Sam996

Hi,
I have had my 03 996 cabrio for about 16 months. I just put new 18" Continentals on the car with correct Porsche sizing. I am disappointed that when I bring the car up to anything over 70 mph, the car seems to vibrate. My daily is a 16 Dodge Charger and that car is smooth at all speeds. So I would have thought a Porsche would be that much better at handling high speed. Wheels are OEM and seem to be perfect.
What do you recommend? Were they not balanced correctly? Any other possible solutions? Or is this the nature of the cabriolet?
thanks.

dgi 07

Have the wheel/tire assemblies roadforce balanced.

808Bill

No, it's not normal for any car to vibrate. Did it vibrate before?

Simonripley

Agreed. Same thing happened to me. Turns out three tires needed to be balanced. Problem solved.

Cuda911

Indeed. Something in your balance or alignment is amiss.

Volkert

So check out if can find a tireshop with a Hunter 9700. Then you need to check out if they actually know what they are doing and will spend the time to get it right. On my car I had this issue as well and had the wheels balanced twice, every time perfect. Still problems. Then I had them "roadforced" on a Hunter9700. 3 tires were bad of which 1 got solved by rotating the tire on the wheel, 1 sort of OK and 1 that could not be solved. Those last two were brand new Michelin PS2 tires. Got them replaced and then it was perfect. So even new quality tires can be bad.

Volkert

nckwrnr

This is good to know Im on my second set of wheels and tires I have had balanced twice now and get a vibrations above 70. Found a local place that does road force balancing I will have to give that a try. The vibration drives me crazy.

These cars seem very sensitive to tire balancing makes sense though since there is so much steering feedback.

AWDGuy

Flex disk guibo in good condition?

San Rensho

Check for a tire being out of round or the rim being out of round.

Byprodriver

I do not believe that was the source of the problem.

Volkert

Neither could I. But there it was....

The tires were new when I picked up the car. I drove it 2000 km with speeds up to 220km/h to ensure they were heated up correctly and had seated themselves well. They were balanced again (although at that time we thought the vibration issue was related to the rear tires).
When put on the Hunter9700 it was clear the balance was good but the tires still had issues. It could not be fixed by rotating the tire on the wheel. When we put new tires on, they balanced well and also the Hunter9700 was satisfied. When driving, finally the vibrations were gone and now the car drives like a train, very solid.

Silk

Same here with 4 brand new Bridgestone S02a. 1 out of spec and 1 on the edge of acceptable. It can happen ... I was able to swap for two others.

The hunter can measure the variance on the tire height and rim and it was definitely the tire.

I hear from the tire fitter that Pirelli are usually the most difficult brand to balance.

Atrox

agree got mine done at firestone. No need for a Porsche savy tech the hunter is idiot proof.

Volkert

Indeed, you need a tire guy, that is all. Although the Hunter is pretty idiot proof you can still screw up if you don't know what you are doing. However, I believe Hunter does leave a certificate to whom they trained when it was delivered. You can do a lot more with it then "just balancing the tire" so I believe if the guy is savy with it and you want to spent the time and maybe some extra money it can make a lot of difference to how the car drives. Especially at high speed.

himself

Do you run any type of spacer? They can cause problems as well.

-td