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YOUR RESEARCHTyre sizes.....again! sorry!!!!!
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Run on 285/30/18 rears
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Suggestion · Original poster
My C4 has always run on 285/30/18 rears on the Sports Design split rims that I have.
Leading evidence: 'Run on 285/30/18 rears' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Run on 285/30/18 rears' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Hi all, just about to get new rears and need some decent advice. My C4 has always run on 285/30/18 rears on the Sports Design split rims that I have. Had Michelin PS2's to start which blew out on me at 17k miles (luckily stationary).
So next went to Bridgestone S02's which I have been totally fine with. Rears have done 13k and due to a bit of uneven wear (need a geo) now need replacing. If it wasn't for the uneven wear I think I would have got to 17-18k out of these so pretty happy.
Looking around on here and various links, I see that 265/35/18 should also fit and will be more reasonable and with a lot more choice. Is this right? Anyone else with Sports Design on 265's? Compared to my SatNav my speedo seems to be about 4.5mph too much so going to 265's could actually bring this closer to the correct speed according to the tyre bible site. Doing my head in searching for answers so can you help!
How wide are your wheels? 10inch? And your fronts? 7.5 or 8? Wearing 225/40?
(Remeber the ACTUAL contact-patch of a tyre, be it 265 or 285, will be 'forced' by the wheel width, so the real difference won't even be as much as 20mm.)
The only thing that would bother me would be the chance of affecting the balance in the C4 by making the rears slightly narrower.
I mean I don't know if more width at the front vs the rear will give you more understeer in the wet? :dont know: Dunno how these all-wheel-drive Porsches behave
Handling wise, the C4 is just totally sure footed, quite hard to get it to step out, put it this way, I get scared a lot quicker than the car does!
Looking at the Sports Design wheels it's difficult to measure the actual size, they're certainly 10" as that's what's stamped on them but really measure nearly 11" where the tyre bead sits so perhaps 285's are the best.
I have 265 on 10J wheels; there is no problem there.
Do you have understeer in the wet? If you don't push the car to the limit I can't see ANY reason not to fit a tyre that is within the correct range for the wheel width, and was one of the tyres originally specified by Porshce?
Was it OE for the C4? It'll be specified in your drivers manual.
Hi Steve
Generally as a rule early 996 wears 265/35, same as 986 Boxster on 9" rim. Facelift 996 MY02> usually wear 285/30. Not sure why this, but you may find the 265 better and of course lots cheaper!
This follows the 993 where on the same size rim the narrow cars have 265 and widebodies have 285.
Let me know if u want help with tyres, will be interesting to see how the wheels are doing.
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