Sorry for bringing this up again, but I have been looking for over an hour now and cannot find the backspacing of the factory 17" wheels. (I can find 20" over a dozen times)
so....
2010 Ram 1500 TRX4 Reg Cab, 17" wheels
whats the backspacing?

I am asking this because I currently have 315 Falken wildpeak at's and wheel spacers, I like the stance it is at now, but the rim is too narrow for that tire and they are starting to wear poorly.

 

I had this same problem, on the inside of the wheel you will see a number and this is the backspacing. I have a 2010 st but it had alloy rims and my backspacing was 5 inches. I put on 33/12.5/ 17 but had to use aftermarket rims. The rims were the same backspacing but they were 9 inches wide so they were 17X9 with a backspacing of 5 and 0 offset and they fit perfect, no rubbing what so ever. I put on a set of general grabber red letters, the thing I don't like is that you can feel more through the gas pedal. Hope this helps.

 

Same as 3rd Gens Look HERE