I believe that you're supposed to measure from the center of the wheel to the edge of the fender. My t-bars are at stock setting, and I have 22". When you crank your bars, you're also supposed to get different set (longer/extended) of shocks and bump stops, I think this is what you need:
http://www.trailduty.com/product_inf...roducts_id=765
Someone please corrects me if I'm wrong.