No 'bent for me! It ain't no piece of art!

[Harry Spatz]

I was at a party last week end and came across a fairly avid cyclist. I told him I rode a 'bent and
described my Barcroft Dakota as comfortable and fast. He was familiar with Bacchetta and Vision. He
said that he would consider trying one, but no way would buy one. I asked him why he would summarily
dismiss one when he hadn't even tried it. He said they were aesthetically unpleasing and elaborated
that the long chain was unsightly! I thought he was joking with me, but found he was serious. I've
heard lots of reasons to dismiss a 'bent, but I think that this one beats them all!

 

[Mikael Seierup]

"Harry Spatz" skrev...
> I was at a party last week end and came across a fairly avid cyclist. I told him I rode a 'bent
> and described my Barcroft Dakota as comfortable and fast. He was familiar with Bacchetta and
> Vision. He said that he would consider trying one, but no way would buy one. I asked him why he
> would summarily dismiss one when he hadn't even tried it. He said they were aesthetically
> unpleasing and elaborated that the long chain was unsightly! I thought he was joking with me, but
> found he was serious. I've heard lots of reasons to dismiss a 'bent, but I think that this one
> beats them all!

Show him this one: http://www.liegeradinfo.de/chinkara.jpg Hard to learn to ride but the chain is
short. ;o)

Mikael

 

[Bill Patterson]

Mikael Seierup wrote:

> Show him this one: http://www.liegeradinfo.de/chinkara.jpg Hard to learn to ride but the chain is
> short. ;o)
>
> Mikael

I lust for a Chinkara. I first rode one at People Movers in LA LA land. Great bike.

I think it would have a little wheel spin in the mountains. Most front drives around here are low
to reduce weight shift on the hills.

--
Outlaw power steering

See some Bikes At:

http://home.earthlink.net/~wm.patterson/index.html

Class and Helicopter

http://www.calpoly.edu/~wpatters/

Reply to [email protected]

 

[meb]

Originally posted by Bill Patterson
Mikael Seierup wrote:

> Show him this one: http://www.liegeradinfo.de/chinkara.jpg Hard to learn to ride but the chain is
> short. ;o)
>
> Mikael

I lust for a Chinkara. I first rode one at People Movers in LA LA land. Great bike.

I think it would have a little wheel spin in the mountains. Most front drives around here are low
to reduce weight shift on the hills.

--
Outlaw power steering

See some Bikes At:

http://home.earthlink.net/~wm.patterson/index.html

Class and Helicopter

http://www.calpoly.edu/~wpatters/

Reply to [email protected]

Lot of clearance between the top tube and front wheel. Is there a lot of suspension travel?

Steering implementation is not conclusive from a single photo, is this a mid-steer like the Python?

Is the Chinkara a commercial model or a prototype/homebuilt?

 

[watsonglenn]

I actually see his point . I agree and that is why I do not ride a long wheel base. To me the ugliest part of any bike is the chain. If only the whole thing coud be hidden in the frame somehow.

 

[Bill Patterson]

meb wrote:
> Lot of clearance between the top tube and front wheel. Is there a lot of suspension travel?
|t has suspension on both ends. Smooth ride.
>
> Steering implementation is not conclusive from a single photo, is this a mid-steer like
> the Python?
>
The steering axis is under the front seat. I'm not sure about the Python or mid'steer.

> Is the Chinkara a commercial model or a prototype/homebuilt?
It was a commercial model, A direct copy of the Flevo.
>
>
>
> --
>
>

--
Outlaw power steering

See some Bikes At:

http://home.earthlink.net/~wm.patterson/index.html

Class and Helicopter

http://www.calpoly.edu/~wpatters/

Reply to [email protected]

 

[meb]

Originally posted by Bill Patterson
meb wrote:
> Lot of clearance between the top tube and front wheel. Is there a lot of suspension travel?
|t has suspension on both ends. Smooth ride.
>
> Steering implementation is not conclusive from a single photo, is this a mid-steer like
> the Python?
>
The steering axis is under the front seat. I'm not sure about the Python or mid'steer.

> Is the Chinkara a commercial model or a prototype/homebuilt?
It was a commercial model, A direct copy of the Flevo.

Here's a link to the Python which is a lowracer with a steering similar the Chinkara:

http://www.python.de.tt/

 

[Bill Patterson]

If you are riding the Python, please let me know how it is.
If you are building the python, DON'T.

