Introduction: Fail: a Full Tilting 3-wheeled Cargo Bike

Picture of Fail: a Full Tilting 3-wheeled Cargo Bike
after building some "standard" cargo bikes i decided to get my hands dirty again, this time with something very special. i wanted to build an ideal cargo bike combining the stability of a three-wheeler (e.g. https://www.instructables.com/id/how-to-build-a-cargo-bike/ ) with the possibility to take curves like being on two wheels (e.g. https://www.instructables.com/id/build-a-2-wheel-cargo-bike/ ).
long story short: in the end i managed to build a bike that has the above features, but has simply become too heavy to load anything on it. plus steering is something you really have to learn with this monster:

surely it would be possible to improve this construction massively, but i think this would exceed my possibilities in regards of time and money.
BUT if some builders out there want to try their luck, here is what i learned so far and how i built this machine.

Step 1: Research

Picture of Research

the first step was to do extensive research. since i am not an engineer it took me quite some time to understand the concepts behind it. an incredible source of technical inspiration was the tilting group over at yahoo: http://autos.groups.yahoo.com/group/tilting/ although primarily concerned with tilting concepts in regards to engine driven constructions the group is surely the best place to find information about constructing a tilter.

also very inspiring are tilting tricycle constructions built before:
- the jetrike: http://www.jetrike.com
- onya cycles' front-end loader. unfortunately the website (http://onyacycles.com) seems to be dead, but here are a some impressions: http://tinyurl.com/as2cc5m
- youtube has quite some videos about tilting trikes: http://tinyurl.com/ajkp98w

Step 2: An Early Prototype

Picture of An Early Prototype
after researching and sketching a few ideas i decided to grab some parts i had lying around and started with a very simple prototype. what i learned was that building such a vehicle needs a high degree of accuracy, which was ot the case with the prototype. the consequece was that the steering mechnism locked itself every now and then.

Step 3: Building the Trike: Lean-steer Part

Picture of Building the Trike: Lean-steer Part

after building the prototype i went back to my drawing desk and made a few more sketches. this led to an improved version of the steering/tilting mechanism. back in the workshop i started building the trike.

the first part to build was the lean/steer mechanism. as you can see in the first photo the core part are ball heads which allow a tilt of 30° (2x15°) and, at the same time, the turning of the wheel axles. in the second image you can see how it tilts.

Step 4: The Frame

Picture of The Frame

building the frame was quite straightforward. as usual i cannibalized an old bike for the rear triangle and then added the front part.

Step 5: First Test Assembly

Picture of First Test Assembly

after adding the frame for the cargo basket i assembled it for the first time.

Step 6: Steering

Picture of Steering

now came the hard part: constructing the steering mechanism. i started with the usual steering design used with 2 wheel cargo bikes (see: https://www.instructables.com/id/build-a-2-wheel-cargo-bike/#step4 ) but it took me quite some time to figure out how to transmit the steering force adequately to both wheels without allowing the whole thing to lock itself in any angle. i don't want to go too much into detail here but i hope the principle is visible in the photo.

Step 7: That's It!

Picture of That's It!

as said in the introduction the whole thing is
- too heavy
- the wheels are way too far in the front and
- steering is a pain in the a**

the project took quite some time and i also spent a little bit too much money for my taste, but i'm sure i can use the knowledge i gained in the one or the other way.

Comments

PaulA23 (author)2017-05-12

So completely NOT a fail!!! Too many instructables are just "TADA! Finished product!" without giving the readers an idea of the difficulties and lessons learned in the project. The finished product is only a tiny portion of the reason(s) we enjoy these articles; the road is MUCH more informative than the destination. You materialized your concept into reality, learned some things, and COMPLETED THE PRODUCT (huge hurdle for many). This is the epitome of successful R&D - I applaud you, thank you, and encourage you to continue; you're only one moment of enlightenment away from the next big idea/design that no one else has thought of, and the world of cycling is a huge one. Excellent job!

carkat (author)PaulA232017-05-14

:-) thanks!

