GAGMAN

I am considering replacing my 15" phonedials on my '87/944na with a set of 16" 928s4 wheels (Part nos 928-362-115 and 928-362-117). In researching the specs, I have found that the 8Jx16 rears match my current wheels backspacing(6.06") and offset (2.09"), but the 7Jx16 fronts show the correct backspacing (6.06") but a different offset (2.56")! (This info from 928 FAQ) How can this be? I thought the two measurements were dependent on each other? I just need to know if they will fit my 944, and how large a tire can I get under the fender. The stock tires liste for these wheels are 225/50/16 front and 245/45/16 rear. HELP!

Adrian

Your 944 has the same front and rear offsets of 52.3mm.
Have you considered a set of 964 Design 90 wheels for your 944. They are 6JX16 front and 8JX16 rear. They bolt straight on.
225s on the front is a lot of tyre to haul around on a NA 944 by the way. I have no idea on an 1987 944 if they fit but they do not without modification on a 1985.5 with 23.3mm offset all round,
Ciao,
Adrian

Danno

Yes, they are interdependent. The difference comes in because the front wheels are 7" wide versus the rear's 8". By keeping the backspacing the SAME, you have to increase the offset. If you had kept the same offset in the 7" front, you would only have a 5.5" backspacing. That's because you would be removing 1/2" evenly from the inside and outside, thus keeping the offset the same.

It's easier to visualize this if you draw pictures. I've got diagrams and procedures on wheel measurements on my website at:

http://members.rennlist.org/951_racerx