The bike will be dangerous. A lilne through the steering
axis shoul intersect the ground in front of the front wheel
contact point. That's called trail. A bike with negative
trail will always try to turn away front straignt ahead.

I have had several people ask why their "mid steer" bikes
didn't work. That is why.

The steering of the Python is nothing like the Chinkara.
Believe me.
> Here's a link to the Python which is a lowracer with a
> steering similar the Chinkara:
>
> http://www.python.de.tt/
>
>
>
> --
>
>

--
Outlaw power steering

See some Bikes At:

http://home.earthlink.net/~wm.patterson/index.html

Class and Helicopter

http://www.calpoly.edu/~wpatters/

Reply to [email protected]

 

[Torben Scheel]

"Bill Patterson" <[email protected]> wrote in message
news:[email protected]...
> If you are riding the Python, please let me know how it
> is. If you are building the python, DON'T.
>
> The bike will be dangerous. A lilne through the steering
> axis shoul intersect the ground in front of the front
> wheel contact point. That's called trail. A bike with
> negative trail will always try to turn away front
> straignt ahead.
>
> I have had several people ask why their "mid steer" bikes
> didn't work. That is why.
>
> The steering of the Python is nothing like the Chinkara.
> Believe me.

No, it uses another priciple - the frame axle is below the
line between the wheel axles and it is tilted. The weight of
the rider stabilizes the bike. Turning lifts the rider. Take
a look at the pics on the pages, I believe it does work.

Tomorrow I get the rest of the tubing I need to build one,
and I hope I'm right ;-)

Regards, Torben

 

[Juergen]

Hi Bill,

I have had a lot of discussions about the negative trail of
the python.

http://www.python.tieflieger.net/geometry.html

tries to work out the point, why the python IS SAVE.

The NT is only one of several effects and forces that can
destablilize ore stabilize a bike in movement.

In the case of the python the "hanging pendulum" effect
overpowers the NT effect easily.

During 6000 km of daily usage, I did not had any problem
with the safety of this bike. A lot of people around me
have started to build their own python. This should speak
for itself.

Regards,

Jürgen.

 

[Dave Larrington]

watsonglenn wrote:

> I actually see his point . I agree and that is why I do
> not ride a long wheel base.

Eh? The chain length depends on the distance between the
bottom bracket and the drive wheel, which is independent of
the distance between the axles.

> To me the ugliest part of any bike is the chain. If only
> the whole thing coud be hidden in the frame somehow.

http://www.legslarry.beerdrinkers.co.uk/images/pix/Dave/big-
/bucher.jpg

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Mark Stonich]

[email protected] (juergen) wrote in message news:<[email protected]>...
> Hi Bill,
>
> I have had a lot of discussions about the negative trail
> of the python.

My concern about your bike is that it may be hard to ride
or unstable due to the steering system.

If so, this will be interpreted by some as validation for
the commonly believed, but absolutely innacurate, myth that
all negative trail bicycles are unstable.

A conventionally steered LWB with enough rake to have
negative trail has self centering "anti-wheelflop" and feels
wonderfully stable. Anyone who disputes this is invited to
come to Minnesota and ride Carl Gulbronson's TE clone.

However you do not want to have negative trail on a bike
with a frame mounted fairing, as it will react wrongly to
crosswinds. Turning the wheel upwind, instead of downwind
which is what you need.

 

[Bill Patterson]

Mark Stonich wrote: If so, this will be interpreted by some
as validation for the
> commonly believed, but absolutely innacurate, myth that
> all negative trail bicycles are unstable.
>

My concern is "control spring" or what you call "centering
force". A negative trail bike would need more tiller or
attached bungee cords etc to provide enough control spring.

> A conventionally steered LWB with enough rake to have
> negative trail has self centering "anti-wheelflop" and
> feels wonderfully stable.
Is wheel flop the low speed tendancy to turn further when
the handlebar is turned (positive K1) or is it the tendancy
to turn towards the frame rotation? (fork flop). I vote
against K1 and for a certain abount of fork flop. Fork flop
acts as an autopilot and helps the rider stay upright.

> Anyone who disputes this is invited to come to Minnesota
> and ride Carl Gulbronson's TE clone.

Would love to some day.
>
> However you do not want to have negative trail on a bike
> with a frame mounted fairing, as it will react wrongly to
> crosswinds. Turning the wheel upwind, instead of downwind
> which is what you need.

Fully agree on this one.

