Excessive vibration

[Michael911]

I have owned a 1990 964 C2 tiptronic for 18 months, which has covered under 20k miles from new. I had a C4 before with 40k miles before yet the suspension seems harder, particularly noticeable on an uneven surface, where I feel a lot of vibration.
I have just had it serviced by Porsche Hatfield who suggested changing the tyres, which are nine years old. They said if that doesn't work it could be the wheel bearings due to lack of use, however this can go away if the car is used more. Failing that they may need to be changed.
Has anyone had a similar experience, who maybe able to help.
Thank you.

 

[iangray100]

I've had a similar issue and it was the tyre rubber had aged and they were not 100% round after the vehicle had been left standing . So the car would vibrate when first run for a few miles basically each tyre had a "rubber standing" flat spot . I changed all the tyres for the correct N rated versions ( Bridgestone in my case ) and being fresh rubber the ride was back to normal and still is 2 years later.

On lightly used cars, tyres wont were out but will age and the rubber ( its actual plastic compounds these days ) will age and go hard .

Yes 9 years is to old for car tyres , max age really these days is 7yrs +/- and then replace no matter what the tread depth . Some countries in Europe actually force you to replace tyres at the MOT due to age because of the danger of "hard rubber" . The UK has no age limit yet , only a manufactures recommendation.

I do not see it being the bearings at all, as you would get a rumble all the time and not a vibration

Make sure you replace all 4 tyres at the same time as the 964 is very tyre sensitive

 

[Michael911]

Thank you for that, much appreciated