This is the response I recieved today from Hogpro on the 200m rear.
On the '09-'010 Baggers we normally put a 200MM tire on a 17X6.25" wheel. We don't reccommend a 200 on the 18X5.5" wheel, it can get a little squirrely on you. As far as your stock H-D Agitator Wheel, I don't know what size it is. If its a 18X5 or 18X5.5 you should probable stick with a 180MM tire.
Odd they would say this. Wonder why it "can get a little squirrely on you".
According to the Metzeler V-Twin catalog, they show their ME-880 tire in 200/50-18, with proper application to be on a 5.5" - 6.0" rim width. Yhey don't show proper fitment of that tire on a 6.25" rim. I wonder what tire Hogpro uses that shows proper fitment to be on a 6.25"? Maybe thay are referencing 16" rims, which Metzeler shows as requiring a 6.25" rim width for a 200/60-16 tire. Aslo, in a 17" rim they also reference 6.0 - 6.5" width, making 6.25" width ideal. Only in the 18" widths do they drop to 5.5-6.0". Look at the attached table, specificly items:
1307500 - (16" rim requiring 6.25" rim width for 200/60-16)
1712300 - (17" rim requiring 6.0-6.5" rim, making 6.25" width ideal)
1435100 - (180/55-18 - stock SESG size on stock Agitator rim, 5.5"-6.0")
1619600 - (200/50 -18 - a "Plus 1" upgrade to a 180/55-18 tire)
Full Metzeler catalog can be found here:
http://www.us.metzelermoto.com/en_US/browser/attachments/pdf/2008_METZELER_VTWIN_UPGRADE.pdf I've had pretty good luck with the ME-880's (although they don't wear very long) and will probably do a full swap front/rear with the 200mm on the back. Dunno when I will get to it but should be by next spring. Got other mod priorities on the table right now.