crazyg (author)2016-10-12

what a beast, a little confused as to how tilt steering works or doesnt work. netherthe less its good work and an entertaining and educational instructable ,

carkat (author)crazyg2016-10-14

yeah, i guess "beast" is the best description for it. a beast in the making, and to ride :-)
thanks!
c

Building bike prototypes is a dificult thing, usually you want to test the concept and end up with exhaust tubing for material, this always ends up as a "TWO BIKE", too heavy, its always a dissapointment.... I was involved with an Alan Maurer style leaner build here in christchurch, it was crazy and I never managed to steer the thing. As some feedback on yours, add some top tubes for strength and think passive vs active balance like in robots or the Segway for where it leans from as you want the axis of lean over the center of mass for stability. You could move the front wheel setup backwards to mid cargo space and build the leaner mech off that, but then it will be two wide..

I8mAll (author)2016-05-09

Wow, you say you are not an engineer but your metalwork looks spot on. Just keep on refining what is already nice work...

carkat (author)I8mAll2016-05-12

thank you!

kendall.pearson.712 (author)2015-01-12

How did you lengthen the head tube?

How are the steering arms all configured?

Thnaks. Great project

head tube: from center to the upper end is length of disc brake mount plus some clearance (eyeballed) plus mount for the ball joints. from center to lower end it has to be the same distance.

steering arms: took me quite some time to figure out: in the end it's not that hard: for the steering i calculated an ackermann-geometry and the head tubes have an angle of (if i remember correctly) 75 degrees to the ground (i.e. they are leaning slightly backwards).

thanks!

king29260 (author)2014-12-21

Thank you for sharing, even if it's not a great success , it's very useful ! As I was thinking about making a cargo bikke it helped me to avoid some mistakes. I thought about the same kind of design with the front wheel very far, which was , as you said, a bad idea .

I réally liked your front wheel system design by the way.

(sorry for the english mistakes, greetings from France)

carkat (author)king292602014-12-23

thank you!

bjørnsradio (author)2014-11-28

Really nice, just thinking about tilting cargo bike in a long version.

tjek out :

http://commutercycling.blogspot.dk/2013/12/leaning...

I let you know about my bike soon

br Peter

IdealL (author)2014-09-02

This isn't much of a fail! Actually, this is progress. I have been looking for a design like this to build an electric trike for practical transportation. I hope you become inspired to improve on your design.

carkat (author)IdealL2014-09-04

thanks! actually it seems commercial cargo bike builders catch up on that kind of steering: see here: http://www.butchersandbicycles.com/ or here: http://www.veleon.de/carving_eng.html
what is different is that the front wheels are much closer to the rider. guess this is a better solution to transmit the forces necessary for steering.

IdealL (author)carkat2014-09-04

Yeah, I figured that the wheels had to be closer, but at least that's some confirmation of how I need to design the bike.

gpcmk (author)2014-02-13

Definitely NOT a "fail". When things don't turn out as expected, I classify them as a "builder's study". Thanks for posting.

godscountry (author)2013-12-09


Philip James is the guy,he seems to know how to get these systems working right.I gather that you can't have the lean,tilt steer it.Check him out.

IAC United (author)2013-02-28

The project might be better with a mechanical steering device, like an actual car steering. It appears your not only steering the bike conventionally but the freight as well. Maybe an upright steering wheel, connected to a vertical shaft and a chain drive to connect it to the wheels. Just a thought. I like the idea.

carkat (author)IAC United2013-03-03

yeah, might be. though that makes it also more complicated to build (i guess). but you are right - i am steering the freight, too. i was thinking about the wether tilting the freight or not for a long time, but actuall i never thought of steering it or not! have to think that through...

