I just purchased a 2012 Panamera turbo that only has 14k miles. It's got 22" CEC wheels with Pirelli P Zero Nero all season tires. So far it's ridden pretty smooth, until I get on the Interstate. At around 70 mph it gets a pretty bad shake in not only the steering wheel, but also the seat. I just went to Porshce and got the wheels balanced, which I thought would make a difference, however coming back on the interstate, the vibrating was just as bad. I assume this isn't a normal issue, so what could be going on? It's almost undrivable at speeds over 60.

 

What cimes to my mind:

1. bad balancing job
2. Weights thrown off due to sticking on dirty surface
3. Bad lower control arms
4. Bad tie rods
5. Bad alignment
6. Tires worn uneven due to bad suspension components, etc

Assuming rotors an pads are greag shape.
if car really has only 14k mi on it, there should not be anything on there in bad shape.
when you say vibrating, is it a pulsing motion like something is binding on wheel rotation? Is it a wobbling vibration? When did you first notice it?

 

most likely in the aftermarket wheels with 14K on car...
If Porsche did a road force balance they should have found wheel issue so I d
look into mounting hardware (proper bolts, hubcentric rings it hopefully doesn t have).
If you have another set of wheels put them on.

 

No accidents on the car? Even suspected?

 

The vibrations are definitely more of a wobbling vibration. I noticed it the first time I got on the Interstate. I assume for now it's the wheels and tires that need to be changed. Hopefully that's all that is wrong because the vibration is unbearable.

 

Nope the car is free of accidents

 

I boughta '12 P4 and could not get rid of a shake like you describe with 20" Pirelli snowtires. I think my tire had a broken belt and no balancing could get rid of the shake. See if Pirelli will cover it under warranty.

 

Sounds like bad balancing job for sure.

 

A Hunter Road Force balance will tell you all the things like that to determine a tire or wheel issue. Pretty simple.

 

Could be a bent or out of round wheel as well

 

Could be bad balancing (try get them balanced again and see how much weights they have to put on)

Buckled rim /s

Maybe your wheels need hub locating rings. Maybe measure the hub of the rims, and make sure?