Thoughts on potential causes of a vibration problem...

[ZBB]

I started to notice a vibration problem with my E39 about a month ago.

Its noticeable at speed - I start to feel it at ~65mph, and between 70 and 80 mph its gets a bit stronger than at 65, but about the same in between 70 and 80. It also tends to come and go -- I'll notice the vibration for a minute or so, then it subsides for a bit before coming back again. I feel the vibration in my butt (my wife has noticed it also), and can see the dash shaking. There are no rattles whatsoever though.

It first appeared about the same time I had a slow leak in one of the rear tires -- and I suspected a wheel was out of balance. The slow leak required a new tire -- and since the tread depth on the rest of the tires was fine, I only had one tire replaced and have the spare and the new tire so I had new rubber on both sides of the rear (the older rear tire that was not replaced is now the spare). Both tires at the rear have been balanced, but the vibration is still there.

So I'm suspecting its something with the front now -- either an out of balance wheel or an alignment issue (although the car tracks true with no pulling to either side).

I've scheduled a service appointment... but wanted to see if anybody else had any theories on the issue :dunno:

[ff]

Tire out of round?

[BahnBaum]

Wheel weight fell off?

Alex

[Rob]

Sounds like balance. There are a lot of things that can cause it. From personal experience, tires have gone out of balance, snow and ice, weights falling off, once I even had brake dust pile up in one clump inside the wheel that balance was noticeably affected (that's what started my habit of taking the wheels off to clean the insides every so often).


I have about 8000 miles on my current set of tires and they badly need a new rebalance. That's what happens when you go inexpensive, I guess. The pilot sports never went out.

[SteveM]

Having worked at a tire shop, I can say that nothing due to misalignment will cause a vibration. Vibrations almost always have the following sources:
-tire balance
-tire out of round
-worn shocks
-worn suspension components
-wheel problem
-warped rotors (usually only felt when braking)

[Doug]

Having worked at a tire shop, I can say that nothing due to misalignment will cause a vibration. Vibrations almost always have the following sources:
-tire balance
-tire out of round
-worn shocks
-worn suspension components
-wheel problem
-warped rotors (usually only felt when braking)

:+1

[clyde]

Having worked at a tire shop, I can say that nothing due to misalignment will cause a vibration. Vibrations almost always have the following sources:
-tire balance
-tire out of round
-worn shocks
-worn suspension components
-wheel problem
-warped rotors (usually only felt when braking)
Add worn, loose, misadjusted, or broken steering components.

[Nick M3]

IIRC, the E39 has issues with the thrust arm bushings.

[SteveM]

Oh I forgot another potential source - worn U-joints.

[ZBB]

Well, I took the car in last Thurs, and the vibration is now fixed.

Turns out it was a wheel/tire out of balance. Interestingly it was the NEW tire that was out of balance. So I've got a new theory as to what happened:
1) Old tire hit by something in sidewall; not bad enough to cause an immediate flat tire, but it did develop a slow leak.
2) Old tire developed out of balance during slow leak. I first noticed the vibration the same time I noticed the tire was low...
3) Old tire replaced. New tire not properly balanced.

The out of balance must have been approx the same -- the vibration issues were nearly identical on both tires. I'm a little pissed at the tire shop for not properly balancing the new tire...

Oh well, at least its solved...