The somewhat unique rectangular tube frame design of the Ultra Duo makes it hard for mounting a kickstand. This clamp-on kickstand has a rectangular clamp but it is about 20% bigger that the frame so the kickstand will move when raising or lowering it. I tried installing some rubber material between the clamp faces and the frame tube to allow for a stronger clamping action without marring the paint but the free play is still there. I think the Ultra Duo would be better served by a clamp-on kickstand that has a two point attachment (if one exists to fit this frame) to both of the rear fork frame tubes. The clamp-on kickstand does eliminate the interference with the pedals, always a problem with a center frame kickstand. The clamp-on kickstand is sturdy and functional, perhaps some 3D printed Biktrix specific spacers could be manufactured to improve the fit.