I've had a private conversation with a dealer regarding the "open" frame designs, with no lateral tubes. He points out that tandem cranks have a winching type action which causes a "bow and arrow" effect on the frame. If the remaining tubes are not designed to counteract this, then the frame will not perform as well as a laterally braced frame. His opinion is that the Paketa design "pretty well negates" that effect.

For you people riding these designs (Paketa, Calfee, Arizona, CoMo) what's your feeling on this?