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Discussion Starter · #1 ·
900S with new tires. Steering wheel shakes rough between 60-70mph. Someone already said wheels are unbalanced. Any suggestions? ? Thanks
 

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Depends on whether it started AFTER the new tires. If not tire balance, then bent rims can cause it even if the tires are balanced.

Old tires may have worn in so you could not tell, and new tires make it more noticable. I had a total of four bent rims over the years. One time I replaced a set of tires because of uneven wear. Vibration appeared after the new tires went on. Wheels with the tires did balance ok. When we took the tires off, and put just the rims on the balance machine, you could tell they were bent.
 

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How many miles on the car? It is possible that the shaking is caused by worn CV joints. The vibration will subside when not accelerating if this is the cause.
 

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Discussion Starter · #4 ·
Just got the car about two weeks ago. It has 82k miles on it. The tires are pretty new, but the rims have alot of curb rash from the previous owner. CV Joints or Unbalanced Tires?
 

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This seems to be a case of classic unbalanced tires/wheels - this task must be done very carefully, the old bubble balance does not work very well..Even if the very best of equipment is misused, there will be wheel vibrations...

Worn CVs ?? This I doubt.

At one time - long ago - front drive used a version of a "double U joint" - this, now antique design, had to be properly set-up to avoid out of phase vibrations...and when either dry or worn out, I can imagine there were shakes and shimmies....
 

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Don't forget the possibilty of rear alignment issues?;oops:

If you have an S, you have steel wheels, right? Easier to deal with if unbalanced, right?
 

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I vote wheel balance...

And on the subject of misuse of equipment. I had a big one in this very area. Bought 4 new tires for the wifes car last fall from a reputable tire dealer. The very next day, major shimmy at 53-55 mph. I went back and here is what happened. The tires were put on the balancer and run, then weights applied. Here is the problem: once the weights were applied the guy doing the work did not run them again to verify. The dealer was honest about the mistake, said newly trained guy did it and I got some freebees :cheesy:
 

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Discussion Starter · #8 ·
Got a Front Balance. Still shaking. Thanks to Good Old Town Fair Tire, Im now missing two fron center caps. Any other suggestions? Thanks
 

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If the tires were in need of balancing, you'll notice the vibration starting around 50-60 mph and then it would disappear again around 70-80. Make sure you're test driving on a smooth road.

I would rule out CV joint since any vibration from that would be stronger and nosier when making turns at low speed.

There are tires which can't be balanced because of manufacturing defect. One example is when the tire isn't round but oval in shape, or when it has developed a flat stop. Better tire shops have balancing machine which puts road pressure on the tire and then measures balance. They should be able spot this type of problems.

If the problem is caused by wheel alignment problem, you'll notice it more through the steering and it shouldn't be speed sensitive.

One other thing is to retorque all the lug nuts (bolts actually). I have found Saabs are more sensitive to this than other vehicles. Loosen all the bolts and tighten to about 100 ft-lbs using a torque wrench in a star pattern. BTW, I never let mechanics rotate my tires because I have a hell of time loosening the bolts afterwards. I'm sure they go at it with the air impact gun so that it's WAY beyond 100 fl-lbs.
 

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Beg to differ on alignment but my rear alignment problem is speed sensitive and also I can pretty much feel it everywhere! But I seem to be one of a few suffering it.
 

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bkrell said:
Beg to differ on alignment but my rear alignment problem is speed sensitive and also I can pretty much feel it everywhere! But I seem to be one of a few suffering it.
No, the rest of us are just quietly waiting to find out how you fixed yours... :cheesy:

"Curb rash from previous owner" might mean someone who hits curbs often, so I would still vote for bent rims.
 

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If I can get to my wife's uncle's tire place...:x We were going to visit last week but were all sick w/ a cold! Doesn't look good for this weekend either but I may just sneak over to tirerack...That's not as good though b/c even though the Kuhmos are already cheap at $53, the uncle was going to give them to me for $30.


I was looking at my rear right wheel and I don't know if things have gotten worse or if I've just been smoking too much crack but it's pretty obvious to me now that it has some severe toe-in going on.
 

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I have a set of snow tires on steel rims that are useful for these types of tests. I can put on the snows in the front and compare the vibration level to the OEM alloy rims. The steel rims are less likely to be bent and out of balance.
Don't forget about the other suspension components. Raise the car and move the wheel laterally and vertically. There should be no free play. Check that the tie rod ends, ball joints and subframe bolts are not loose.
My suggestion about the CV joints was to just add another possibility to the checklist. It's also real easy to check by getting under the car and moving the axel laterally. The turbo SE models have this more than the non-turbo because of the higher horsepower.
 

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bkrell said:
...I was looking at my rear right wheel and I don't know if things have gotten worse or if I've just been smoking too much crack but it's pretty obvious to me now that it has some severe toe-in going on.
On my car, the odd wear on the rear tire went away with new rims on that side and new tires all around. The vibration seemed to go away for a while, and now is back.

Having said that, jquinn's problem sounds more like in the front end, whatever it may be.

As for me, in for a penny, in for... considering a set of new/(used) hub assemblies from a 9-3 chassis being parted. That would give me new hubs, new hand brakes, and new calipers in one shot, and the larger rear rotors the car should have had in the first place... Still leaves the crappy brake cable though.
 
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