[motomanjack112]

Hello Fellow 968 forum members.



I am in need of some technical help.



I am looking at a set of OEM Porsche Turbo Twist wheels on ebay. They were on a '99 C4 and I want to see if they will fit on my '93 968 cab without clearance issues.



The front is a 7.5 x 18 Part # 993.362.134.06 The old owner had 225x40x18 tires on these front rims.



The rear is a 10 x 18 Part # 993.164.140.04 Owner had 265x35x18 Tires on these rear rims.



Any help you may offer is greatly appreciated.





Jack

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[Anchorman]

You haven't provided the most critical piece of "fitment" information - and that's the offset of the wheels. If you get, and tell us, that, you'll get the correct guidance.

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[Dave]

Jack - The offset is usually stamped right on the wheel on Porsche OEM units. There will be two numbers on either side of the valve stem. One is the width in inches (7.5), the other is the offset in mm (ex. 55).



May even show in the pictures. That is what Anchorman is asking for. It's a critical dimension in assessing fit as he notes.

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[bob blackwell]

If it is not stamped on the outside of the wheel, it will be stamped on the inside of one of the spokes. Should look something like: ET 65. Good luck, Bob Blackwell.

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[motomanjack112]

Thanks Gents,



I have emailed the seller asking if he can provide me with the offset so I can forward them on to you.



He did mention that these wheels were off a 1999 996 but that still doesn't tell us the offset. He states that the wheels are OEM, so he shouldn't have too much trouble finding this information.



Thanks again,





Jack

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[motomanjack112]

[quote name='Dave' post='34409' date='Apr 20 2007, 07:19 AM']Jack - The offset is usually stamped right on the wheel on Porsche OEM units. There will be two numbers on either side of the valve stem. One is the width in inches (7.5), the other is the offset in mm (ex. 55).



May even show in the pictures. That is what Anchorman is asking for. It's a critical dimension in assessing fit as he notes.[/quote]



The seller just emailed me back and stated that the offsets are 50 Front and 65 Rear. Will I have any clearance issues with these wheels?



Thank you,





Jack



[quote name='Anchorman' post='34370' date='Apr 19 2007, 02:13 PM']You haven't provided the most critical piece of "fitment" information - and that's the offset of the wheels. If you get, and tell us, that, you'll get the correct guidance.[/quote]



Anchor, the offsets are 50 Front and 65 Rear. Do you know if these wheels will fit my 968 without any clearance issues.



Thank you for your time.





Jack

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[Anchorman]

Irrespective of whether or not you have clearance issues (and I'll address that next), it's my personal opinion that these wheels may not look well on your car. Here's some information. On my car I have 18" wheels - 8" wide in front and 10" wide in back. The front are 57 offset, the rear are 58. Since your looking at 7-1/2" width in front, the 50 offset probably would be fine. Here's the math - the 1/2" narrower wheel means the the outer surface of the wheel would by 1/4" further in from the fender. The 7 smaller offset means the outer surface of the wheel would be 7mm (about 1/3") closer to the fender - about a wash. The rear is a very different story. Since the wheel you're considering is the same width as mine, but 7mm greater offset, that would move the outer edge of the wheel that much (again, about 1/3") inside the fender. For my taste, the 58 is already a little further inside the fender than I'd like. My previous rear wheels had a 47 offset and (IMHO) looked great - the outer edge of the wheel pretty much lined up with the fender. However, there was a little bit of fender interference, which is one of the reasons I went to the size I now have.



So - I don't think you'll have any clearance issues, I think the fronts would be just fine, but for my taste the rears would bring the tires too far "inboard". One added point - I'm not sure that I'd want a 2-1/2" difference between front and rear wheel widths on a 968 - I believe that differential is much more appropriate for a 911 where tire sizes are being used to introduce a little relative understeer to counter the massive oversteer that's inherent in the car's design. My previous 18" wheels were 8-1/2" wide in front, and there are some owners that have gone even closer to equal widths front and rear. The 968 inherently is pretty well balanced, and with the 2-1/2" width differential, you could be introducing understeer that you might not like. That would depend, in part, on how you drive the car. For example, if you drive aggressively or participate in autox or DE, that could be a very important consideration.



I hope this helps you make a decision.

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[Dave]

+1 for everthing Anchorman said.



Spot on.

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[porsche]

Jack,



You may want to consider my RUF wheels.



They are very close in size front to back (e.g., 8.5" and 9.5")



Check em out on eBay: Item number: 110115012823



   



Porsche

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[Anchorman]

These wheels certainly address some of the issues I've pointed out, and would give a very unique look. Here's where personal taste (and pocket) start weighing in.

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[Ryan]

You can use those wheels and add small spacers to offset the wrong offset.

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[Anchorman]

Good point - spacers can help in this situation (although, as a matter of principle and good mechanics, I try to avoid them). Obviously, though, they can't change the relative size of the front and rear wheels.

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