PS:
Actually the front hub seems to be based on a Pinion gearbox (->
https://pinion.eu ;<https://pinion.eu/>) with a custom hub/shell around it
instead of the chainring.
You can see it in this movie:
https://www.youtube.com/watch?v=Q0DXHk-kmAQ ;
<https://www.youtube.com/watch?v=Q0DXHk-kmAQ>
There are also detail pictures in this thread:
https://www.bentrideronline.com/messageboard/showthread.php?t=134281 ;
<https://www.bentrideronline.com/messageboard/showthread.php?t=134281>
Cheers,
Christian
Am 26.08.2018 um 22:34 schrieb Christian Winkgen <christian.winkgen@xxxxxxx>:
Great idea.
I have ridden the KerVelo last year in Germersheim for a few meters and not
being used to recumbents back then this was the first one I could ride
without tipping or feeling unsafe.
The only downside was that small turns cause pedal-strike quite easily.
I could imagine that your idea works, but not sure how it feels.
What about building a quick and dirty prototype without the hub gears - just
using a rigid axle from a unicycle?
If this is rideable (you can let someone try who can ride a Python or try to
learn it yourself) - you can go from there.
This looks very interesting to me. The thing I liked with the Python right
from the start is the simple concept and the compact drivetrain.
You idea is even more compact and simple - only probably harder to learn than
the KerVelo.
One more thing: Adjusting to different rider sizes probably means telescoping
the front section / front wheel from the pivot.
This is not necessary if you build it for yourself of course…
I would also consider putting the handlebars beneath the seat. This is more
relaxing and even simpler to build.
Just attach them to the front section near the pivot.
Good luck and keep us posted!
Cheers,
Christian
Am 26.08.2018 um 20:37 schrieb Vincent Bashandy
<vincent.bashandy@xxxxxxxxxxx>:
Hi,
Thanks for your feedback. That hub gear is a matter of not being on the
market rather than not being technically possible. In fact, as ‘drcorle’
said, it does already exist.
The second issue is a good point, haven’t thought about that. I have never
driven a Python, does it require a lot of power to steer? In my design it
would require about twice the force of a regular Python. This problem could
either be solved by power steering, or by moving the steering pivot under
the seat, but I don’t know what such a big trail does with the ridability??
Greets,
Vincent Bashandy
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Van: python-bounce@xxxxxxxxxxxxx <python-bounce@xxxxxxxxxxxxx> namens Karl
McCracken <karl.mccracken@xxxxxxxxxxx>
Verzonden: Sunday, August 26, 2018 5:47:26 PM
Aan: python@xxxxxxxxxxxxx
Onderwerp: [python] Re: Would my design work?
Hi -
I'm not sure this would work.
The main problem is that hub gear - I don't know of one that'll work with
cranks like that instead of a single drive sprocket. So you've no way to get
power from your left leg and into the hub.:0/
The next issue is the steering torque required. With the "standard" Python
layout, your legs have a nice long lever to act on, and crucially this is
well beyond the wheel's contact point. Your setup doesn't have this, and I'm
not convinced that the handlebars will help.
It is an intriguing design though, so don't give up on it yet!
Karl.
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From: python-bounce@xxxxxxxxxxxxx <python-bounce@xxxxxxxxxxxxx> on behalf of
Vincent Bashandy <vincent.bashandy@xxxxxxxxxxx>
Sent: Sunday, August 26, 2018 3:32:20 PM
To: python@xxxxxxxxxxxxx
Subject: [python] Would my design work?
Dear everyone and Jürgen,
Lately I got an idea in my head for a recumbent bike but I stumbled over
some problems regarding the steering system. Then I came across the website
about the Python Lowracer which convinced me that a bicycle with a steering
pivot far behind the center of the wheel was actually possible, so I began
modelling my idea. Now the first version is finished and I consider building
it, but first I need to know if this design would be stable/ridable. Is it
worth building it?
The design is different in all other python’s in that it has pedals directly
on the front wheel, using a hub gear to get gear ratio’s. I also added a
steer for stability aiding purposes and as a place to put your hands on.
This version is intended as a racer, as you can see in the first image
The dimensions can be seen in the second image.
The front wheel 28 inch, the rear wheel 20 inch. Crank length is 150mm, seat
angle is 20 degrees.
Now, the main question is, would this work?
My main concern is that the legs could strike the steering column when you
have to steer hard, but there are solutions to this. Also according to the
Open Bike wiki, the Pedal-Steer interference would be bad because the
steering pivot is not under the hip of the driver. This could be solved by
moving the pivot to the seat - and this would also solve the steering column
striking problem – but this would give a trail more than twice as big as it
already is now. This would make it completely unridable, right?
I would like to hear your opinion on this :D.
Greets,
Vincent Bashandy, Netherlands
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