[jimmy b.]

Originally Posted by Racinfan83

Another question for Ya'All. Car has a pretty bad vibration over 55mph. Feels like tires out of balance. Took it to one local Chevy dealer here a while back. They balanced tires. Still had vibration. So I took it to another Chevy dealer here last week and had em do it again. Guy said a couple of them were off by 1/2oz. SO - drove it to Chicago and back this weekend and it still shakes like crazy. It's not a harmonic vibration like a loose u-joint or driveshaft would make, and not a side-to-side shaking of the steering wheel either. It is more of an up and down vibration that feels to me like bad tire balance. Tires are Nittos with probably 90% tread - no uneven wear I can see.
Is there a "trick" or special machine required to get these big wheels balanced? I am taking it back to the second dealer (most recent) next Monday to have them redo it. I know on my little Honda daily driver with normal tires - they had to do them 3 friggin times before it was right???

Here's the part I don't understand, you had the car at two different dealers and yet neither mechanic was conscientious enough to make sure the vibration was gone before they parked the car. So what did you pay for? Seems to me they could have made more money had they put the effort into determining exactly what is wrong and making additional repairs if that what is needed. I question whether they had a real mechanic do the work or just some young kid instead who basically does oil changes and change tires. Oh and if it was a real mechanic and he probably gets paid flat rate, won't spend any more time than the job at hand pays him. I could spend a week on this "flat rate" topic alone, but that's a thread all by its self at a later time. Now I know there are a lot of great mechanics and I'm not bashing ya's but it pisses me off when some one who can actually afford to take their car to a dealer that they should have the best trained professional hopefully certified people work on their car and they end up with letting crap like this out the door. I put most of the blame mostly on management and the almighty dollar. Ok I'm done ranting but if I was the mechanic and I couldn't get the vibration out I wouldn't be able to sleep till I figured it out thats just me I'm a nut case anyway. Sorry to be so long with this. Back to the case at hand.

If the vibration is felt in the steering wheel only along with the wheels check all front suspension components including the rack assembly for wear.

If you feel the vibration in the seat of you pants check along with the wheels all the drive line, rear suspension components for wear.

A simple easy check to do is jack up each wheel separately (one at a time) just high enough to spin the tire freely and get directly behind or in front depending on front or back and just look at the tire and see if 1 if the tread is running true, 2 the bottom of the tire is running true and square and 3 if the rim and or axle is bent. If any of these wobble or don't run true while you or some one else is spinning the tire this could be part or all of your problem. Could be something as stupid as the tread or an internal belt that has separated or some damage. If there's any type of wobble you'll see it.

just remember one wheel at a time and spin tire by hand... on the rear you probably have to jack both wheels cause the posi rear won't let you spin one tire by, it self with the other on the ground. Just safeguard and block the front wheels ... hope this helps and sorry again about the long post.

jimmy