Thank you all!
My plan is 20" wheels, about 80 cm of track width (legal limit is 90 cm overall
and I'd use standard front hubs with axles fastened at both ends), wheelbase
about the same as Vi's machine, cargo capacity at least 100 kg (plus rider),
seat as low as possible (that means just above main beam which is at wheel hub
height), weight under 30 kg if possible (the value to improve upon is my
current setup of 16 kg bike + 17 kg trailer = 33 kg), disk brake front, drum
brakes rear, underseat handlebars attached to the front fork.
Target environment is standard streets and roads with occassional bits of
cyclepath when available.
According to Vi's video, it seems like it's OK to just lean the upper body
(legs lean with the front wheel anyway) to get enough stability even with
narrower track width than mine. So leaning of the seat is not needed - good,
that eliminates whole lot of design difficulties. Riding it would be OK for me
(I can ride Python bikes), but it would need secure locking for others and low
speeds.
Trailers are a good solution if one can't have a dedicated cargo vehicle, but
otherwise they're not very practical (in my opinion). Small trike + big trailer
= two wheels more than necessary (more weight and drag). Big trike + big
trailer = too much weight to be able to pull (and hard or impossible to push).
Anything + trailer = two heavily loaded nonbraked wheels, and also two vehicles
to park.
If I ever build this, I promise to post pictures and feedback at Openbike :-).
Mirek
Od: "paul needham" <paul.2.needham@xxxxxxxxx>============================================================
Komu: python@xxxxxxxxxxxxx
Datum: 28.11.2018 09:05
Předmět: [python] Re: Python trike cornering stability
Mirek
First the trike stability depends on height of c of g from ground [ on a
recumbent general through the riders navel ]
Width of trike foot print where vertical line through c of g touches
ground [ foot print is triangle drawn between tyre contact patches ]
Also speed and angle of corner.
If you make the trike tilt in any way you have built a Python bike and
will have to learn to ride it !
So what height do you want the seat from ground ?
Can the trike not tow a trailer , lot easier than towing with a bike ?
What sort of load do you anticipate ?
Where are you riding ? roads , dedicated cycle paths etc ?
all the best Paul
Od: "Steffen R" <big.skangster@xxxxxxxxx>
Komu: python@xxxxxxxxxxxxx
Datum: 27.11.2018 19:09
Předmět: [python] Re: Python trike cornering stability
Hi Mirek,
I hadn't had big issues with mine as far as I remember. But the bike itself
was kind of a load already its 40+ kg. It also had a short and quite wide
wheelbase.
Am 27.11.2018 07:51 schrieb "Vi Vuong" <dmarc-noreply@xxxxxxxxxxxxx>:
Hi Mirek,
I experimented with a trike with off-center front wheel. It was more
stable going into right corner as I can lean in. See
https://youtu.be/as5fB8cQX7g
Left turn was okay at normal speed.
Vi
On Nov 26, 2018, at 12:16 PM, <mircosoft@xxxxxxxxxx> <mircosoft@xxxxxxxxxx>
wrote:
Hello fellow pythoneers,
I'm looking for someone with personal experience with a non-tilting cargo
trike, like this:
http://en.openbike.org/wiki/File:Gavin-Katts.jpg
My goal is to replace a bike+trailer combo by something equally capacious,
but faster to ride (i.e. lighter and more aero), easier to start, stop and
park.
The only problem is I have no idea what it will do in high speed turns.
Long wheelbase, centre of mass closer to the single front wheel than rear
axle, front wheel contact patch moving into the turn - everything says it
would topple easily when not loaded heavily. I can live with some
instability, the question is: would I have to slow down for every turn so
much that it offsets all the aero and weight benefits over the bike and
trailer?
Tilting front end is also an option, but I'd prefer to get along without
one if possible.
Thank you for any input.
Regards
Mirek
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