Does anyone know what size rear tire would fit on a 2004 FXST without modification to the struts, frame, etc...? I have been told a 200 should just fit.

 

200 tire won't work on your 2004...it will interfere with your final drive belt.

 

What is the biggest tire that will fit?

 

You got it on now with out relaceing with a 180 Duece rim. I have heard (no experance) that will let you run a 180 if you carefully recenter the tire. But again thats just what I heard and you know how that goes. If you go any bigger belt and inside fender support plates will rub. Not pretty. Stick with the stock tire unless changing swing arm or struts.

 

I run a 150. Any more than that and I think it looks retarded on a stock 16" rim with all the overhang.

 

So wait, if you were to change the belt to a 2006+ one, and swap out the fender and supports, you could run a 200mm tire & wheel?

 

160 will fit barely. Not really worth it because you can't slam it w/o rub. You can run a 180 w/a wider 5.5 rim but, you'll need a new fender. A 200 will fit w/ the new skinny belt and front/rear pulleys, rim, fender.