I'm planning to have my 2006 FXDB front wheel rebuilt using the stock hub and a stock rear rim which is 17 x 4.5. This is so that I can fit a nice fat front tire I'm planning to use the Fatboy tire which I believe is 140/75x17. I've already fitted Fatbob trees so there's plenary of room between the fork sliders.

There seem to be a few views on doing this, mostly along the lines of either, the manufacturers don't recommend it so don't do it, or, don't worry about it it'll be fine.

Has anybody done this or something similar? What are the downsides to fitting a tire onto a rim that's slightly wider than recommended?

Thanks in advance.