Jürgen Mages wrote: > Thorsten Borm wrote: >> Until today my experience with the 20"-Python was 330 km. I always >> missed the really safety and relaxed feeling because I needed 1 meter of >> the road for myself. I was always afraid of other traffic members at >> narrow roads and speed above 20 km/h. My biggest trip was 38 km at one >> day - but I was totally broken at the end. >> Today I made a little test with the geometry of my 20"-Python. I changed >> the BB from above of the frame tube to a position below of the tube >> (-10cm) which you can see at the picture. I don't know why, but there is >> a big progress: >> Only little nervous Zig-zags, much more self centring effect, more >> safety feeling at higher speed and a better view towards the road. Now >> I'm able to drive nearly the line I want to. The position is still high >> enough to keep pedalling at narrow turns. With best regards >> Thorsten > > Interesting info. Good that you did not gave up! > > I guess that what happened to you was quite similar to my experience > with the PX.5 one year ago. I made the BB-EOS 8 cm longer to adjust > it to my length and suddenly the bike was no longer rideable for > me (before it was ok). > > The gravity center of the front part became too dominant/high and > the wheel flop effect started to overpower the self centering. > Resulting that I felt like sitting on a seesaw with the front part > moving from one side to the other. After I made the steering angle > 10 degrees steeper the bike was normal again. are you saying that on your own python the self centering is the most dominant force, more then the weight on the pedals? I just did a little test: I sat on the bike, hands on the floor keeping the bike straight up, and feet resting on the pedals. Then I tried turning the front part and see for which the turning angles I have to use force to stay at that turning angle (i.e. where the self centering is dominant). For quite a big range (I guess -15 -> +15degrees), self centering is so, that it does NOT come back to straight by its own. Rather it is "neutral": it does not tend to go further in a bend but does not tend to go straight. Only further outward I need to use force to keep a that angle. It is difficult to test this realistically this way, its difficult to shut out for sure the tonus in the legs. How heavy would a typical pair of legs be on the pedals? may be I could integrate it in my program if i had that data. the sun is starting to peep from behind the clouds again! hurray! 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. ============================================================