Hi Jürgen, Dear All,yes, of cause there are pictures - I just hope they will make it through the volume limit. I also added the measurements generally taken for the Project survey. I would be nice if you would include them.
28" Python -current- 20"_Python
Roll-out 4/2010 2/2011
Pivot-Angle 62,5 62
Trail 33 22
Seat-Height 25 27
BB-Seat 30 31
Ground-Clearance 11 14
Wheelbase 137 90
kg 16,9 13,9
BB-FWA 40 53
Turning-Circle >6m 1,5
Front Tubing 50x20 50x20
Wheelsize 28 (622) 20 (406)
CG (%) 54 46
Generally the two pythons ride quite different.
The old 28" version is hard to ride if tight corners need to be
mastered. But on reasonable strait lanes, it runs just great and really
fast.
The reason for of the huge turning circle is that the front mudgard
touches the Seat very early.
This bike sports a rear suspension, but it is a bit different from
Jürgens construction.
The 20" version is quite different, as is to expect. The short wheelbase and the fact that the front part goes under the seat while cornering, the front part can bend 90*. In practice, doing some continuous circles of about 2,5m diameter at a rather unreasonable speed - if you don't get thick. Top Speed is 44km/h yesterday, 8th and highest gear and most probable as fast as it can go.
The bike does not have a suspension, but rather thick tires (20" x 1,9). The measured speeds are, obviously, only short term sprints, not even 200m.The pivots of the two bikes are quite different. The 28" Python uses industry standard ball bearings. They worked great, had no play - but there problem is rust. After this winter, they are nearly finished.
The 20" Python use standard 1 1/4 head tube bearings.The front part of the 20" Python actually comes from the sailing python trike I started last autumn. I had postponed the project though the winter but still have the two trike rear parts - one 130cm wide the other 85cm. Maybe it is some kind of python option system bike :-). The two trikes and the bike share the front part as well as the rear wheels. Even for the bike. If you take a close look at the rear wheel, you see the single sided attachment.
The front tubing of 50x20 might sound over sized, but since the material is only standard grade construction Aluminum Alloy (AlMgSi0.5 or something) this is required.
Gerald On 18.3.11 22:33 , Jürgen Mages wrote:
Thanks Gerald,while pushing my P3, e.g. through a pedestrian zone, I rarely apply downwards pressure to the back of the seat (which is my handle). It is more like a smooth sidewards shifting to keep the bike on its track.However, of course, this pushable/rideable rule is just a rule of thumb ...Cheers, Jürgen. PS: Any pictures of your specimens available?Hi Vi, Hi Jürgen, I am not sure about the pushable requirement. Maybe a python beeing pushable is an indication that the pivot angle is right, but it seems, just that a python is rideable does not ensure it is also pushable. I do own two such specimens. Both of them ride quite nice and I do so in public traffic. For a python to be pushable, I think, beside having the pivot angle right you need to be able to put sufficient weight on the pivot while pushing. If the back of the seat is to far back, you may not be able to. Gerald============================================================ This is the Python Mailinglist //www.freelists.org/list/python Listmaster: J�rgen Mages jmages@xxxxxx To unsubscribe send an empty mail to python-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field. ============================================================
Attachment:
Geralds_20_Zoll_Python.jpg
Description: JPEG image
Attachment:
Geralds_28_Zoll_Python.JPG
Description: JPEG image