RobertG65 (author)carkat2013-08-31

As far as the steering goes raise the linkage and set the top ball joints back 5 degrees from center and it will steer easier

RobertG65 (author)carkat2013-08-31

why not try to keep the 2 wheels up front move the seat and handle bars foward and have the basket in the rear ,,then you will loose the weight off of the steering

Hahob (author)2013-07-13

Very nice design, again! I noticed that you have put Vienna as your location, same as mine. Is it possible to have a look irl at your bikes? Anyways, thanks for uploading!

carkat (author)Hahob 2013-07-13

hey, yes sure! i'm currently out of town 'til mid august but afterwards would be cool. PM me if this would be ok with you :-)

FrozenIce (author)2013-03-01

Ever considered making Batman's Batpod using this design? i honestly think you are on to something with this steering design. It rides far more elegantly than a normal bike. Keep up the good work. 5*

carkat (author)FrozenIce2013-03-03

thank you!

mcsxr2 (author)2013-02-28

Nice job ! You are very close to making it work. There are some great suggestions here to try. These links are very helpful. Gregs' early work with three wheelers is very well documented. The recumbent site is loaded with info. But when it comes to learning bike geometry Jetrike is the man,as well as Fleettrikes.
I'm building a front wheel drive tadpole with a 36" front wheel!! and two 20" rear wheels using Jetrikes lean system. A lot of trial and error as well.
Don't give up. ( I've been working on mine for years)



http://www.fleettrikes.com

.http://www.recumbents.com

Greg Kolodziejzyk

carkat (author)mcsxr22013-03-03

hi,
thanks a lot! lets see what will happen. currently i'm too busy (3 jobs and a family) to work on it again, but i guess there will be less busy times again. at these times i often catch up with older projects that stick in my head :-)

mcsxr2 (author)2013-02-28

Sorry, mines a delta layout not a tadpole.

espdp2 (author)2013-02-27

Wow! Still a good project. The main difference I see between your and the front end loader is the electric power. I'll bet if you tweak the steering a bit and add an electric kit (I know, more money), it will transform into something much more satisfactory. I recommend 800-1,000 watts of power. :-)

carkat (author)espdp22013-02-28

right, but having a motor in it transforms the whole thing totally. i tried an electric cargo bike once and recognised that it behaves very different from a usual human powered one. i guess i would have to redesign the whole trike to keep up with the forces of the motor.

Woodenbikes (author)2013-02-27

Its great to see the experiments and hear your findings! I don't know much about trike steering but it may be fairly easy to modify the head angle ( relaxing it to a shallower angle) to give a little more trail or caster. Or alternatively steepen the head angle to eliminate the trail. I wonder if that would ease or burden the steering.

carkat (author)Woodenbikes2013-02-28

yeah, this is surely something that should be figured out in this construction. and i think it really might improve steering, but i guess there are other flaws, too.

carter5521 (author)2013-02-27

I know you posted that as a failure, but that could be awesome as "no-snow" dog sled. I Bikejor with my dogs and have been looking for plans or ideas for a bike-sled for the dogs. Something you can steer and has brakes, but can haul stuff much like dog sled. You have a fantastic idea here! Great job! :)

carkat (author)carter55212013-02-28

great idea! maybe i should move to greenland and do a collaborative project with somebody there :-) would surely be fun!

jolshefsky (author)2013-02-27

I wonder if your experience with the steering being a pain could be because you keep the steering wheels parallel. Although it's not necessary on a trike, I find it helps to use an Ackermann-styled mechanism: if the wheel on the inside of a turn turns tighter than the outside wheel, the steering feels more natural. I think that's because that steering geometry keeps the three wheels tracking the same turning circle whereas parallel wheels have the front wheels tracking a tangential line to the turning circle while the rear wheel tracks the circle itself leading to scrubbing or friction. I'm guessing that changing the steering direction while in motion is difficult and increases as speed increases. Ackermann geometry doesn't have that issue. I think you can also tune it to slightly favor tracking straight but I'm not sure how to do it.

carkat (author)jolshefsky2013-02-28

hi,
in fact it is an Ackermann geometry, it's just not visible in the photos. the problem with steering, i think, arises because of the length of the vehicle and the fact that the force you apply by turning the handlebars has to travel quite a long way to get to the wheels. also it's totally crucial to build with -for a tinkerer like me- extreme accuracy. if it's not that precise, force gets lost and the loss adds up with every inaccuracy.
thanks!

dZed (author)2013-02-26

Awesome build. I applaud you for posting about your "failure" -- lots to learn from those types of experience.

carkat (author)dZed2013-02-27

thanks a lot!

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