Planing on buying new rims and tires for my 72 GS. Contemplating 17x8 in front with 225/50-17 Nitto NT555G2’s for the rear 18x9.5 with 285/40-18. Going with 4” backspace on the front. Not exactly sure of the rear backspace, was thinking around 5”. Front tires are 9.17” width 25.91” diameter, rears are 11.42“ width 26.97 diameter. Want to keep the sidewalls sections even. Haven’t picked out a wheel as of yet but want to be sure of backspacing on the rear to see what’s available.