I'm wondering what the correct backspacing would be for a 15x7 wheel?
I've seen people fit 15x7 under the stock body work and I'm hoping I can get by without rolling the fenders.
Thanks once again!
Edit: It might help to include what type of car it is. 79 mgb
Keep the same offset as the stock MGB wheel (22mm)
The real issue is the width of the axle that you are using (if non-std MGB) and if using the std B axle then you have to cope with the documented issue of axle bias to the left side of the vehicle (about 3/8'). Given a perfectly centred MG width axle and 22mm offset wheels you should be able to use a 215 width tire with no interference.
Just as a bit of history on my conversion (Panasport 15x7 w/ 22mm offset, 225/50-15 tires, Ford axle made to MGB width, and with spring mounts welded 3/16" offset (to compensate for the afforementioned axle bias), With this combination, I still had to remove most of the flange on both wheel archs and also provided additional clearance by a subtle rework to the contour of the fender and by slightly flattening the right side bump stop. In retrospect, I should have gone a little further with the spring mount weld location as the left outer tire still rubs but not the right tire.