there were several different types of sissy bar/strut combinations. have had no experience with the ones that mount from the rear, so i'm gonna leave that for somebody else. the ones that mount in a hole from the top, there were two different designs on them. the first one was the same thickness as the non-sissy bar ones and had an enlarged "goose egg" looking area around the hole (useable but not the prettiest girl at the dance). the second one was thicker and smoother the full length of the strut (the kind you want to take home to momma). both of these mount with a screw from below into the sissy bar. but to go a little farther, some of them use tapered ends on the sissy bars, with these, you have to have the matching ferrells. BUT you will always want to put the split in the ferrell to the inside next to the fender because they tended to spread and crack the strut, rendering them useless. the other type of strut/sissy bar combination has straight ends with the hole in the strut straight to match. sounds a little confusing, but i hope it helps.
