Well, have to admit some of this went over my head. Interesting though. TandemGeek says Santana etc are "most refined in this regard as it has very short steering trail". I was interested in his comparison about the way a Co-Motion and a Santana handle at various speeds. But on this "trail" business: let's say I want to measure the trail on my old 531 tandem. I've got a measuring tape in hand. What do I do now?