Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
I always used to fit a 4.10 19 inch TT100 front and 4.10 18 inch TT100 rear to my 500's.This combination was recommended to me when I bought my first 500 by the supplying Honda dealer in 1972 and, although I've owned a few of them since, there has never been a reason to change it.