I don't have a spare and the one Bruce Stone thought would fit does not. I have measured the backspace on the Fuchs on the car now by turning the tire over and holding a T Square from one side of the rim to the other, by taking the measurement to the lug hole I get 103mm
When I do the identical measurement on the rim I bought as a spare, that measurement comes to 126mm, plenty of room to spare I thought. Not so when putting the spare on the car it cinches onto the calipers even with a 1/4inch spacer on the car. WHERE AM I going wrong?? Thanks for your time. Karl

Don't you have bigger brakes on that car? We need to know the details?

You neglected to consider the profile of the wheel, which is more important in clearance of the calipers than is the offset. The Cap'n

The front hast 930 turbo rotors and calipers, on the rear there are vented cross drilled brakes don't know from what year. I did not mention the rears since I thought if it fits on the front the rear would as well. There is also a 1/4' spacer to increase the distance from rotor to wheel. The wheels are stock Porsche Fuchs 7 inch in the front and 8 inch in the rear.
Don't know about the Fuchs profile, but apparently the previous owner had to shave the calipers to make the whole thing fit.

Stock Fuchs 7 what p/n?
If they are P/N 951 7x16 they have increased brake clearance.You will need a 944 turbo spare.

You are not the first to mention the 944 turbo Spare I would have to try it to make certain it fits, thanks for the suggestion. Attached are numbers from the back of the wheel on the car now. Thanks for your help. Karl

Pretty sure those are early 911 wheels with that number...

http://members.rennlist.org/911pcars/WheelWts.html

Thank you Mikez, with one link you have given me the offset, 23.3mm
and the backspace 112mm Thank you very much. Karl

With the backspace being 112mm for both front and rear wheels, but the 8" wheel in the back has only an offset of 10.6mm and the 7" front 23.3mm, will I be able to find a spare that fits on both front and back??

yes.. if you define what "spare" means to you.

Finding a modern collapsible/space saver spare is one thing.

Or, finding another 7x15 wheel, which will work front and back (since it sounds like you have flares) will also work.

The 8x15 is an inch wider "towards the outside" of the fender. It is still listed as having a 112mm backspace.

The "compromising" issue is how much trunk space you will give up for the "comfort" of having a full size, genuine old style spare. Or, you could carry a can of "fix-a-flat" like GT3s do

Thanks for all your thoughts, maybe that can of Fix-a-Flat is the simplest solution to my problem, sure have learned a lot by asking. Thanks karl

My wheels are 7 and 8"x 15's. A mini spare with the right offset I would be happy with; Boxter Spares may actually work. Will try to find one try it and let you all know. Thanks Karl

The search is over, well almost. Took the car down to the Porsche dismantlers this morning and tried to find what I needed the old fashioned way, by trying on a few spares and found that the 944 Turbo, the alloy spare fits just fine. While in the area ran across the street where they had a 17" Boxter spare that fit as well but too tall for the wheel well in the back. Now I just have to keep my eyes open for what I need and I'll be all set, thanks for all the help. Karl