Quote:
Originally Posted by heretolearn
Currently building out my first Porsche 911 ever. Very new to this journey and wanting to soak in as much knowledge as possible and there are a ton of gaps to fill.
I've dug around this forum and have read a lot of posts but figured it would be the most helpful for me to ask my questions directly to you all.
I am building out a 1971 911 with my own touches to it. My rear flares are 1-1.5inches wider than SC flares and I'm worried the Fuchs I have, 15x7s, may be a bit too small. Wanted to pick the brains of the experts here and ask about the following:
1. Are 15x7 all around going to be okay with the flares that I have?
2. Should I explore going slightly bigger in the rear, say 8s or 9s?
3. If I do explore going bigger in the rear, how will that affect the handling of the car? What are some other things I need to put into consideration?
4. What kind of effect do spacers have?
5. If I explore a wider rear tire size, would that be an alternative route?
6. What am I not thinking about that I should consider?
Thank you all for your input! 
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As noted what did you do in front?
You want a balanced wheel and tire setup, generally the rear wheels & tires will want to be 1 -2" greater than the fronts w/ roughly equal tire ODs, specifics of the drivetrain and use would nail that down better.
if staying w/ Fuchs you will need very large spacers
For fuchs no mater whether 15 or 16 you are very limited
all 7s are ET23.3 with a wheel front space of 2.93", the tire will usually add a bit to that f/s
all 911 8s are ET10.6, w/ a wheel f/s of 3.93"
all 944 8s are ET23.3 w/ a wheel f/s of 3.43"
all current 9s are ET15 w/ a wheel f/s of 4.22"
a stock SC/Carrera can fit up to a 9.5 ET19 w/ a wheel front space of 4.35", but w/ a 275/40 x 17 tire runs into issues mostly on the backspace but also a a bit on the front, a 255/40 x17 doesn't have this issue
so if you have fender lips sat 1" greater than an SC/Carrera you want 1" spacer w/ a 9.5ET19 or around a 1.42" spacer w/ a 7 ET23.3
there were some early 9ET3 and 11 ET -27 x15 wheels that are scarce and extremely expensive
for these
9 ET3 has a wheel f/s of 4.73"
11 ET -27 has a wheel f/s of 6.91"
tire availability also enters this ,
if it were my car w/ a pretty decent motor and reasonable gearing I'd want maybe 9 & 10 either 15 or 17 because the tire choices are better, in 17 245/40 on 9 and 275/35 on 10 would be close to ideal
in 15
235/45 on 8.5 or 9 and 285/40 on 10 or 10.5