Wheel/Tire Fitment Questions - Pics and Measurements Included

[zeeboost]

I've tried searching the forum as much as possible before posting this, but I'm about to drop $1500 and wheels and tires, so I'd like to see if I'm overlooking something. Plus, a lot of the posts result in people not really knowing for sure because every setup is different, so here's mine:

 

Setup - 1975 280z widebody project. I'm about to order MM coilovers, Tokico Illuminas, camber plates, rear disc conversion, 300zx front brake/rotor setup (5lug) and some other chassis mods. I currently have a 4 to 5 lug adapter (5x4.5), which also acts as a 1" spacer.

 

I'd like to fit some 315/35/17s in the rear with cobra 10.5" wheels. I'm pretty sure the fronts will be 275/40/17 mounted on a 9" rim, and I don't think I should have any rubbing issues, although if I do, I can always get a tire with a smaller cross section. With the wheels that I'm looking at, the front backspacing is 6.1", and the rear is 6.9". I work at a Ford dealership, and we had a 17x9.5" rim in stock with approx. 6.3" backspacing (I think, I lost that measurement). I mounted a 275/40/17 tire on it, bolted it to the Z, and took some measurements. Although I will be installing coilovers, I figured I'd measure the shortest distance from the tire to the spring perch. That was .425". On the other side, the shortest distance from the tire to the flare lip was around 43-44mm (1.7"). I grabbed two techs and had them push down as far as they could on the rear of the Z. She doesn't squat very much, so the tires never came too close to hitting the flares, although I'll need to do this again with the 315s. Any better suggestions on how to measure this?

 

Pics (camera phone, sorry):

 

Tire to perch (.425")

 

Larger view

 

Tire to flare (43-44mm / 1.7")

 

Rear shot of the flare/wheel

 

It looks like the flares should give me enough room for 315s

 

Side rear shot

 

If you need any other info, let me know and I'll do my best to provide it.

Summary: Will 315/35/17s fit in the rear with my setup? Rear b/s is 6.9", but I'll be using a 1" spacer with coilovers. If you have any questions, comments, or suggestions, don't hesitate. Thanks!