750-17 is stock size on the F3; although I cut the centers out of the widow makers and had them welded into one piece outer rings. The new rings are 17-7, a little larger than the original 17-5.5; I went with 5.5in backspacing and maybe could have gone with 5.25 but it's hard to say as that would push it away from the hub more... drag link clearance is tight, here's the wheel all the way over, right turns are not a problem...

 

Thats a close fit but man those are some good looking tires