Strange it only affected you at 30 mph ? All other speeds okay I presume ? When I bought my first Dominator it had a stupid home made coffin side car on a double adult Busmar chassis. I rode the barsteward home and felt a right twat, probably looked like one as well wrestling with the monstrosity. Immediately took it off, chopped the coffin up and sold the chassis which was the longest drawn out sale for £60 in the history of Yorkshire wheeling and dealing. Ive never ridden a three wheeler since.
I'll go for a calendar, trouble is my Triumph is showroom fresh, and my trusty 1964 model ain't a Triumph! Will enjoy looking at your bikes though