To save you some dead ends: this design will not work for your intended
purpose. Rear wheel steering might work on a non-tilting trike, but its track
must be wide enough to resist tipping over - say 70 cm or more. And definitely
no lean steering. With the mountainboard rear axle, if you lean to one side,
the rear end starts to move in the opposite direction, increasing your lean -
that's a positive feedback loop which ends with you laying on the ground. Then
there's the rolling resistance of two small wheels - not the best to cover long
Tiny size and foldability are usually the exact opposite of efficiency and
cargo capacity, but there may be ways to combine them all into one package. I
think a 26" front wheel would be too big for easy folding, 20" would be better
(still OK for most gear hubs). Rear wheels should be at least 16" to roll
easily, but that's just my opinion, I have never tried anything smaller than
20". They could be mounted on two long cantilever arms, providing wide track
for stability, which could fold flat next to the front wheel. Steering could be
standard Python design with a pivot between the seat and the front wheel
(doesn't need handlebars), or the FW and seat could lean/steer together while
the rear axle stays horizontal (needs handlebars on the rear part).
I'll try to make some sketches.
On June 6, 2020 7:41:23 PM GMT+02:00, Tihamer Juhasz <balamber@xxxxxxxxx> wrote:
I am not an expert in any recumbent related field, all my experience is
building 8 different types/geometries of recumbent bikes (including one
sitting/recumbent tandem). I haven't built a trike (python geometry or
otherwise), I haven't built a rear-wheel-steering bike or trike. I can
give you my thoughts and ideas. They are just best guesses, so please
get limited by them.
This is a very ambitious project as a first build. It has many unknowns
it will be challenging. For a first build, I would copy an existing
because that would give me the best shot at getting something decent
You will definitely need to rebuild or at least modify it heavily in
building process (especially since it's your first build and it is an
untested design), so plan for that in your estimated effort and budget.
There aren't many rear-wheel-steering trikes and just one tested RWS
recumbent bike in the world as far as I know. Search for RWS trike and
can check them out. RWS has many challenges, I am no expert in it, but
steering is no easy thing. You can find information on this topic in a
To turn on a skateboard I think that you pivot the board more than you
pivot the body for the desired turning effect. While in a turn, your
is at an angle to counteract the centrifugal force in function of your
speed, and the board is at another angle to achieve the turning
the wheels. I think that these two angles are different on a
but they will be the same on a trike if you don't apply some fancy
mechanism to have a bigger board tilt than bike tilt. This is just my
guess, but please check it out. The body/bike tilt depends on speed and
turning radius, so there is some thinking there to do to get this
On the other hand, I was almost always told that my designs won't work,
many of them worked because I did my research and put in the hours to
it work. Cutting up and welding together again is included in the
so plan for that. Good luck and keep us posted on your progress!
On Sat, Jun 6, 2020 at 3:09 PM Matthieu Chastel <
First and for most, congratulation and thank you very much for the
fantastic website you created and all the great information you
there. I also wish that the ongoing crisis does not affect you toomuch!
Following Steve Nurse advice, I am contacting you hopping you might
interesting in, and may have relevant critical advices about arecumbent
trike I have been thinking about for few months and hope to buildbellow)
eventually. I have never seen the design I made (see enclosed or
and I am afraid that the steering I want to try won't besufficient...
hence the need for support before investing the little money I haveinto it
( I am just finishing my studies...). I am now doing a volunteeringwork in
a farm, hence, I might have the best and only opportunity to build itmeans.
before a long while.
I spend quite some time thinking about "sustainable" transportation
This led me on the design draft you will find enclosed (and bellow).The
main idea is to have a comfortable and efficient bike able to do manyalso
kilometres, ideally able to take a 60liter bag or more on it, but
"tiny"/"foldable" to take the train with it and carry it around forI
potential long trekking adventures (as well as every day vehicle)...
don't think that today's "folding bikes" really tackle thosecriteria...
I dream to build the frame in wood, a material that I really like
above all, that I know more about than metal (and I think I will haveof
easier access to the tools it will require). The rest would be made
off-the-shelf pieces put together... So far, I plan to use aninternal gear
hub with paddle break (nexus 8 most probably, or 7??) in a 26" wheelon the
front limiting lose wires around. At the back, I intend to use awith
mountainboard technology (
wheels as small/flat as possible and wheels that can be mounted on(this
bring me to 6,5 inch or 8" mountainboard wheels/tire or I need tobuild my
own wheels and find some 12mm axis hub...). Perhaps a longboard withtire
wheels (like Nordic Roller wheels) would be lighter/more efficient?(here
Initially, I dreamt that this mountainboard truck would be my only
steering/tilting/suspension system, all in one! But I start to doubt
are links toward the closest project I can findFrankenboard|
https://www.youtube.com/watch?v=j6nIX1dQ-bk and to 3 wheel
C8080 70kv| 12s| VESC| MBS Matrix| Custom 9 layer vacuum press<https://electric-skateboard.builders/t/3-wheel-frankenboard-c8080-70kv-12s-vesc-mbs-matrix-custom-9-layer-vacuum-press/1366/6>
and will try to contact the person). It is the most critical part ofthis
project and part for which I would be very grateful for your (orfriends of
yours in the domain) advices.no
I like the idea because I would have very little metal pieces to use,
need for any steering handle and I would have a kind of tiltingsome
effect/advantages... But mountainboard wheels risk to create quite
drag (I found some "road wheels but they remain very large) and I amafraid
it won't give me enough turning radius... To avoid this turningissue:
- I can use very soft strings and make the angle of the truck/bikestraight
fixation steep but it is a risk of riding like a fish when I am on
roads... It might be possible to create a system to adjust thestrengths of
the strings at any time while ridding though... That might be arelevant
- I can reduce the front-back wheel distance but only within a good
stability length limit!
Mixing those 2 worlds - mountainboard/bike - is risky I guess and I
have any old or scrap material with which I could try a prototype ormake
proper measurements before buying the final material unfortunately. Ialso
dreamt to use second hand material as much as I could but I won'thave
time for this unfortunately and the virus crisis does not helpneither...
Finally, I intend to split the "front wheel + transmission part"
"main axis + back wheel + seat part" in two pieces. The joint wouldbe
bellow the bottom of the rider more or less. Those 2 parts could thenbe
carried separately for transportation. When disassembled, I wouldthus
have 1 wheel in one hand and, on the other one, or attachedvertically on
the side of a back pack, the "main axis", with 2 "bars" normally usedto
make the seat just around the rider's spine now folded along thismain axis
and the mountainboard truck at the end of this same axis. Of course,this
separation will bring fragility and/or weight! I could use thisimprove
"separation" point to create a steering on the front wheel and thus
steering... but I don't think pedal breaks on a steering wheel is asafe
I hope that, thanks to the draft scheme bellow, this long and
messy description in my broken English will make sense to you. I amhappy
to give more details or reformulate later!and
If, one day, this project becomes reality, I shall share it (plans
pictures) opensource of course!time and
I would be very grateful to receive your comments if you have the
the energy. Do not hesitate to forward it to other relevant riders ifyou
think it can help (also mountainboard riders perhaps?).
I remain at your disposal for any questions you may have.
Looking forward to hearing from you,
Matthieu (from France)
(whats'app 0033 782 178 800
PS: I am happy to subscribe to the mailing list!
[image: Image en ligne]