Hi,
not sure I completely understand how wheel specs work. Would someone tell me if the following spec will fit CS without spacers, and if I can fit 18' OEM tires on those rims as well?

Size: 18x8 front/ 18x10 REAR

Offset: +48mm front/ +60MM REAR

Pattern 5x130 (that I know will fit)


thanks!

The last question first OEM tires will fit those rims no problems.

You will need spacers for the rear tires, about 12, or 13mm. The front look ok.

You can go to this site and download the tire size comparator for free. this will give you a nice freebe and a visual tool. You can also check tires yourself.
CAT Freeware -- Tire Size Comparator

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They won't properly fit a CS. With OE tires (which will fit the fronts just as they do on the OE rims), the front tires will stick out 14mm farther because the offset is 14mm less than on the OE rims. Thus, in cornering the tires may rub at the fender lip. If so, more negative camber might prevent the rubbing. Spacers would only make it worse. The rears can be made to fit with the right spacers because the offsets are greater than on the OE rims. The 265 wide OE tires will fit on a 10" rim, but you might want 275s instead. But if you worked all through that, you'd have a bit more stick in the rear, with the same stick in the front, thus adding a bit more understeer. You may not notice this change unless you corner hard. Rims that are 8.5" front and 10" rear would work better, even with the OE tire sizes. Apparently Porsche thinks the 8 and 10" front to rear stagger works better on 911s, while the 8.5 and 10" rims work better on the CS. In short, one may get those specs to work out okay with rear spacers, but they may not work as well as the OE setup, and certainly not as well as 8.5 and 10" rims with the proper offsets.

Thanks guys! This helps!!

Gents, can I pick your brain again? Same question - following sizes:

18" x 8" / 50mm offset in the front

rears are 18" x 10" - 65mm offset

(it's porsche's older sport design wheels)

Really appreciate your expertise and help in this matter!

Hello thePurist,

I believe you really need to establish your final outer rim edge position relative to your OEM wheels for an accurate understanding of what your selected wheels/tires will look like on your car, what spacers to use and if there will be adequate clearance from your fenders and struts.

The best way to do this is to go to the Porsche Tequipment catalog and record the widths and offset values of your stock wheels. Then enter this data into the wheel offset calculator (available without download) at: Wheel Offset Calculator , next, enter the width and offset info of your proposed wheels into the calculator; it will give you a comparison of the old and new wheels relative to fender and strut clearance.

Now you'll also want to compare the mounted dimension of your old tires to the mounted dimensions of your new tires. This is important to understand how much larger the new tires are compared the the old tires because any growth in this dimension needs to be considered when you calculate fender and strut clearance. This is usually best accomplished by going to the tire manufacturer's web site. There they will almost always provide tire specifications (mounted dimensions). This is the most accurate way because the same sized tire will vary slightly between manufacturers. Alternately, you can go to: Tire Size Calculator - tire & wheel plus sizing where you can compare generic dimensions of tire sizes (mounted). This calculator is also available without download. I hope this helps you better visualize the finished product buy eliminating guesswork and rough estimates!

Regards,
Joe

Well, the fronts will stick out only 12mm farther than stock instead of 14mm as on the first fronts you asked about (the OE CS 18" fronts have 57mm offset), and the rear will need an even wider spacer than the first rear you asked about.

I know you didn't ask, but my advice is to stick with the OE wheels rather than try to make wheels designed for the 911 fit the CS. I know the proper alternative (8.5 and 10" width forged wheels with proper offsets) is more expensive, but it's the only alternative I'd consider.

I'm beginning to appreciate the humor in your name, "thePurist."

... Thank you Jim. Thanks for directions, and opinion.

Actually I meant for my name to be more ironic than humorous, but I'm glad you like it