# I have a shimmy at 60mph



## LordAnarchy (Jul 3, 2009)

I have a 2004 Torrid red Goat with 71k on it. I have replaced tie rods, struts, strut mounts ( on both sides for all mentioned parts) and have put two new rims and tires after an 80mph blow out but i still have a shimmy just around 60mph. I have taken it to several mechanics who say the rest looks good but i think something might still be wrong. I have a bad differential but that gets replaced on the 12th with a spool and 3.91 gears. Do you guys think the shimmy could be from the blow out on the front end or the differential in the back? The shimmy is in the steering wheel but some of my mustang buddies blow half shafts and get a similer shimmy. P.S. i have also replaced one half shaft on passenger side.


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## GTO JUDGE (May 14, 2005)

LordAnarchy said:


> I have a 2004 Torrid red Goat with 71k on it. I have replaced tie rods, struts, strut mounts ( on both sides for all mentioned parts) and have put two new rims and tires after an 80mph blow out but i still have a shimmy just around 60mph. I have taken it to several mechanics who say the rest looks good but i think something might still be wrong. I have a bad differential but that gets replaced on the 12th with a spool and 3.91 gears. Do you guys think the shimmy could be from the blow out on the front end or the differential in the back? The shimmy is in the steering wheel but some of my mustang buddies blow half shafts and get a similer shimmy. P.S. i have also replaced one half shaft on passenger side.


You're certain the tires are properly balanced? Double check the glue on weights on the inside of the wheels to make sure you didn't lose any. Car aligned both front and back? New tires? If one is out of round this could contribute to some shimmy. How bout the drive shaft? If the shaft is out of balance you could get some wobble as well.


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## svede1212 (Nov 1, 2005)

GTO JUDGE said:


> You're certain the tires are properly balanced? Double check the glue on weights on the inside of the wheels to make sure you didn't lose any. Car aligned both front and back? New tires? If one is out of round this could contribute to some shimmy. How bout the drive shaft? If the shaft is out of balance you could get some wobble as well.


good points but one overlooked often is the wheel lugs torque. if they're just tightened down willy nilly or even worse with an impact it can warp the aluminum wheel causing the problem. i'd try loosening up all of the lug nuts and torquing them down to the proper torque. the method is 70#s on the first pass and then 100#s on the second doing it in a star pattern (every other one). go back around again and recheck


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## fergyflyer (Apr 18, 2005)

svede1212 said:


> good points but one overlooked often is the wheel lugs torque. if they're just tightened down willy nilly or even worse with an impact it can warp the aluminum wheel causing the problem. i'd try loosening up all of the lug nuts and torquing them down to the proper torque. the method is 70#s on the first pass and then 100#s on the second doing it in a star pattern (every other one). go back around again and recheck


Wow, 

I thought I was the only one anal enough to do this. First thing I do when I get home from a repair shop that had the wheels off is loosen my lug nuts and retorque. I've had wheel vibration issues and brake pulsation from lug nuts being improperly torqued. I also come back about 50 miles later and check them.

OP,
Try going to a place that does roadforce balancing and tire matching. You may have a tire that isn't matching with a wheel and needs to be rotated on the wheel or moved to another wheel. Also the roadforce balance will tell you if you have a bad rim or a bad tire which is possible with a new rim and tire from the blowout.


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## LordAnarchy (Jul 3, 2009)

*Suggestions well noted.*

All the tires are the same but they were put on by a run of the mill tire place and i had the front and back aligned with one of those laser systems. I will try the 70/100 steps, check my weights and look into the roadfroce balancing. To be honest i had never heard of that before. But how do i check the balance on the drive shaft? can they do that at a frame shop or is this something i can do at home? Also are the front ends on these cars prone to have problems of any kind? I know, i have a lot of questions sorry. just worried. been only driving it 5k a year so i don't make things worse from road wear.


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## raspantienator (Nov 20, 2007)

Wow .....lug nuts-who knew? Its good to have anal friends!


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## GTO JUDGE (May 14, 2005)

raspantienator said:


> Wow .....lug nuts-who knew? Its good to have *anal friends!*


I ain't touching that one!


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## GTO JUDGE (May 14, 2005)

LordAnarchy said:


> All the tires are the same but they were put on by a run of the mill tire place and i had the front and back aligned with one of those laser systems. I will try the 70/100 steps, check my weights and look into the roadfroce balancing. To be honest i had never heard of that before. But how do i check the balance on the *drive shaft*? can they do that at a frame shop or is this something i can do at home? Also are the front ends on these cars prone to have problems of any kind? I know, i have a lot of questions sorry. just worried. been only driving it 5k a year so i don't make things worse from road wear.


The drive shaft has to be balanced. With the car elevated and while on the throttle you can inspect the driveshaft for any kind of wobble is it rotates. It could be the wobble is so slight its not detectable by eye so having it removed and verified for balance would ensure this. Unless the car was in an accident or something happened to the undercarriage, the drive shaft out of balance would be remote. You may find little pieces of steel tack welded onto the drive shaft. Those would be the counter weights. If you don't see any evidence of little weights but see a shadow or outline of something that was there but isn't could indicate a missing weight. 

When I installed driveshafts on Mack Trucks it didn't take much to knock them off, not so say this set up is like those but don't over look it.

Is the yoke sloppy loose? Straps that hold the driveshaft tight? With used cars ya just don't know what the car went through before you got it. Eliminating one aspect at a time is a tedious process but eventually you ought to come across the reason for the shimmy. 

I would focus on the possibility of an out of round tire. You stated the tie rods and all were replaced, work outward from there.


