[python] Re: Svar: Re: children's python

Thomas Paul Jahn wrote:

Hej Dirk,

Luka's first trial reminded a lot of his first time on an upright. He was very 
eager but it will take some time!!

The bike is a little too big still and so is the seat. He says, the seat is 
hard. The latter can be solved. The former will solve itself.
The front part is rather heavy. With a Sram 5 speed hub. Am I surprised?!
And the pivot made of brass bushes is pretty rigid. With his low weight, the 
self centering is minimal.
Also the long rear part probably reduces the self centering. I wonder if I 
simply cut it shorter.
On my bike the self centering is also minimal - just enough to keep the front piece upright when sitting on it. I don't feel this is a problem at all, on the contrary, I like it because it allows for quick & sharp turns. Maybe Luka just needs the chance to learn it first a bit?
The weight of the front part should be as low as possible. Why should the sram hub have something to do with that? To me the bike looks already quite light - the tube at the front could be shortened, but then you would need to weld it back as Luca gets older.
You could shorten the rear, yes. It looks anyway disproportional long compared to the rest of the bike. But I think the self centering will get smaller. Do you have some data about the bike, I can calculate a comparisation to my bike. I need: 
* wheel size
* pivot  angle
* trail
* seat height
* wheel base

And at the axis of the rear swing, or at the back wheel, I probably fix some 
supporting wheels to each side. So I don't have to walk bended down next to the 
bike, while Luka is doing his first exercises.



And the seat lean should be less inclined for him to reach the ground with his 
hands. I just hesitated reducing the inclination, as the beginner is not 
relaxed enough to go very recumbent. I seems now it would be better anyway...

What do you think?
May be better to recline the seat (and not add support wheels), so he can touch the ground so he kind find his own balance. 


About the seat: It was extremely easy to make and is very rigid and stable. 
After assembling, I glued it with expoxy. I will definetly make one for my 
python as well, where I still lack the proper seat solution. The wooden seat is 
very easy to attach too. Because its construction can be adapted to the bike 
structure. It seems the idea for the seat brought me a large step further, 
while doing the final work on the bike. I strongly recommend it:
http://hebike.borec.cz/sedlo.htm
Very interesting solution and very light!!! Don't understand the language but the scale I can read: 616gr. How well does the seat fit (lumber support)? 

dirk

============================================================

This is the Python Mailinglist

http://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.

============================================================

Other related posts: