I have an 08 c2s with about 4K miles on it not and recently I took a short road trip alone which is unlike the other trips I have taken in the past.

I noticed at highway speeds (such as above 70 mph) I could see and feel the passenger seat (especially at the top of the backrest) shake a little bit. I am wondering if this is normel as these cars have very stiff suspension & were never meant to ride like a luxury sedan. I presume the low profle tires could also tend to add to the sensation just a little too.

I am wondering if the tires need to be balanced better although I'd think they would have come from the factory in very good balance. I looked in the wheels and see all the wheel weights are there & in intact on both planes, that is both at the inside & near the outer part of the wheels too.

I have reservations letting the dealer start messing with rebalancing the tires as sometimes their equipment may not necessarily be as good or as correctly calibrated as what at the factory uses when mounting tires.

Ther tires are Pirelli P Zeros with 19" wheels.

Have others here experienced this too, or should I go see the dealer?

 

Sounds normal

If the vibration increases in frquency with speed then suspect balance.

Note that Porsche recommends lower pressure in your tires for lightly loaded cars - the TPMS allows you to select the load and the pressures are in the manual.

For your car they are:
Front Low load/High Load 33/36
Rear Low load/High Load 39/44

It does ride hard - but that is the point!

 

It largley depends on the roads, but if your tires are out of balance you should be able to see it in the steering wheel. while driving take your hands off and if its shaking from side to side a bit you should have the tires re-balanced.

 

If you are concerned, I'd take it to the dealer. I've read on Tire Rack that some Pirelli purchasers find them noisy and that they wear out quickly (especially the rears). A re-balancing may help and isn't too expensive. Any dealer or tire shop can balance them just as well as the factory did, and they could have worn out of balance in 4000 miles.

 

Did some cars come with P zero's and others with the PS2's? I thought my car was going to be delivered with Pirelli's, but was pleasantly surprised when I saw the Michelin PS2's; I was going to take off the zero's from the factory and buy some Pilot's, but didn't have too. My 996 had Pirelli Zero's... to me, at speed, they felt like they belonged on a covered wagon.

To be honest, my new 4S feels exactly the same at 130 as it does at 30, very smooth

 

19" wheels w/ 30 or 35 tires are going to pick up a lot of road chatter. Sure you can soften the ride by running lower inflated tires but you'll give up performance and tire wear.

So. Cal. fwys have become pretty ****ty roadways thanks to our mis-guided elected officials. I can clearly tell the difference between asphalt and concrete road surfaces. This is especially true if the concrete has been anti-hydroplanned (ie. grooved) for water run off.

You might bring your car into a 'reputable' tire or alignment shop (in my area it would Johnson Wheel Alignment or Globe tire) and have them check our your balance and possibly alignment. I think I'd stay away from your dealer for this type of work. They would most likely would sub it out to a tire shop anyway.

ps. For loooooong comfortable rides take a nice cushy Lexus. PCars (IMHO) are best for short to medium spirited motoring. If you're canyon driving or autocrossing you'll never notice the harshness or vibrations. You'll be too busy 'driving'.

 

If the wheel shakes, it's the front tires.
The seats shaking means it's the rears.
Double check the cold tire pressure and rebalance if necessary.
Good luck with your dealer.
Mine SUCKS !!!

 

i had that problem is my 2007 S550 Mercedes. But my steering wheel had a shake to it also. The front passenger seat would always vibrate, the headrest even more so. They blanced the tires and rims, replaced tires and rims,changed the motor mounts, changed the drive shaft, changed the front rotors. But the car still vibrated in the seat of my pants and the passenger seat. Fianally on service they changed the fron and rear rotors and voila, the shake was gone. I drove the damn car for 45Km and hated almost every mnute of it. I just sold the car last week.

 

Mines does the same thing.....perfectly normal

 

mine shakes as well.
I just thought it was normal.
perhaps I should have my tires and rotors looked at.

dduncan, I cant believe they did all that for you. Was it covered under warranty or on your dime?

 

A Carrera will never be Lexus-smooth.

That said, steering and suspension in these cars is extremely sensitive, which is a great thing in that it creates the "feel" we all so value. The downside is that it means that your alignment is super-important. Get an alignment every 4 months (or sooner if you're on pot-holed roads); you'll appreciate the ride.

As for Pirelli P-Zero Rosso's, I would throw them away. I recommend Michelin PS2's. The PS2's are sooth, grippy, and balanced.

 

My view is that if it doesn't feel normal to you, then it may not be. Most of us have driven and owned enough cars to know/feel what is normal and/or acceptable to us. These are cars are well into six figures, so if something doesn't feel right, instead of talking ourselves out of there being a problem, my view is take it to the dealer, even get a second opinion if necessary, but have the pros either correct the issue or tell you it's definitely normal. No point driving/owning this type of car for an extended period wondering/wrestling with various issues. It should make you feel good, not uncertain, etc. Just my 0.02....

 

hell I say go to the dealer and test drive the same model and tell them you want to see if it has the same problem. Assumig you bought the car there I doubt they'd really have an issue. Then you can see for yourself if something is wrong.

 

Sorry to deviate a bit but is there any one here to tell me if I will see a noticeable difference changing from 18" to 19" rims pls?

 

I mean a difference in stiffness of course