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Old 01-11-2015, 03:58 AM   #1
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Maybe wrong thread but still wondering why Porsche puts 18" originals wheels 7,5" and 9" 225 and 265 tires? I am thinking changing to 215/40 and 255/35 tires. Any downsides to this? I think possibly a bit more light feel to driving..? Car is 2004 S and with optional sport chassis

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Old 01-11-2015, 05:44 AM   #2
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Maybe wrong thread but still wondering why Porsche puts 18" originals wheels 7,5" and 9" 225 and 265 tires? I am thinking changing to 215/40 and 255/35 tires. Any downsides to this? I think possibly a bit more light feel to driving..? Car is 2004 S and with optional sport chassis

Tervetuloa,

If your car is unmodified, as in no front camber modifications, I would go toward less stagger front to rear to squelch the inherent understeer of these cars. The low cost approach would then be to get a spare set of rear wheels to fit on the front and run say a 245 or 255 front and 265 rear.

I wouldn't go with a smaller width tire than OEM at either end. With our weight, these cars can really use more tire.

I don't understand all the love for 17" wheels-

No advantage in gearing as the OD of all the 17" performance tires is right at the same as many of the 18"'s thanks to the market being brainwashed with the +1/-1 concept (there are no 17" Series 30-35 tires that I know of)

Not really any advantage on weight - you can get some very light 18" wheels (OZ's for example), and data on tire weights from at least one mfr show a 265/35-18 weighs actually 1 lb less than a 265/40-17.

Disadvantage in clearance - After I shimmed my rear trailing arms for bump-steer, the nut hit the wheel on my 17" wheels.


The only thing I use 17's for are my wet track tires where narrow tires seem to have a hydroplaning advantage.
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Old 01-11-2015, 05:30 PM   #3
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Quote:
Originally Posted by biglimited View Post
Maybe wrong thread but still wondering why Porsche puts 18" originals wheels 7,5" and 9" 225 and 265 tires? I am thinking changing to 215/40 and 255/35 tires. Any downsides to this? I think possibly a bit more light feel to driving..? Car is 2004 S and with optional sport chassis
255/35 tires are unobtanium so probably not the best plan. 225/45/17 and 255/40/17 are very common sizes available with lots of tire choices everywhere.
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Old 01-12-2015, 11:37 AM   #4
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I meant 225/40x18 to 215/40x18 front and 265/35x18 to 255/35x18 back

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