"Most rigid" meant having both sides of each wheel supported, and any forces applied to that wheel had to be applied to both sides. Well, in those days, most bikes were chain driven, and none that I recall had chains on both sides of the rear wheel, and that meant: "Expect torsional flexing of the rear wheel to the right." I remember the Honda 1500 with a transverse-mounted 6 cylinder engine that would break loose totally on acceleration, spinning the bike on its own axis, dumping the rider at 60mph. Imagine the surprise of those poor, untrained American kids who had no concept of suspension geometry, when they got on that bike. All they knew was taking off from a red-light at full throttle, in a supposedly straight line, to get to the next red-light. Heh heh.
I also remember the BMW with the double trailing link front suspension. Interesting setup. I like suspended, spring-limited, castoring front wheels on gyros too. I also think I like 4 wheels more than 3, as well.
