[jhein]

Originally Posted by tdavidl

...my question then is, what's the widest tire I could put in back so that the outer edge of the tire just stays inside the top edge of the fender opening and should a smaller backspace be considered?

The only way I can think of is to actually take measurements. You would need to know what your current wheel backspacing and rim width is. Then you'd have to take measurements of where your current tire is sitting in the well. Then you'd have to look at all the combinations of rim width, backspacing and tire width to see where they would all sit compared to what you have now.

My rears are sitting pretty deep in the wells, I haven't actually measured but it's at least 2-2.5". If I stayed with 4" BS then I could easily do a 275/60. That has a section width of 11", 2" wider than my 225/70. Also that tire is 28" tall so it would help fill up space if the car sits high. You may even get away with a 295/50 as far as width, but that is a 26.7" tall tire so it won't fill the well as much. Don't know for sure about clearance for a tire that wide but I think if you stay with a stock 4" BS then it shouldn't rub on anything on the inside. All of that assumes you're staying with a 15" wheel of course.