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Join Date: Dec 2001
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Groovie Ghoulie: What's the aspect ratio of the 225?
Porsche Gal: I believe your rear tires are 315/35/17 not 315/40

Looking at the Toyo r888: the 225/45 are 25" tall, the 235/40 are 24.6" tall, 245/40/17 are 24.7" tall, and the 255/40 are 25.1" tall. By going to a 1" wider wheel typically lowers the dia. by 1/2".
Somewhere the tire manufactures state what rim width they are using to come with the tire diameter.

You may be rubbing if your using a stock 911 backspacing of 4 7/8". On our '75 Carrera RS race car I ran 944 8x16 Fuchs with a back spacing of 5.5" and 255 tires with no rubbing issues. I use to build my own 3 pc wheels. I always used 5.5 back spacing on the 8" or 9" x 17's on the front with no issues. Also use to run 235/35/17's on the slant nose to clear the headlight buckets.
If you want even more room you can use a 912 front hub which is 1/2" narrower than a 911. But you will need to add spacers to clear the shock.
'79 930/DP935
'68 VW Turbo Crewcab
Old 06-29-2014, 11:59 AM
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