Dale Gribble

Been having a problem with my 996 with what seems to be a vibration in the wheel...just as it would if the wheel was out of balance. Things i've tried so far to fix it:

1) new rims/new tires so there's no issue there
2) balanced by a good shop whose properly balanced my tires before
3) new alignment from Autowerks

there's still a vibration in the wheel at about 125...then worst at 140....gets better around 150 but is still there.

Any other ideas as to what could be causing it? I'm going to have the front wheels remounted/rebalanced just to make sure they were properly balanced the 1st time.

Oh..car is a 996 C2

1999Porsche911

Did you watch them balance the tire/wheels? Did they remove them from the balancer and turn them 180 degrees and recheck? Most shops DO NOT double check the balance by turning the wheel assembly. All is takes is a 1/4 of an ounce difference to cause vibration.

IF, before you installed the new wheels and tires there was no vibration, I wouldn't consider anything else until balancing and tire runout have been corrected.

ArneeA

Maybe they put counter-balances on the wheels also.

AndyK

You're talking KPH, not MPH, right??

Has to be the balance weights are slightly off. Fine for normal speeds, but off when you go very fast?

I would try to take it to another tire shop that has road force balancing, and see if they can tell if it's off.

wlee69

I have a new appreciation of "balancing" this week after I went to a place with one of those hunter GPS9700 machines with a guy who knew what he was doing. He spent about 2 hrs balancing the wheels (remounted tire/wheels to match high/low spots - did the 180 flip around balance thing) etc. I didn't think the car could be as smooth as it is right now...and I always thought the old tires were balanced....its incredible what they can do when they have the right machine and the right knowledgable person...... I'm with the 1999Porsche911 - go to a different place to get the balance done (preferably with the hunter machine).

ScottArizona

just in case, are you running spacers? I found that the 7mm h & r spacers introduced a vibration on my car, whereas the larger spacers (14 mm) were fine.

BlackCab996

I have aftermarket 19" rims on my S500. I had a slight vibration at high speeds, likely due to buying aftermarket rims. Traditional balancing eliminated most but not all of the vibration above 95 mph. I finally ponied up the money to have them balanced on a Hunter machine and I now have no problems. If I were you, I would try that as well. If you go to the company's website, they have links to shops near you who use the machine. Good luck!

MJBird993

I had a similar problem with my E39 BMW, it was a bear keeping the tires balanced properly so that the car was happy. I concur with the other folks - try another shop with good equipment and a proper technician. If that doesn't work, the wheels, even if new and of high quality, may be out of round. As may be the tires. You may consider having them shaved.

ArneeA

Go on hunter's website and look for the shops that use their 9700 machine w/ the road force balancing.

Tippy

If it is properly balanced it sounds like the tire is simply out of round, needs to be shaved.

Dale Gribble

Tippy: Dont think tires are a problem, they're brand new street tires as well.

AndyK: Yes KPH, Not MPH.

Will try 2 find someone with the hunter machine in toronto.
assuming that tires and rims check out: what might some other problems be?

Tippy

Still can be out of round, it only takes thousandths of a inch to cause vibration. Ben Choi said he had a pair of Michelins that had this problem.

In my city, there is a place that shaves the tires first, then balances while the wheels/tires are on the car.

AndyK

Beileve it or not, I was having a similar problem and my mechanic found water in the tire, from compressors that weren't operating properly! The water was sloshing around causing wobble. Long shot, but....

Benjamin Choi

Good brain Tippy

Two of my PS2s were out of round with the front with bad enough hop to make any sort of balancing (roadforce included) result in welll.... vibration at hwy speeds.

i got a new set of front tires and i'm good now

capt601

rotors that need to be replaced caused a vibration in my p-car. once they were changed out, it was smooth.