hey all,

looking for some advice on where to direct my mechanic.

I've had a slight vibration at ~70mph for the 2+ years I've owned my 550 sport. My rims (style 124) and suspension are bone stock. Initially I thought it was a bent wheel, and then I became convinced it was the tires. Decided to take the direct route - 4 new tires and had every wheel checked. One wheel had a slight bend at the lip, and I had a reputable local shop that does all of the work for the dealership repair it. All good I would think after a hefty expense. Not so. I still have the same vibration - mostly feel it throughout the car, not so much on the steering wheel.

I can only guess I have a bad suspension part. I've done many searches on this, and I can't find a list of possible causes for this problem. Everyone's vibration seems to be a bit different. I can't be back and forth to the mechanic every week, so I'm hoping the collective expertise here will help me to get in there once, check all potential causes and find the issue.

Thanks a lot.

 

I assume you've rebalanced your wheels, several times possibly. Even if you have, get the wheels balanced in a roadforce wheel balancer.

- Antti -

 

Road force balance with smart weight turned off. Not sure that's your problem but if you already paid for the balance ask them to re-do it with the smart weight stuff off.

 

What happens when you do 75mph and you tap the brakes and hold with light pressure does the vibration go away? How many miles are on the car?

 

sorry - forgot to mention that I had roadforce balance done when the tires were installed. aligned as well. all done at the dealership less than 500 miles ago. pretty sure that isn't the problem.

regarding another question, the car is smooth as butter at 80+. I've not noticed anything when I tap the brakes above 75, but I'll try that this evening. car has about 53K miles

other thoughts? thanks for the help!

 

Had the same issue on my 535 stock wheels with new RFT's. had to get them balanced twice by dealer before it was good.

 

My '04 545i does the same thing. New tires and two wheels straightened due to pothole and it is still there. I may go the thrust rod bushing route next. At 90k+ miles it is getting time for new suspension components anyway. While under the car, I am going to look for any failed harmonic dampers, if any (My E38 has a large harmonic dampter bolted to the tail shaft of the auto tranny box). Have not owned my E60 long enough to all the components yet.

 

don't dismiss the rims just yet. I had the same problems. went through 2 sets of tires and 3 sets of rims. the 1st set of rims were 124's and were bent/cracked. so I replaced them with a new set of TSW wheels. vibration was still there. messed around with hub rings, balancing, the works. one guy said, I bet its the rims. I contacted discount tire direct who I bought the wheels from and explained the problem. they sent me 2 new rear wheels. after putting the new wheels on, problem solved, smooth as glass

 

My bet is the tension strut or wishbones. Replace the wishbones first - upper and lower in the front axle..
Good luck!

 

Thanks for the additional input, guys. Sounds like some good options to check:

1. reached out to the tech who installed the tires to see about rebalancing. I can also have him check the rims again. I continue to fear this might be the problem.

2. While there, I will have him look at the thrust rod bushing, harmonic dampers, tension strut and wishbones.


I'm mostly clueless on what the things are in item #2, but I trust my tech. I'll let you guys know what he finds.


Thanks again. This site kicks ass. I guarantee the SA would look at me blankly if I mentioned anything beyond balancing and bent rims.