confused on backspacing

69_340_GTS said
Where did I say he should run more than 4.75" b/s on the front? I said 4.50" b/s with any diameter wheel. How is that "not accurate whatsoever"? On a stock Dart (which one could have only assumed he had based on the OP info) that much b/s will normally cause the tires to hit the frame rails at full lock. Trying to make it simple for the guy... He did not originally mention any suspension modifications, nor did he mention any desire to run
anything larger than a 17" wheel. Now that you have a lot more info on the OP's car, now I'm "not accurate whatsoever" because I posted way before you had all this additional information? Give me a frickin' break!

Yes I blew it on the offsets. Should be +12.7mm. My math sucks when I'm tired.

You didn't say he should run more than 4.75" of backspace on the front. Which is exactly why your information isn't accurate. With a 17" wheel you can run more than 4.75" of backspace, and you SHOULD.

You can run 17x8's, with perfectly stock suspension, with a 5.25" backspace and 245/45/17's and not hit anything. Not the frame, not the fender, nothing. You can't run that much backspace with a 14 or 15" rim because your rim will hit the UCA. So, when you said this

69_340_GTS said
Does not matter if the wheels are 14", 15", or 17", because wheel diameter has no bearing on backspacing at all

your information was in fact inaccurate. The OP's first post said he wanted to run 17's, which will let you run as much as 5.6" of backspace, even with the stock suspension. You can't do that with a 14 or a 15" rim.