jonathank2000

I read over the archives. Well, I thought brand new rims and tires would eliminate the vibration and harsh shaking of the steering wheel after 50+mph but it's gotten a bit worse with the new setup. It felt like a bent rim but now I know it's not. Would changing suspension to the Bilstein HD/H&R along with alignment help? Or any thoughts on possible problems with bushings on the a-arm? I don't think it's warped rotors since it happens when I'm not braking as well.

Thanks for you help!

PramTT

Jonathan:

How did you know that it is not your tire/wheel?

I had slight vibration wheel on my 993tt awhile ago after replacing both front tires. Thought it was due to just balancing problem. Got the wheel/tires rebalanced twice but problem persisted. Shop showed me somekind of low spot on the tires and got a brand new replacement from Tirerack under warranty. However after installing the new tire, vibration problem was still there.

Finally took to Wheel Enhancement and after trying several things, got to try different front wheel and voila, vibration gone! At that time the Hunter GSP9700 (wheel balancing machine) was not available so that visual inspection of the wheel does not show the problem. My problem was that wheel/tire was showing perfect balance on the wheel balancing machine.

The currently available Hunter 9700 will be able to do a "roadforce" measurement to see any "out of roundness". It will then follow by checking if the out of roundness is due to the tire or the wheel.

Conclusion: the first shop which install the new front tires bent the wheel ever so slightly to cause the vibration/shaking.

My suggestion is before you go to changing the suspension components, bring your car to a GOOD tire installer with the Hunter 9700 to check whether the vibration is due to the tire and/or wheel.

HTH,

KB993

jonathank2000,

After having my new wheels and tires mounted, I also experienced a vibration. The wheels were rebalanced and the problem was solved.

ceboyd

a warped rotor can cause problems too but it is unlikely to be the reason in this case

Ray Calvo

In my prob. 300K miles in various 911's, such a vibration was always caused by a tire/wheel being out of balance. Change tire shops.

I assume this is NOT while braking, but during highway/interstate driving. if it's during braking, the rotors are likely warped.

Terry Adams

Agree with PramTT, especially about the Hunter. I went through vibration hell with 3 different shops before I found one with a Hunter GSP9700. Problem solved. I have had a bent wheel on 3 occasions, and the Hunter GSP9700 has found each one.

jonathank2000

Thank you everyone for the info!! I didn't know about the Hunter wheel balancing machine. The shop said they used the Corghi machine. But the problem existed prior to the new wheels so I'm leaning towards alignment. I already have the new Bilstein HD/H&R Springs which I was going to install next week so we'll see if this helps. If not, I'll go back to get it re-balance.. process of elimination I guess.

Thanks for the posts!!

adsc4s

Jonathan, you will need an alignment with the new springs/shocks anyways but I doubt it will solve your problem. As Ray mentioned, it is the tire/wheel combo that is most likely the vibrations culprit. Find someone with a Hunter. I believe Al Reed in Anaheim has one. Good luck.

jonathank2000

I just came back from the shop getting my car aligned after the Bilstein HD and H&R Springs install, and believe it or not, vibration is gone!

jonathank2000

The steering wheel does feel lighter though.. and I am still going to get it re-balanced next week. Thank you all for your input!!!