Guys,

Since the day I got my winter tires installed, I'm having vibration issue at high speeds. When I'm on the highway, doing 77mph, i feel a vibration on the floor of the car and slightly on the steering wheel. No matter how many times I got my tires balanced at different places, I just couldn't get over this issue. Just to see if I am correct or not on feeling the vibration, I went up to 135mph yesterday and the car was literally "shaking". What other things can cause this vibration? Who can solve this issue for me? Dealer? Tire shop? I'm ready to have this solved at any costs. I've had enough...

Could it be some kind of problem with the air suspension thingies?

Also, just curious, what happens if I do 140mph with winter tires?

 

what size are the wheels?

 

they're 19"

 

I wonder if it's drive shaft related?

 

Have you changed the wheels with the tyres or just a direct tyre swap? If you changed rims you may need a hub centering ring (had this happen with wheels that were made for multiple fitments). Otherwise if you just changed tyres, it could be a defective tyre. This sometimes wont show up on the balancer but will in real road conditions. The fact it is in the floor woudl tell me its in your rear wheels, not the front. But you may want to swap wheels around to see if it changed the vibration characterisitcis. Depending on the speed rating of the snow tyres, 141 is not outlandish. Most hihg performance snows are now V rated to about 180ish. Hope this helps.

 

Didn't you just have some (other?) wheels straighten / balanced recently? If you weren't having the problem with the other set, then it HAS to be this set tires / wheel combination related. You had this set balanced on a Hunter

http://www.gsp9700.com/pub/search/FindGSP9700.cfm

You checked for a build up of ice/snow/cinders on the inside of one or more wheels? If the tires are rotation direction sensitive that may be it. Really need to isolate the symptoms / causal relationship a bit more.

 

If it's tire related, how can I prove that do discount tire? I really don't think genuine Porsche wheels can get bent, especially 19" ones. They always had 275/40/19 tires on them, which gives enough sidewall to absorb the little potholes.

I'll try having the tires balanced again. Will the dealer solve this problem if I just bring it in and say that there's a vibration issue.

 

That was me that had my wheels straightened. 3 of the 4 wheels (22x10 Techart Formulas) were bent and no amount of balancing helped get rid of the vibration that showed up over 60mph. After they were straightened I have a wonderfully smooth ride again!

 

Any wheels can get bent; OEM or after market - if that is the cause of the vibration. I don't know if we're there yet. If it were me I'd: 1) put on a set of wheels / tires that I don't have a vibration issue with (if available), 2) talk to the technician that did the most recent balance and/or look at the paperwork to see how much weight went on which wheels (probably a good bet that the wheel(s) with the most weight have an issue), 3) switch front to rear wheels around to try to isolate if it's a bad wheel or not - you should get more or less steering wheel feedback if that is the case, 4) take the Pepper to a shop that has a Hunter (presumably a little more savvy that most [other] tire/wheel shops), 5) go to the Porsche dealer depending upon the relationship that I have with them. If the problem is NOT the wheels/tires then, depending upon mileage on your Pepper, could be steering gear slop/play, suspension, drive shaft(s), .....

 

I have 16k miles on it as of today. I went to discount tire to have my tires balanced with a road force hunter balancer, they technician said that my tires were all out of balance again. He balanced them again and problem is kind of less annoying now. I don't have any friends who has 19" wheels to see if its wheel related. I'm 700 miles away from the regular maintenance, I'll ask them to check, and they'll say that they couldn't replicate the problem bla bla... It's not a real vibration, just something that I feel on my feet. How are your steering wheels when on highway? Are they as smooth as a Mercedes-Benz car or can you feel the tires thru it?

 

With only 16K it's not ([more than] probably) suspension, steering gear box, drive shaft(s). If they can't replicate I'd be tempted to say, "Hop in, I'll show you." Stock tires? Where they rotated? Unless you "drive like you stole it" - all the time - which I doubt - wear should be relatively even on all four corners. This doesn't get better after 5 to 10 miles - does it?

I've got an 08 CS with 12K miles. I can steer the wheel with a wet piece of spaghetti.

 

It's not about softness of the steering wheel, it's about feeling the tires through it when you're on the highway with constant speed.

I drove my car as I stole it all the time, my stock set of tires are worn off already at around 11k miles and I've bought these new tires at 15k miles, in between 11k and 15k, I've had an accident due to bad tires They were so "worn off" you can't even imagine

I believe due to the tread of the winter tires, that vibration kind of thing is acceptable, or I'm just fooling myself, either way, I'm stuck with this problem for now. I'll try testing again tomorrow at higher speeds since I've had the road force balancing today, let's hope I won't get caught by the cops If I again see the obvious vibration at very high speeds, then I assume it's a drive shaft related issue and will let the dealer guys take care of it..

 

OK. Sorry - didn't know about the accident part. If the wheels have a relatively even amount of weight on them to bring them into balance (on the Hunter), then I'd be leaning toward suspension issue cause by 'accident'. PM if you'd like ... be happy to 'what if' over the phone. Steering in my car like a Benz - although I've been a Bimmer guy for past two decades. CS is my first Porsche.

 

Did you change wheels with the tires or tires only? What type of accident was the vehicle involved in?

The timeline is important. Which one is correct:

1. ACCIDENT -> summer tires without vibration -> new winter tires + same wheels -> vibration
2. summer tires without vibration -> ACCIDENT -> new winter tires + same wheels -> vibration
3. summer tires without vibration -> ACCIDENT -> new winter tires + new wheels -> vibration

If it is #1, then it is probably a simple tire and/or balance issue.
If it is #2 or 3, then it could be any combination of damaged wheels, tires, balance, driveshaft, alignment, frame, etc. Depending on the type of accident, there could be damage far beyond the wheels and/or tires.