# Highway Shudder



## xcmac26 (Dec 1, 2008)

Just drove down to a wedding and back, and due to traffic was forced to travel around 60 mph instead of my usual 70. There's a pretty severe harmonic shudder that occurs at that speed. It's not in the wheel though, it's the entire car.

unbalanced wheel maybe? :confused

I ran the thing up to it's top end the other night, may have thrown a balancing weight, but i don't recall seeing any on there unless they're mounted to the inside wheel surface.

any other ideas?? I'm really hoping it's not a bearing issue or worse


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## Eric Animal (Oct 28, 2007)

Check : alignment, rear control arm bushings, drive shaft including U joints, and motoer mounts/tranny mount.


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## 68greengoat (Sep 15, 2005)

If you don't feel it in your steering wheel then your front tires should be good. Could be the rears. Wouldn't hurt to balance them all again. I know alot of people like to keep their weights hidden, but the best balance you're going to get is if you let them put weights on the inner AND outter lip. Maybe ply seperation. Bearings I think you would hear if they were going bad....


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## Rukee (Feb 8, 2007)

Not sure which rims your running, but the Cragars I have to realign them from time to time. Wish I could find some eccentric rings for them.


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## Silver69GTO (May 25, 2009)

Rukee said:


> Not sure which rims your running, but the Cragars I have to realign them from time to time. Wish I could find some eccentric rings for them.


That is one of the reasons why I got rid of the Cragar SS wheels that came with my GTO. The other reason was that they were 14" wheels.
Bought a set of 15" Cragar Street Lites and never had a problem since.:cool


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## xcmac26 (Dec 1, 2008)

Thanks for the tips guys, i'll look into it first chance. Busy weekend so the car's gonna have to stay in the garage for a couple days.


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## 68greengoat (Sep 15, 2005)

Rukee said:


> The Cragars I have to realign them from time to time.





Silver69GTO said:


> That is one of the reasons why I got rid of the Cragar SS wheels that came with my GTO.


IMO, it's a small price to pay for some good looking classic wheels....


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## geeteeohguy (Feb 2, 2008)

I already posted but it's gone. Check the wheels first, sometimes the tire/rim can be matched by rotating the tire on the rim to eliminate low spots. The tire can be in balance and still have axial run-out and cause a shake. I lost a wheel twice with mags.....not Cragars, though. Had unilug Ansen's in the '70's and lost a rear wheel on the freeway on my '66....1/4 panel damage, and rear end damage. Lost another unilug wheel (no name) on the front, but it didn't come all the way off....broke a couple of wheel studs. Different car. I worked for a large tire store for 14 years as a mechanic, and over the years, saw a lot of broken studs and body damage caused by unilug "one size fits all" type wheels. Not on MY car.


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## crustysack (Oct 5, 2008)

Rukee I believe THE TIRE RACK carries all sizes of tire rings- although they don't like to sell them seperate if you dont buy wheels there you can usually talk someone into it


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## Rukee (Feb 8, 2007)

I called them before, they don't offer anything with the sizes I need.


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## jetstang (Nov 5, 2008)

What are eccentric rings, and why would you have to realign the car with Cragar SS rims more than other rims?


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## crustysack (Oct 5, 2008)

the rings fit inside the rim centering it on the hub, as for the cragers i can't answer that


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## 66tempestGT (Nov 28, 2009)

i think he means he has to loosen the lugs and make sure the wheels are centered. not an actual front end alignment.


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## Rukee (Feb 8, 2007)

66tempestGT said:


> i think he means he has to loosen the lugs and make sure the wheels are centered. not an actual front end alignment.


You are correct, sorry i could have been more clear.


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## jetstang (Nov 5, 2008)

Oh, your talking unilug rims, got it,


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## ppurfield001 (Jan 21, 2008)

xcmac26 said:


> Thanks for the tips guys, i'll look into it first chance. Busy weekend so the car's gonna have to stay in the garage for a couple days.



I had the same issue between 60 and 70 MPH. No issue below 60 MPH or above 70 MPH. No steering wheel shudder but rear view mirror was vibrating a lot between 60 and 70 MPH. Turned out I lost a balancing weight on the drive shaft. Had the shaft rebalanced and that did the trick. Good luck.


