Ok here's the deal just bought a 96 Sierra Sl single cab a month ago, decided to do a Djm 6" drop flip kit in the rear and bought 2" Djm drop spindles and 2" drop springs. Long story short not being aware of not being able to run the stock 15s I dropped it proceeded to drive off realizing the rims were hitting the lower control arms. I did some research and realized i needed to go 17s or bigger to clear. So I hopped on craigslist found a set of Chrome 18x8.5 Irocs like new for $300 with used tires. I threw them on my truck realized right away I had issues the tire was out passed the fender lip. The tires are 255/55/r18 and the backspace is 4 5/8 which I now figured out I need atleast 5" back spacing if I'm understanding it right. I take it I'm stuck now just wanted to be sure if I went with say a 225/45/r18 nothing will clear correct? Should i just sell the rims get another set with the proper backspace?