I have a 21 on the front and a 17/50/200. The problem with the rear tire is that it will not necessarily be a stock item if your out in the wild west where distance between towns can be vast.

 

i know its not an EXACT match and i'm sure guys will wanna chime in about load ratings, blah..blah..blah...
BUT ! a 200-55-17 is the stock rear tire on a Fat Boy, so i'd think that most dealers would have it in stock, so that should be able to help keep you from being stranded if you're out on the road....
Just food for thought.....

Now that i think of it i'd be more concerned about a dealer having a 21" front tire... that might be tough...... although the new CVO Softail Breakout runs a 130-60-21 (which is new, and IMO the best option for a 21" Bagger) ..the CVO is the ONLY bike that runs this tire and we all know there aren't many of them out there so probably not a dealer stock item either....

 

18" front and rear, and be done with it.

~Joe

 

thats a good point about the rear. only problem is HD wants 3-400 dollars for one...guess if you need it in a pinch you're willing to pay

i bought two 23" front tires because they're only made by one company and i wanted one on standby