the only way I know of that reakky works for high speed (140+).

Work in Progress Unique 427-9429 400hp 351C Tremec 5spd by Bruce, Greg & Jerry Porter

[excelguru]

I need to start visiting this site more often. I've had this problem for quite a while, myself. Alignment didn't help. Balancing (weights on inside) didn't help. I actually began to loathe using the interstate beacuse of the shimmy (mine happens at 70-75).

My next stop? ATS Performance in Columbia where they have first-hand experience with high speed cars. I remember one of their technicians telling me quite a while back that I would need weights on boths sides to correct my problem. Sounds like he was right.

Of course, I'll have to wait for the rain to stop... :(

Keith :)

My "homepage" is my photo album.

[excelguru]

I need to start visiting this site more often. I've had this problem for quite a while, myself. Alignment didn't help. Balancing (weights on inside) didn't help. I actually began to loathe using the interstate beacuse of the shimmy (mine happens at 70-75).

My next stop? ATS Performance in Columbia where they have first-hand experience with high speed cars. I remember one of their technicians telling me quite a while back that I would need weights on boths sides to correct my problem. Sounds like he was right.

Of course, I'll have to wait for the rain to stop... :(

Keith :)

My "homepage" is my photo album.

[rdorman]

Randy, what is there to fight over? Personally I don't like the weights on the outside. If I had to though, I would!
Rick

[rdorman]

Randy, what is there to fight over? Personally I don't like the weights on the outside. If I had to though, I would!
Rick

[casaleenie]

I figure the payoff comes down the road with the weights on the outside.
I haven't shaken the car to death or put undue wear and tear on the suspension and body... I'll learn to live with the weights.. Sure is a pleasure to drive on the freeway not bouncing all over the place...
Thanks guys....

AL

[casaleenie]

I figure the payoff comes down the road with the weights on the outside.
I haven't shaken the car to death or put undue wear and tear on the suspension and body... I'll learn to live with the weights.. Sure is a pleasure to drive on the freeway not bouncing all over the place...
Thanks guys....

AL

[excelguru]

Fixed it. Thanks, guys. The interstate is fun again.

Keith :)
Unique Motorcars (http://www.uniquecobrareplicas.com)
Southern Automotive (http://www.southernautomotiveengines.com)
Jodeco Auto Body (http://www.jodecoautobody.com)

My Photo Album (http://members5.clubphoto.com/keith355593/owner-429c-1.phtml)

[excelguru]

Fixed it. Thanks, guys. The interstate is fun again.

Keith :)
Unique Motorcars (http://www.uniquecobrareplicas.com)
Southern Automotive (http://www.southernautomotiveengines.com)
Jodeco Auto Body (http://www.jodecoautobody.com)

My Photo Album (http://members5.clubphoto.com/keith355593/owner-429c-1.phtml)