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## batmans (Aug 16, 2007)

I had the same problem and it disappeared (by coincidence) when I replaced the liquid filled radius rod bushing (I think that's what it's called) with the White Line solid Urethane bushing.

The factory bushing was leaking every where.


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## Rukee (Feb 8, 2007)

batmans said:


> I had the same problem and it disappeared (by coincidence) when I replaced the liquid filled radius rod bushing (I think that's what it's called) with the White Line solid Urethane bushing.
> 
> The factory bushing was leaking every where.


We're talking classic GTOs in this thread.


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## batmans (Aug 16, 2007)

My bad - that's what I get for looking at "new posts" not knowing that it included "everyone"

LOL


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## Rukee (Feb 8, 2007)

I just ran into a machine shop who says they can make the eccentric rings for the Cragar rims. He's suppose to stop over next week to take some measurements. I'll let you know how it goes.


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## xcmac26 (Dec 1, 2008)

just to give a little closure on this...

Car was up on the lift getting some exhaust work done, and Took a peek at the wheel I thought might be giving me problems. Turns out I threw the balancing weight when I did my little top end experiment. quick trip across the street and 9 bucks for a balance later and she's smooth as silk once again. Guess I just need to do the speed limit or close to it


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## Too Many Projects (Nov 15, 2008)

You need better balancing weights if they come off at speed......
I had a 70 Chevelle with a 155 top end and the weights never came off my wheels....


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## likethat (Oct 5, 2007)

185 no trouble yet :seeya:


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## 66tempestGT (Nov 28, 2009)

glad you found it and it was something simple.


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## 66tempestGT (Nov 28, 2009)

i would like to see a timeslip or radar verification of that 155  next you are going to toll me it was a stock 402.


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## xcmac26 (Dec 1, 2008)

likethat said:


> 185 no trouble yet :seeya:


your bike came limited to 187, typically bikes have a 9-12% speedo error. giving you the benefit of the doubt, your speed was actually 168. sorry to disappoint. 

to be fair i thought i hit 173 on my cbr1000rr only to learn the above info afterward. manufacturers build the error into the modern digital speedos for safety reasons. it's complete BS but i swear i'm not BS-ing you.


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## xcmac26 (Dec 1, 2008)

Too Many Projects said:


> You need better balancing weights if they come off at speed......
> I had a 70 Chevelle with a 155 top end and the weights never came off my wheels....



found out after the fact that the shop the wheels went to for balancing is full of asshats who don't do good work. thankfully all they did was mount the tires and weights. no leaks so i'm assuming good beads.


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## 68greengoat (Sep 15, 2005)

xcmac26 said:


> your bike came limited to 187, typically bikes have a 9-12% speedo error. giving you the benefit of the doubt, your speed was actually 168. sorry to disappoint.
> 
> to be fair i thought i hit 173 on my cbr1000rr only to learn the above info afterward. manufacturers build the error into the modern digital speedos for safety reasons. it's complete BS but i swear i'm not BS-ing you.


Use a GPS, that will give you an exact speed........


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## likethat (Oct 5, 2007)

Either way I found the limit several times. Its plenty fast on 2 wheels. Power Commander


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## likethat (Oct 5, 2007)

The power commander releases the limiter and add 15 more horse power. The top end is over 200 mph but my speedo only shows 185mph. So I only know that it was pegged out and the mile marks fly by pretty fast. I am just razzing you about the weights a bit. It is cool that it was only a wheel weight instead of something worse.


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## xcmac26 (Dec 1, 2008)

likethat said:


> The power commander releases the limiter and add 15 more horse power. The top end is over 200 mph but my speedo only shows 185mph. So I only know that it was pegged out and the mile marks fly by pretty fast. I am just razzing you about the weights a bit. It is cool that it was only a wheel weight instead of something worse.



Time for a turbo on that beast!


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## likethat (Oct 5, 2007)

It's plenty fast as is for my old butt.


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## Rukee (Feb 8, 2007)

I wouldn't mind finding a SC kit for the Harley. :cheers


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