Hi Jürgen,
testrides are succesfull. No side forces any more, offhands riding is easy and i asked a neighbour to ride on it, he managed it in a few minutes.
Very good news from you!
So the stability criteria is a short B value. Somehow this reminds me of a picture once Olaf sent us. Could this be mathematically explained?
Attachment:
3pivots.gif
Description: GIF image