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Need help with this wheel/tire calculator

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I posted this on http://www.6speedonline.com and haven't gotten any response.


Im trying to decide on tires for my new wheel setup.

I found this great wheel and tire calculator but Im having trouble finding some of the specifications.

For instance to figure out if the tires will interfere with the suspension its asking for "suspension clearance". Its also asking for fender clearance and wheel well clearance? Dose anyone know this information?

Im getting 20" x 9.5" in the front and 20" x 10.5" in the back.
Every time I do a search for sizes the closest I come it people running 20" x 9" in the front and 20" x 10" in the back.

I wouldn't mind running all 10.5 all the way around but I don't think that will work.


2004 Cayenne S

Any help would be greatly appreciated.

Here is the wheel and tire calculator.

Edited by DRIZCOL
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It would be helpful if you tell us the exact model and year of your car.

Porsche has "approved" tire and wheel sizes (including offsets) that can be used without issues on your car.


Thank you! I have updated the original post. Its a 2004 S.

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  • 2 weeks later...

Approved (by Porsche) 20 inch wheels are:


FRONT: 9 x 20 offset 60 mm

REAR: 10 x 20 offset 55 mm




FRONT: 10 x 21 offset 50 mm

REAR: 10 x 21 offset 50 mm


If you have PCM then your PCM defaults will need to change with wheel selection.



I'm running 10.5 x 21" BBS RSII wheels with no problems, the offset is 52mm.


Thanks Guys, I appreciate you the info. Here is my situation, I bought a used set of 22" wheels with tires. The set fit but but there was a manufacture defect and after about 2 months I found that each wheel and a crack in at least one of the spokes on each wheel. Not just a hairline crack but a crack all the way through. I contacted the manufacture and they have agreed to replace all of the wheels. I asked if I could get a different size and a different model wheel because I wanted a stronger wheel and more side wall on the tires. They only offer 20 and 22 inch wheels and the widths are 8.5", 9.5" and 10.5". I want the look of 22" with the side wall of 20" since I don't think I can do that Im trying to find the best compromise and I think that option is 20" wheels and tires. Im fine with staggered widths but it would be nice if I could do 10.5" all the way around. I need to find out if thats possible, thats why I wanted specific specs for the wheel and tire calculator.

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