Hi, Thanks for all the comments so far.. I "rode" it for two days now. the second day there was a slight improvement of my skills. (although spectators might have tought otherwise. For me it was quite a trill to witness the balance in the bike and the forward force.) Different things have to be changed. First i gonna take care so that the ergonomics improve. Need to put de BB closer to my seat. For straight lines its ok but when i want to make a corner make leg is to short. And put the seat in a more upward position. I also tested the bike with some bricks in the cargo area (under the seat.) This added weight made it steer earier. I guess its a combo of more pressure on the pivot, and lower center of gravity. The good thing was that the frame didn't have any problem with those bricks (apr 10kg) So thats the positive side of the bike weight being just under 25kg.. Patrick: I have exactly the same philosophy about my own lack of skills.. (Skills in frame building and in bike riding) I am gonna send you a personal message, I am sure it can be instructive for me.. From: patrick_van_gompel@xxxxxxxxxxx To: python@xxxxxxxxxxxxx Subject: [python] Re: introduce myself Date: Sun, 18 Sep 2011 18:06:26 +0200 Hey, I must agree with Dirk, I think the position of the the pivot point doesn't matter for wheel flop. For wheel flop you have to look for the centre of mass of the front end and the contact point of the tire. The further the centre of mass it is away from the pivot axis and the closer the contact point is to the pivot axis, the more wheel flop you will have. Hoi Gijs, nice to read your story and see your building pictures. I live only 20km South of Eindhoven, so if you need any help or wanna try my bike, just ask. I'm still a rather new pythonist myself, but the little experience I have might be usefull to you. The big question I had was: did I mess up the bike and is it unrideable, or is it me and do I need to learn how to use it. I convinced myself it was the latter ;-) Good luck with learning. Patrick Date: Sun, 18 Sep 2011 12:40:24 +0200 From: dirk.bonne@xxxxxxx To: python@xxxxxxxxxxxxx Subject: [python] Re: FW: introduce myself Hi Vi, I think this is misleading. Only trail and angle are the important design parameterswhere along that axis the pivot is positioned should not matter. From the youtube films you posted it is also these parameters you changed! As far as I can see, the height of the BB is only important related to the seat height. I find it difficult to see from the pictures of Gijs how seat-BB difference is. At first sight it doesn't look that excessive? I guess Gijs should just have a lot of patience. Everybody who learned to ride a midsteer bike knows it takes a lot of time. Dirk On 18.09.2011 01:30, Vi Vuong wrote: Hi Gijs, You may find excessive wheel flop with the BB much higher than the pivot. My first attempt was not ride-able based on this design, http://www.youtube.com/watch?v=Lmx_F8RpY2o In second attempt, I moved the pivot up to the axle level http://www.youtube.com/watch?v=JE1zgCftocc http://www.youtube.com/watch?v=ursy9LxXlqc Vi From: gijsbertusneppuc@xxxxxxx To: python@xxxxxxxxxxxxx Subject: introduce myself Date: Sat, 17 Sep 2011 22:02:07 +0200 Hello pythonists, I like to introduce myself on your "mailinglist community". Me and my homebuild bike. I discovered the python-recumbent on a late night surfing session on the internet. I immediatly got excited when i saw the full documented building steps and all the fotos of home builders. I like the lowrider style and the great variousity in looks.. And I thought by myself I (even I) could do this. I am not an engineer or welder. I have a dayjob working with psychiatric patients, and i am living together with my girlfriend and two year old daughter. My technical education is mainly LEGO technic. But i do have a welding machine and a drill and a grinder and some "boerenverstand" (=farmers-logic, Dutch for common sense..). I showed my girlfriend (the next day) the photos en videos on Utube and she saw the Pythoon of Dirk Bonne and she went: " O that is nice for our little daughter!!" Me too, I was impressed by the pythoon, first because of the looks, i love the complexness of all the little tubes. And second for the practical use of the bike. I thought, well if i gonna make one, why not a bike i really like! I hope, Dirk, if you read my mail you will think that i am inspired by the pythoon and not just a lazy copycat... ;-) In the last three weeks i completed the bike. (check: www.tinyurl.com/fietsgijs) Now i only need to do fine tuning and last jobs. Need te do brakes, fine-tune the allignement, paint, seat cover, and so on. Specs: -Pivot Angle 60 degrees (maybe change i'll it, if you have an advice on this subject, let me know!!) - 2 x 24 INCH tires - Wheelbase 160 - Weight 23 kg (oef..) - Front tubing 30 X 20 X 2mm - Seat height : 40cm The rest i need to measure Now i need to learn to ride it. I discovered that this is really really difficult. First day, I rode two meters max without stepping off.. ( And no i am not gonna put films of this attemps on utube ;-) ) I guess/ hope this is mainly a case off practice. Altough i read on many Python E- stories that a little change on the pivot angle can make a great difference in the ride-ability of the bike. You can see my foto's on internet on www.tinyurl.com/fietsgijs. You can let me know what you think about it.. Kind regards, Gijs Eindhoven, Holland ============================================================ This is the Python Mailinglist //www.freelists.org/list/python Listmaster: Jurgen Mages jmages@xxxxxx To unsubscribe send an empty mail to python-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field. ============================================================