After weighing up the merits and pitfalls of the head tube option Paul mentioned the Mosquito with it's 4 bar rear. Here I've modified it to get the riders weight more within the wide part of the area covered by joining the three contact patches of the tyres. I've also used a narrower top bar. This has the benefit of moving the riders C of G more to the outside on a corner than a long bar does. I'll need to be careful with body to wheel interfaces with this but feel I've left enough room. Because of moving the C of G further it can be narrower but only to the point of not hitting the rider with the tyres. Again I can use the rear suspension of a kids mountain bike on the front. In doing so I am requiring very little play in the pivoting parts and may have to mod the pivot of the triangle to a pair of quality rod ends if the std system proves too sloppy.
I have added an "X" at the back (the dotted white line) as a stop to prevent the pivots of the 4-bar from going over centre. This system can not be allowed to do that as it would never recover without stopping and getting off. This system will allow me about 30 degrees of lean which is more than a wide top bar will give.
I have added an "X" at the back (the dotted white line) as a stop to prevent the pivots of the 4-bar from going over centre. This system can not be allowed to do that as it would never recover without stopping and getting off. This system will allow me about 30 degrees of lean which is more than a wide top bar will give.