Stephan Schöling wrote: > It took over 1 hour to read that ;-) > > May i try to summarize with easy words, please correct me if i'm wrong. > > The frame itself isn't stable, the frontpart flops sideway (by gravity). > The self-centering effect works against that, is making the bike stable. > If I put some weight to the seat (gravity too), i increase the > self-centering effect. > My python frame (without rider) balances at ca. 8 kg on the Seat. > (Borderline between the two effects) That depends on how exactly the borderline would be defined. At 8kgs, there must be a turning angle at which the front part still flops. For a useful definition of that borderline I see to possibilites: * for a certain turning angle (e.g. 20 degrees), there is a balance * or for any turning angle the wheel flop is smaller then the self centering effect. But it is a lot of work to come up with the correct numbers I guess. I wonder if there is a simulation tool that would be able to calculate this things. > The riders weight increases the self-centering effect. > The pivot angle decrease: increase wheel flop, increase self centering > (up to a point). (we still have to find the proportion) > neg trail increase: probably not much influence on wheel flop, > increase self centering. > > Luggage placed near the rear wheel doesn't have much effect to the > stability of the bike, because its away from the SBB. > > Dirk: > You wrote, your formulas are wrong ? > What is wrong with them ? Qualitatively they are ok. But quantitative not. The real seat rise is larger then the one calculated. This can be noticed readily. The reason AFAIK is that in the models I simplified the tires by being infinitely thin, and this does have a significant effect. Dirk ============================================================ This is the Python Mailinglist //www.freelists.org/list/python Listmaster: Jürgen Mages jmages@xxxxxx To unsubscribe send an empty mail to python-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field. ============================================================