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## Reno'sGoat (Dec 10, 2004)

If your wheels are aftermarket then you may need hub rings. Does the shimmy go away after 60 ? My car did the 60 mph shake and then would go away above that. Added some billet hub rings and the shimmy is gone.


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## LordAnarchy (Jul 3, 2009)

Reno'sGoat said:


> If your wheels are aftermarket then you may need hub rings. Does the shimmy go away after 60 ? My car did the 60 mph shake and then would go away above that. Added some billet hub rings and the shimmy is gone.


My wheels are the stock 17" but the shimmy does go away around 65-70.


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## jpalamar (Jul 22, 2008)

Make sure your wheels are balanced, lugs are torqued correctly (too many shops to use the gun), and driveshaft.

Its weird that this open happens at certain speeds. I bet when you get your rear replaced, the problem goes away.


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## LordAnarchy (Jul 3, 2009)

*Update*

I hope the rear end swap solves my prob as well. I took the car in and had all the wheels balanced and rotated at my normal shop. Couldn't find a place that did road force balancing or would have gone there. I bought a package for allignment a while back so had them check that again to.They said everything was good and put her back together. Something cahnged though, it seemed to have gotton worse. Now she shimmy's when breaking. Only seems to happen when I break from 60mph-0mph. I wasn't pushing thier limits either just normal breaking. I am confused? So it happens while driving at 60mph and breaking from it. Put new rotors and pads on the front about 1.5 years ago. They only have about 5k miles on them. IDK man. Don't own a torque wrench but when I install new Differntial will use my dad's to check/tighten all lugs step by step. Will also have driveshaft checked since the rear is going to be out of the car. Figuerd best time as any she'll already be torn apart. 

p.s. the new differntial is real pretty. got it in on the 7th. can't wait to see the difference the 3.91's with the spool will make to my 1/4 mile times!


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## GTOJer (Oct 20, 2006)

I am guessing you don't plan on driving on the street anymore and track only so this shimmy, if it only occurs at 60, shouldn't be an issue since you will blast right past that on the track.

I had this same issue and did everything you have done. It was a bad tire. If you have other GTO buds in your area, take a Sat and swap all of his tires onto your car and see if the problem remains.

Oh, and always torque your wheels yourself no matter what the shop uses. This is one of those hyper pet peeves of mine. Go to Harbor Freight and get yourself a torque wrench.


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## LordAnarchy (Jul 3, 2009)

GTOJer said:


> I am guessing you don't plan on driving on the street anymore and track only so this shimmy, if it only occurs at 60, shouldn't be an issue since you will blast right past that on the track.
> 
> I had this same issue and did everything you have done. It was a bad tire. If you have other GTO buds in your area, take a Sat and swap all of his tires onto your car and see if the problem remains.
> 
> Oh, and always torque your wheels yourself no matter what the shop uses. This is one of those hyper pet peeves of mine. Go to Harbor Freight and get yourself a torque wrench.


Acctually she is my dd. I know 3.91's much less a spool is not the preferred street set up but I only drive 6 miles ( each way) to work and it is mostly at 60mph in a stait line so I always feel it. No GTO buddies here yet or a wheel swap would be a good way to see if it is a rim or tire. About the torque wrench...honestly, just been lazy and have been putting it off. I know i need one for EVERYTHING just has not been #1 on my to do list. Will get one soon. Harbor Freight always has decent deals on stuff. I plan on having it all done by the end of the month so I will post what becomes of the shimmy after i have put her back together. I hope its not a tire either i replaced the fronts in FEB of 08.


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## GTOJer (Oct 20, 2006)

3.91s are GREAT for the street. Makes the car so much more fun and easy to drive. Also helps your mpg. Mine went up 2. Yes, up, as in better gas mileage. One of the best mods I did.

A spool on the street? No way. Your rear tires will get chewed right up. And a spool in the rain? Hope you have your deductible saved. 

Oh, and how about list all your mods so we know what to hit you up for afterwards.


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## LordAnarchy (Jul 3, 2009)

GTOJer said:


> 3.91s are GREAT for the street. Makes the car so much more fun and easy to drive. Also helps your mpg. Mine went up 2. Yes, up, as in better gas mileage. One of the best mods I did.
> 
> A spool on the street? No way. Your rear tires will get chewed right up. And a spool in the rain? Hope you have your deductible saved.
> 
> Oh, and how about list all your mods so we know what to hit you up for afterwards.


The only real mod is the rear. :lol: everyone should have the k&n filter already. If I can keep me foot off the pedal in the corners i should be ok with tires. the t/c will help too.


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## GTOJer (Oct 20, 2006)

ok, I am not explaining this spool very well. The entire purpose of a differential, posi or open is to allow the wheels to turn at different rates. When you turn your inner wheel spins or turns over less times than the outer wheel.

I worked up a small example for you. Assume you are making a u-turn out of your lane across the next lane, ending up in the 3rd lane over. My assumptions are the lanes are 9' across, your tires are 4' apart (I know, but just go with the example), and your tires are 25" tall. So in that u-turn your outer tire will turn over 13 times (12.96) and your inner will turn 11. (11.04). That is a car with a differential will do that. Your tires will turn exactly the same. So the one with the least traction will skip, hop, or slide. Your daily driver will eat tires. I will bet a set each year, if that. T/C has nothing to do with it. As a matter of fact, even if it were on, it will see each tire turning the same and will be happy.

Add to that the increased wear and stress on the 1/2 shafts.

They make a diff spring upgrade kit but that only bandaids the problem. Best thing is a Kazz but it is expensive.

I do know a little about our rearends. I am on Difftechnics list of prefered installers.


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## GTOJer (Oct 20, 2006)

ok, so the 3.91s and spool are in now?


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