Y'know, now that I think on it, I have had several trailers w/no springs, and one was a trailer that I put all my camping gear in and towed it for thousands of miles behind several different vehicles, and it towed very well. 'Course, if I put some gear in it, it towed much better. But I have owned about 30 or 40 trailers over my lifetime, and whether they had springs or not, they ALL jerked to some degree when presented w/a large bump or pot hole. I haven't ever towed a trailer behind a bike, however! So I can imagine that anything towed behind a 2wheeled bike would affect the bike much more than it would a car or truck. Right now, in fact, I own five trailers, so if anybody needs one,..........
Mark, AKA the gingerbreadman