[python] another newcomer
- From: Thomas P Jahn <tpj@xxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Thu, 18 Jan 2007 15:07:33 +0100
Dear pythoniacs
I just shortly want to introduce myself. My name
is Thomas and I live in Copenhagen. I learned the
python to know via Dirk, when he built his baby
and helped building several of them in our
kvisten club in København. I must say, that I was
immediately impressed by the construction and
basic idea. Yesterday I read a thread in a
lowracer forum, discussing the issue that riding
a lowracer can be embarrassing for some people.
And I somehow know this feeling. But the python
seems different. The rider doesn't look so clumsy
on the bike. Maybe riding the python requires
that you are relaxed. And here I have to stop
talking, because I have never tried it myself.
Not yet.
It was just recently that I found the mailing
list through a search in the Internet. And first
of all I have to express my respect. Your
projects and in particular Jürgen's page with all
the various measures on the python survey and
links to the original sites is very useful.
I also noticed that just recently, this mailing
list has been exploding. Okay, it is a www. But
anyway, compared to the very first start, this
list has certainly attracted a lot of attention.
And now I am just one of the many many readers to
say hello. Anyway, I guess, that was part of the
purpose by establishing this platform. And I hope
it will continue.
So, obviously I am soon going to build my python.
And I have prepared a number of things. I
collected something like 5 donor bikes. Should be
a fair starting point. I am about to make the
wheels. In 20''. The overall goal of the project
will be to use as many bike parts as possible. I
figured that it will be fairly easy without being
too picky on the source material to make front
parts from racing-bike back part and back parts
from MTB forks. So the main challenge will be in
the construction of the middle part. And just
here, there is, as you know, as many solutions as
there are constructors.
Maybe you could help me in a few questions:
What is the significance of the BB/seat
difference? Does it have any impact on stability
/ centering? Or is it more about the comfort and
related to the seat angle? In principle, 20''
wheels would allow the BB to be lower than the
seat. I have not been able to find such examples.
But the values in Jürgen's project survey rank
from 5 to 29,5 cm.
I am considering a construction, where the pivot
angle is adjustable. At the same time, it could
also be linked to shock absorption. In that way,
it will have to be adjusted to the weight of the
rider to have a kind of resting position. But the
pivot angle will then still (again depending on
the features of the shock absorber - should
certainly be rather stiff) be under constant
change. Compressing the absorber would reduce the
pivot angle and consequently the negative trail
and vice versa. Has anybody experience with that?
Would that kick the rider off the bike? Do you
have any idea how this would affect stirring
dynamics? Or shall I make the test? J
The last question for now: The wheels base! I
understand that the wheelbase will influence the
self-centering effect. But apparently much less
than the pivot angle. So, is there any limit for
the wheelbase in any direction? And why?
I hope, you still have the power to answer the
many questions of all these newcomers.
Cheers
Thomas
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