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Tyres

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YOUR RESEARCHTyres

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Suggestion
Or your car could need a GEO (suspension geometry check/adjust).
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Tyres

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Suggestion
Or your car could need a GEO (suspension geometry check/adjust).
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Tyres

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Suggestion
Or your car could need a GEO (suspension geometry check/adjust).
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Tyres

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Suggestion
Or your car could need a GEO (suspension geometry check/adjust).
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Tyres

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911uk: 1 discussions

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POST 1 / ORIGINAL POSTEROriginal post

I have recently become a Porsche 996 owner. My 996C4S will need new rear tyres soon. The owner's book that came with the car says 285x30x18 tyres should be fitted but the car is fitted with 295x30x18 tyres. Which size should I fit? Could the bigger tyres be causing the twitchyness I'm experiencing on uneven roads? All help or comments welcome.

POST 2Original post

Twitchyness could be many things - for instance P-zeros are appalling one worn down beyond half original tread-depth. Or your car could need a GEO (suspension geometry check/adjust). Re the tyres - the difference in rolling diameter in those two rear sizes is only 6mm. The 295 is actually a much better match for 225/40/18 which I imagine are on the front? so 285/30 = 628.2mm 295/30 = 634.2mm 225/40 = 637.2mm So the NORMAL answer is to fit the best tyres available in whichever size... but I don't know how precise you have to be with the Porsche AWD central viscous-coupling. No good asking an OPC, as they won't know, but would never admit that :grin: Anyone on here know for sure?

POST 3Original post

The C4S should be fitted with 295/30's at the rear. It is the C2 and C4 which have 285's on the facelift model, and 265's on the pre-facelift.

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