Vibration

[alvitdk]

A while back I noticed a lot of vibration at speeds higher than 70mph. Its not the typical steering wheel shaking, thats actually quite smooth, but the whole car is shaking, the mirrors and loose pants having a nice rhythm to it, but I'm certain it's not normal. Now, I have not hit any pot hole or curb, tires are fine, they were put new on the car when I purchased the car from the dealer 15k miles ago. Any idea besides alignment? I can't imagining anything else really. It starts at about 70 to 75 and gets worse the faster I go but I did not try to get any faster than 90mph, dont need points on my license

[LJKelley]

No the 128i should be smooth 100+ Shockingly smooth. Don't forget these cars are made for those speeds on the autobahn.

Could be alignment, suspension, wheels (just because the tires are new doesn't mean the wheels don't have damage or are inproperly fastened).

Does it drive straight without you holding the steering? Feel the lug nuts to see if any are loose. Take it back to the dealer and inform them of the problem.

[Focusedintntions]

Make sure the wheel weights from when they were balanced didn't fall off.

[alvitdk]

Thanks for the suggestions, yes steering is straight and wheel weights are all where they should be. If tires would be unbalanced I guess I would have the typical steering wheel shake, but that's not it. I will take it to the dealer next week.

Thanks

[smellthebeans]

Sounds like feathering?

http://www.procarcare.com/includes/c...dtirewear.html

Alignment should be checked yearly. But, I have mine checked with the purchase of new tires.

[Tom K.]

Originally Posted by alvitdk

Thanks for the suggestions, yes steering is straight and wheel weights are all where they should be. If tires would be unbalanced I guess I would have the typical steering wheel shake, but that's not it. I will take it to the dealer next week.

Thanks

While steering wheel shake is usually from unbalanced FRONT tires, a general shake beginning at 70 mph or so could be from an unbalanced or damaged rear wheel, but is probably NOT the result of misalignment.

I'd check rear balancing, wheel condition and suspension. If any of the tires are unevenly worn, then you should suspect alignment.

Tom

[alvitdk]

Thanks, good advise. I might just switch the rear tires to the front, technically if t hose are out of balance, I should have steering shake.

[alvitdk]

So problem is solved, I got new tires mounted, this time as a square setup, 225/45/ZR17 all around. Looking at the old front tires though, they did not show any signes of feathering as suggested, just can't figure out why that would be. Suspension feels great, I might go and have the alignment done.

[T1T2GRE]

Thread resurrection!

I just got a CPO 128i cabrio, and it had an odd front end shake at exactly 38-41 mph. Otherwise relatively smooth. The dealer had to put on new RFTs to CPO the car for me. I thought maybe there was a little break in for the new tires, but it didn't improve, so I took it in. They said all 4 were not balanced (huh! I just bought the car from you jokers...whatever) and the right rear wheel was cracked. They fixed all that and the shake is ALMOST entirely gone, but there is still a small vibration as you pass from 38-42 ish.

Any ideas? I keep thinking it's possibly an underlying suspension issue as well, but it did improve significantly s/p tire balancing and replacement of the right rear wheel.