996 with 19" wheels and tyre pressures

[Cpt Stirling]

Can anyone help or point me in the right direction please? I've just bought a 2001 996 C4. It has non std 19" sport design wheels with Pirelli 235/35/19s at the front and 295/35/19s at the rear. Any advice on the correct pressures would be appreciated.
Thanks

[Orangecurry]

I hope you have a typo in that post, otherwise the 4wd system is under stress beyond the design tolerance, due to the circumference difference between the axles.

[Cpt Stirling]

Sorry, yes, my mistake they are 30 profile on the rear.

[Orangecurry]

I would start with the 18" pressures, and drop them in 2psi steps until you find a setup you like.

Personally I'd bin them asap, and source some OE 18s. I would imagine that the 19 w&t package weighs significantly more than some of the OE 18s.

[Cpt Stirling]

Thanks Jonathan, yes, I do plan to change to the 18s. I see you are in W.Sussex, the car came from Chi, have you any experience of Auto Technics who have serviced it. I was thinking of continuing to us them as there is nothing similar on the Isle of Wight.

[Orangecurry]

Sorry no. I've used no-one on the south coast - nearest to you that I have used is GCS near Horsham who know what they are doing.

But for normal servicing, anyone can change oil and a filter.

[WindyM]

I have a 997.2 T4S with 19s and I run 2.3 bar at the front and 2.5 bar at the back. A good starting point? HTH.

[Cpt Stirling]

Thank you for the advice J and Windy, trial and error methinks (within reason). Incidentally I've just taken the wheels off and the fronts are wearing unevenly so I will will book it it for an alignment check. I'm over on the mainland for the Revival so have booked it in at an Indi in Chi and I'm sure they will advise as well. This Porsche thing is obsessive!