i have a 2005 997S and i've been experiencing steering wheel vibrations at different sped:
4-50 in city
69, 74, 79, 81, 89 at highway speeds.
I had this vibration when my tires needed changing and also right when i got new tires that were balanced twice.

the vibration is felt with my hand on the wheel and is visible if i take my hands off. the car runs true and doesn't pull when braking.


in the meantime i took my car to a PCA autoX and of course got a few sidewall rippling as is common when tracking a car. myc ar has about 500 miles on the new tires PSs

so now my dealer claims that the vibration is due to "cupping due to tracking" even though i specifically told them that i had this vibration before.
they inspected the suspension adn didn't find anything

they said they out new'ish' non-tracked wheels on the frintsand noticed a decrease in vibration.

i wasn't rally happy with this diagnosis and they've agreed to re-road test the car with my current tires and then switch out to brand new 4 tires and reroad test.

If it turns out that the tires are the culprit they're going to charge me to shop rate for diagnosis and of course not charge me if the vibrations are still there.

is there anythign else i need to have them lok at while they do this?

anyone else experience this?

 

Had the same steering wheel vibration after changing rims/tires. Car drove perfect when I bought it, put the new rims/tires on, got the BAD vibration at 55 mph+. So I was lucky in that I knew it had something to do with the new tires. In your case, I can't say for sure that it is, but the symptoms sure fit.

Do you know the machine that your tires were balanced with? A balancing with a Hunter GSP9700 fixed my vibration issues completely. Here is their web site where you can find a shop near you that has one: http://www.gsp9700.com/ Make sure to ask the tech and he will be able to tell you exactly how far off they are from perfect balance before he readjusts them.

 

Ive been having the same problem with my g35 coupe. I found out that one of the rims wasnt running true. Once I replaced that one rim, it was great again. Good luck with this.

 

it's the tires/rims.
I have a set of new OEM porsche wheels with new tires painted black. The place that painted the wheels did a road force balancing. Car vibrated. Took it again to that place. car vibrated. Took it to my local hi-end wheel place (they sell HRE, dymags, etc) road force balancing. car vibrated.
Got fed up with how lame they were... took it to porsche dealership. They charged me $90 for balancing all 4 tires. The best money ever spent. car is solid. no more vibration.

 

hmmm. thanks guys. we'll see tomorrow. i'll post what happens...

 

Try this as well - don't laugh or knock it until you give it a go. I too had this issue after swapping wheels/tires on my C2S and my dealer and I tried every single fix without luck (Hunter balance, lug studs vs wheel bolts, etc).

Due to the hubcentric nature of the wheels, it's very easy to to deflect them out a little when lowering the car down on the ground for your final torque. By a little, I min a mil or two at the hub ring is all it takes.

Start with either front wheel - with it in the air, remove it, rotate it one bolt rotation forward (picture the 5 bolt pattern, and rotate the mating sequence towards the front of the car one bolt forward). This step is unnecessary but easy to try as well (wheels are not always perfectly true, even when balanced, nor are hubs - you have 5 options, if you will, to index the wheel to the hub and you can try this or actually check hub run out if you have the proper tool to index the heaviest spot).

With the front still in the air, remount the wheel and install all 5 lug bolts. Cross snug the bolts in your star pattern, starting at the top. Gradually snug each down a few turns at a time like you normally would until they are just making contact and "snuggung up"

Here's the key - before dropping the car down for the final torque with the suspension loaded - have someone sit in the car, pump up the brake and hold it. Now tighten your wheel bolts in your star pattern with the brakes holding the rotor in place (your brakes will hold it for the required 96 ftlbs, just be sure to EASE up to 96 ft lbs bit by bit). Note - do not have them start the car - just pump up the brakes without the key in the ignition. It dawned on me that some people may do that which could be bad for the fellow doing the wheel work.

Gently lower the car, and recheck torque specs once the suspension is loaded again.

We tried everything (my dealer and I) - even went so far as to install lug studs to convert it to a lug centric setup, trying to rule out a slightly off hub on the aftermarket wheels. Nothing worked, and they used a Hunter to balance and sidewall index everything. Still, nothing worked.

Torquing everything while in the air eliminates any slight deflection you may get from dropping the car down without the wheel bolts fully torqued. Doing this eliminated the steering shimmy I had after installing new wheels.

Give it a shot - takes 10 minutes to do both sides and won't cost you a dime.

 

^^ Interesting

 

UPDATE

Drove car with tech with my tires. He confirmed shimmy at various speeds

Mounted new(ish) new tires from tire place and re-drove car with tech next day- still shimmy

Tech said he looked whole suspension over and didn't notice anything amiss. Noted and fixed loose rear sway bar (!!!!)

Tech said it's "Possible" rotors are slightly imbalanced which coudl casue vibration at high speeds but also noted my car didn't have any braking problems

so, i drove out of there without much relief from Porsche but free of charge since they did confirm i still had a slight vibration with swapped tires.

I took the carrera over to tire place to have them put my tires back ion. they said they'd do a balance with tires on for me for $80 for fronts so i had them do it.

I spoke to tech and to Nexus-6's point i had them make sure to torque everything up while the car was in teh air. They sadi they did a roadforce balalnce.

Conclusion:

Car is slightly better than before but definitely not back to 100%

Thanks for everyone's input!

 

i have the same problem im going to try and get them balanced with a high speed test first to see.

 

Make sure they use the roadforce type where it's balanced while on the car after they they remount the tires to make sure they're set in properly. Good luck

 

I had the same issue when I bought a set of P2's from TireRack. First insall had a vibration. Took it to another shop and had road force balance, with no resoution. Took it to the dealer and they fixed it with thier road force balance.

I think some of these tires are just not that balanceda from the manufacturer and most of these shops are not all that skilled at road force balancing them.

Hope you get it fixed. Had a similar issue with my A5, but that was a control arm issue, and is well known.

Good luck.

 

Didn't you just pick up your C2?

 

At any time did any of the techs check the steering rack?

 

yes,steering checked.