I'm thinking of putting a 17 Rear Rim on my Nightster and really looking at the ones off a Street Bob has they are an exact match to front just in different size. Stock is 16x3 and Street Bob is 17x4.5. I have seen several people do the 21" front which I had on my older Sportster but not the rears. Anybody done this? I think it would look great plus could fit a wider tire on it which I have already made slight provisions for including removing all wiring from fender and new slimmer mounting hardware.
I'm currently doing the same thing as well... already have the spacers, 17" wheel with the 180 tire mounted on it, and just started to take things apart today. Will post pics when I'm done.