What's too much backspace?

[IvelDesigns]

here are my measurements:

outside of frame to outside of frame == 36"
inside of fender to inside of fender == 71"
axle from mounting surface to mounting surface == 59"
Rims == 15x12
tires == 325/50/15 (27.8" tall x 12.9" wide)

If i get a wheel that has a backspace of 7.5", basically 1" off center, is that reasonable? If i did my math right, that should leave me with 1" of space on the outside of the tires, and a good 2+" in the inside.

[Houston54]

Assuming you have no inner fender issues to worry about and leaving clearance of 1.5" on the inside of the fender on each side for rubber clearance, the BS I come up with is 7". This will provide 4" of clearance on the inside. Things not taken into account though include the sidewall bulge when mounted on the rim if any.

If you wanted to reduce the outside clearance just subtract the amount taken away from the wheel/fender dimension from the above BS dimension. If you need to increase just do the opposite.

Someone correct me if I missed something there.

[IvelDesigns]

with so much room on the inside, i'll play it safe and set it up so the wheels are in further.

i can always go the route of spacers if needed.

So is a 7" or 8" BS to much?