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      12-11-2012, 11:56 PM   #10
asus389
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Drives: 06 E90 325i
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Location: Michigan

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2006 BMW 325i  [0.00]
Quote:
Originally Posted by FCobra94 View Post
You said the tires/wheels were balanced and road forced, but what were the road force numbers (in lbs for each corner)?
Good question. I have tried many times to get clarity on the balance issue.

The rears are below 10 and have remained so. The roller has been on the fronts 3 times. When I first got them, one tire was replaced because it was at 24lbs. The numbers with the new tire installed were then under 10. After several thousand miles and continuing vibration, I took them in a again (to a different tire shop) and a printout showed the front tires were both in the mid teens. So can RF numbers increase with tire wear? Can the tire pressure effect the RF reading?

On the 4th attempt to balance I took it to a place that does on car balancing. They balanced the front tires first on a machine, then installed them on the front hubs. They balanced out fine on the machine, but then when put on the car they vibrated the whole car at high speeds. The left tire/wheel much worse than the right. We put the left tire/wheel on the right side to see if the worst of the vibration would follow. It seemed to. Though they were both pretty bad.

Then they balanced them on the car and they were able to effect *both* the braking shimmy and the driving shimmy. They didn't get it to go away completely, however.

It was during this process when I noticed that re-indexing the front wheels/tires on the hub changed the shimmy. Move it one lug next, vibration much worse, next lug, less. All without changing weights.

Not sure how the legit "put the wheel on the car, spin it up and see how much the door shakes" and then put weights on by hand method is. But it sure is amazing to watch.

Bizzare, right?

Last edited by asus389; 12-12-2012 at 12:01 AM.
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