Ludwig a safety step plate covering the gap between frames does seem a good idea as does utilizing a narrower tire on wider rim for the steering tire. I've also expanded my inquiry of the effects of damping for the outrigger leaning wheel as well, giving a certain amount of resistance at that swivel point. Springing and damping the chair wheel also deserves a bit of thought as the hardtail Simplex could really benefit from a reduction in unsprung weight. The next item of concern on my list of considerations is the ability of the Sunlite forks to handle it's part of carrying an additional 250 lb. load. The tires on the Simplex are designed to handle the weight of three people on a pedicab but the outrigger wheel would need to also be a 26" to utilize the same Vee NOLA tire or go to a small diameter motorcycle size on the outrigger wheel and tire. I bring these considerations up in order to not only find answers, but also illustrate that adding a sidecar poses several design considerations. I may go the easier fabrication route and go simple rigid frame, unsprung, but still using good sidecar balance and alignment in it's design. I could also go all in with a fully sprung and completely articualted design or somewhere in between and either way be satisfied with my choice...if I do my part and build to the best of my ability the design I select. Rick C.