Lifted need tires
 

I just put a RC 2.5" Suspension lift on my 2000 Blazer LT 2WD. I am in the process of putting a 2" body lift on it. What size tires can I run with stock 15" wheels and a total of 4.5" lift?

These are the tire sizes I have come up with:

235/70 R15 ..... 27.95 in ..... stock

2.5" Suspension Lift
30x9.50 R15 .... 29.99 in ..... 2.04in higher

31x10.50 R15 ... 30.98 in ..... 3.03in higher
32x11.50 R15 ... 32.01 in ..... 4.06in higher
33x10.50 R15 ... 33.08 in ..... 5.13in higher

The 31's should fit fine but you'll have to get new wheels with less backspacing or you'll rub the frame.

can you recommend a good backspacing for some 15's

Somewhere around 2". You could also get 2" spacers but those are unsafe to a lot of people.