Need Help On Front End Vibration

[ye12]

I have a front end vibration that starts at 50 MPH ever since I had my e30 modified 2 months ago. The vibration comes up to the steering wheel and it ranges from mild to violent.

My 1989 325i has 88,000 miles on it and has had the following modification all done by the same specialty BMW shop a couple of months ago:

1. Eibach Pro Kit springs installed
2. Koni Adjustables
3. Front control arm bushing replaced with M3 bushings
4. Racing Hart 17x7.5 wheels with hubcentrics
5. 3 different sets of tires to try to eliminate the vibration: Fusions, Faulkens, and finally Yokohama ES100 (215x40).
6. Alignment done twice
7. Wheel balancing done 3 times and the final one with a special machine that adds loading to simulate actual road reaction.
8. All suspension components checked for wear and replaced if necessary.

The specialty shop I deal with says that the wider 40 series tires does not absorb much vibration, therefore the vibration is there. But, I've had other vehicles with 40 series tires and no vibration problems. Could the 215x40 tires be stressing out the stock tie rods, rack, etc ?

Hope someone out there can help me out. I'm open to all suggestions.......... thanks

[draculia]

ball joints, wheel bearings, tie rods, rims bent, or any of the recently installed parts being installed incorrectly.

[MrM3]

i think theres a good chance its your wheels. plastic hub centering rings will never make the wheel fit as good as a hub centric wheel. i think it's worth trying to fit new ones either a size smaller, a size bigger, or just the same size if your current ones are starting to wear away.
i had aftermarket wheels for a short period and sold them because i couldnt get rid of the 50mph vibration (and a couple other reasons). i, like you, had the tires balanced multiple times, had 2 or 3 allignments done, new suspension, and still couldnt make the car feel right. When i eventually sold the wheels the new owner said he bought some new hub centering rings for them and the vibration had all but dissappeared. I didnt really care at that point because i had no plans of keeping them with or without the vibration, but I would deffinately try buying some new 57.1mm hub centering rings before you start messing with more major things like tie rods and strut mounts

[ye12]

Originally posted by MrM3@Nov 7 2004, 12:12 PM
i think theres a good chance its your wheels. plastic hub centering rings will never make the wheel fit as good as a hub centric wheel. i think it's worth trying to fit new ones either a size smaller, a size bigger, or just the same size if your current ones are starting to wear away.
i had aftermarket wheels for a short period and sold them because i couldnt get rid of the 50mph vibration (and a couple other reasons). i, like you, had the tires balanced multiple times, had 2 or 3 allignments done, new suspension, and still couldnt make the car feel right. When i eventually sold the wheels the new owner said he bought some new hub centering rings for them and the vibration had all but dissappeared. I didnt really care at that point because i had no plans of keeping them with or without the vibration, but I would deffinately try buying some new 57.1mm hub centering rings before you start messing with more major things like tie rods and strut mounts

[snapback]226278[/snapback]

Thanks for your input! I bought my wheels new a couple of months ago so the plastic centering rings should still be okay. I checked both front wheels while mounted on the car with a dial indicator last night. I only checked the axial runout on the inside of the wheel and the worst one was only 10 thousands of an inch. I did notice that both tires did have a slight low spot. I wonder how much would cause vibration.

You could be right about the problem being the wheels, because this is my 3rd set of tires on these same wheels in a couple of months (The shop did not charge me anything to change over after putting miles on the tires) and the vibration is still there. I though Racing Harts were supposed to be good quality, that why I bought them.

[ye12]

Originally posted by MrM3@Nov 7 2004, 12:12 PM
i think theres a good chance its your wheels. plastic hub centering rings will never make the wheel fit as good as a hub centric wheel. i think it's worth trying to fit new ones either a size smaller, a size bigger, or just the same size if your current ones are starting to wear away.
i had aftermarket wheels for a short period and sold them because i couldnt get rid of the 50mph vibration (and a couple other reasons). i, like you, had the tires balanced multiple times, had 2 or 3 allignments done, new suspension, and still couldnt make the car feel right. When i eventually sold the wheels the new owner said he bought some new hub centering rings for them and the vibration had all but dissappeared. I didnt really care at that point because i had no plans of keeping them with or without the vibration, but I would deffinately try buying some new 57.1mm hub centering rings before you start messing with more major things like tie rods and strut mounts

[snapback]226278[/snapback]

MrM3, Thanks for the suggestion on the plastic rings. After reading your email, I check all 4 wheels and found this:

1. Both the hubcentric spacers and the plastic rings on the front end had a sloppy fit. With a feeler guage, the plastic ring measured 12 thousands of an inch gap and the hubcentric felt about the same. The worst the wheel could be off-center would be 24 thousands of an inch plus any wheel distortion. I shimmed both up with tape.

2. The rear hubcentrics were fairly tight, but the plastic rings were as loose as the front ones. I also shimmed these up.

I tested my e30 to about 60 MPH down a back road and it seemed very smooth, without any vibration.

Thanks for your help, I think you found the problem!

[detour54]

Nice work!