I too can't wait to hear how the python handles.
--
Outlaw power steering

See some Bikes At:

http://home.earthlink.net/~wm.patterson/index.html

Class and Helicopter

http://www.calpoly.edu/~wpatters/

Reply to [email protected]

 

[Bill Patterson]

I have a tendency to spell better with my glasses on.

Bill Patterson wrote:

>
>
> Mark Stonich wrote: If so, this will be interpreted by
> some as validation for the
>
>> commonly believed, but absolutely innacurate, myth that
>> all negative trail bicycles are unstable.
>>
>
> My concern is "control spring" or what you call
> "centering force". A negative trail bike would need more
> tiller or attached bungee cords etc to provide enough
> control spring.
>
>> A conventionally steered LWB with enough rake to have
>> negative trail has self centering "anti-wheelflop" and
>> feels wonderfully stable.
>
> Is wheel flop the low speed tendancy to turn further when
> the handlebar is turned (positive K1) or is it the
> tendancy to turn towards the frame rotation? (fork flop).
> I vote against K1 and for a certain abount of fork flop.
> Fork flop acts as an autopilot and helps the rider stay
> upright.
>
>> Anyone who disputes this is invited to come to Minnesota
>> and ride Carl Gulbronson's TE clone.
>
>
> Would love to some day.
>
>>
>> However you do not want to have negative trail on a bike
>> with a frame mounted fairing, as it will react wrongly to
>> crosswinds. Turning the wheel upwind, instead of downwind
>> which is what you need.
>
>
> Fully agree on this one.
>
> I too can't wait to hear how the python handles.

--
Outlaw power steering

See some Bikes At:

http://home.earthlink.net/~wm.patterson/index.html

Class and Helicopter

http://www.calpoly.edu/~wpatters/

Reply to [email protected]

 

[meb]

Originally posted by Bill Patterson
If you are riding the Python, please let me know how it is.
If you are building the python, DON'T.

Unfortunately, not a rider, just an admirer of Juergen's work.

As you've discovered, Juergen is a poster here.

I may experiment with a fwd lwb lowracer in a year or two.

 

[Reclinedrelic]

Hi

Mark and Bill, both your theories about bike handling assume
the use of handlebars and hands for steering. As you will
see from the information on Jurgen's web site, the Python is
steered only by ones legs. There are no handlebars. With
regards to Bills theory, the control spring would be felt
through the legs. Would this change the equations? How would
one design such a bike to optimize control, or are you
saying that it is impossible?

I've just about finished building one of these bikes and my
first ride tells me that it is not like riding a regular
recumbent. I have previously built a moving boom FWD with
some success. That bike had a learning curve as well. The
python has even more of a learning curve, but if Jurgen can
ride his more than 6000 km then I can ride mine too!

A picture of my python is at www.odyssey.on.ca/~mchannon

Regards,

Mike Channon London, Ontario, Canada

Bill Patterson <[email protected]> wrote in message
news:<[email protected]>...
> Mark Stonich wrote: If so, this will be interpreted by
> some as validation for the
> > commonly believed, but absolutely innacurate, myth that
> > all negative trail bicycles are unstable.
> >
>
> My concern is "control spring" or what you call
> "centering force". A negative trail bike would need more
> tiller or attached bungee cords etc to provide enough
> control spring.
>
> > A conventionally steered LWB with enough rake to have
> > negative trail has self centering "anti-wheelflop" and
> > feels wonderfully stable.
> Is wheel flop the low speed tendancy to turn further when
> the handlebar is turned (positive K1) or is it the
> tendancy to turn towards the frame rotation? (fork flop).
> I vote against K1 and for a certain abount of fork flop.
> Fork flop acts as an autopilot and helps the rider stay
> upright.
>
> > Anyone who disputes this is invited to come to Minnesota
> > and ride Carl Gulbronson's TE clone.
>
> Would love to some day.
> >
> > However you do not want to have negative trail on a bike
> > with a frame mounted fairing, as it will react wrongly
> > to crosswinds. Turning the wheel upwind, instead of
> > downwind which is what you need.
>
> Fully agree on this one.
>
> I too can't wait to hear how the python handles.
> --
> Outlaw power steering
>
> See some Bikes At:
>
> http://home.earthlink.net/~wm.patterson/index.html
>
>
> Class and Helicopter
>
> http://www.calpoly.edu/~wpatters/
>
> Reply to [email protected]