so here is the deal i have made up my mind that i would like to run a 15x7 +20 steal wheels. i have itr 5 lug 5x114.3 witch is 5x4.5 ford jeep, they measure inches not mm for backspacing, here is my question when measuring wheel offset on a 15x7 the outside of the wheel would be 15x8 becasue of the outside lip the tire is mounted on is not measured, so would a 15x7 have a 0 offest at 3.5in back spacing or would it be 0 offset at 4in backspacing? i fould these wheels im gonna buy http://www.4x4groupbuy.com/store/bla...5-p-10477.html and want to get close to +20 offset of 3/4 in off center, please help if you can and yes i have searched and found a lot of different answers btw 1in = 25.4mm

 

Kind of cut and dry, not sure how you were getting lots of mixed answers.

First off. Backspace DOES NOT equal offset.

With that said, read up on this page, and maybe it can explain it to you http://www.flushstance.com/wheel-measurements/

Offset is really an irrelevant term when it is not combined with the width of the wheel. Backspace is a much better measurement when determining wheel fitment, as it a fundamental measurement that you build off of, and work your way out towards the fender.

Also, feel free to use this backspace/offset conversion

http://www.flushstance.com/backspacingoffset-converter/