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I currently have a set of 18" turbo twists that came off a 996 Carrera 4. They are 18 x 8 front and 18 x 10 rear. They currently have 225/40/18 fronts and 265/35/18 rears.



I found a set of OEM 2011 Cayman S wheels with tires and I am wondering if they will fit without any rubbing issues onto these wheels and on my 94.5 968.



Cayman tires are 235 40 18 front and 265 40 18 rear. Pilot Sport PS2. I will end up having to sell the wheels if I get the set.



I did have the Turbo Twists on my 95 968 cab so I know they fit with the sizes listed above. I am wondering if the extra 1" of tire in the rear is going to be an issue.



Opinions?



Thanks,

i just dealt with the rear size yesterday. it is a problem if you plan to lower the car. it's REALLY close. messes up the gear ratios too, which isn't so much of a problem supercharged, but naturally aspirated it will cost you in acceleration, albeit at the potential benefit of slightly better fuel economy.



as for the wheels themselves, you need to know the offsets. then you can use the wheel calculator

Just remember your target overall diameter is 25". A few sizes for reference:



Front -

225/40-18 = 25.08"

235/40-18 = 25.40"



Rear -

265/35-18 = 25.30"

265/40-18 = 26.35"



(these figures are straight math only - different tire brands will run slightly smaller or larger, you never know)



I'm running 225/40-18 and 285/30-18 on virtually the same spec wheels (Carrera 2 lightweights) with no rubbing. My car is lowered a bit with 1.4 degrees neg camber in the rear.

the other thing to remember is that the larger diameter screws up the corner balance big time. dealing with that now. tires are being changed.