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

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

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

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

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

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

Step 6: 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!

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

[azapplewhite]

The pair of center pivots you used are super simple, a cylinder than then some sort of white plastic bearing? Are those stock parts or something you borrowed from another application?
(I wish I could weld as nicely as you do, you make this build look easy!)

FWIW, attached is a picture of my FAIL. It actually rides really nicely but it too unstable on uneven pavement. Going to change the steering to something VERY similar to what you have for your cargo bike.

[carkat]

that looks awesome! about the pivots: these are not bearings, that's just some kind of plastic i prepared on a lathe. i don't remember where i got the idea from, but if i recall correctly this is some plastic that can be used for purposes like this. maybe if you know somebody who knows about the different kinds of plastic they might help? or maybe somebody of the community here has more knowledge and is willing to share it?
anyway - thanks a lot for sharing your build!

[azapplewhite]

This is a super great build, I am going build something similar and hope to leverage your lessons learned! I was concerned about using rod ends for the steering mech, they are good at pivoting but am worried about the resistance to rotating. Did they actually turn/rotate pretty easily or did you have a lot of resistance??

[carkat]

rotation was easy. of course it's probably not comparable to a ball bearing but there's so much force on these rod ends while steering that you don't recognize any resistance.

[azapplewhite]

Thanks! I have another question but will ask that that in a seperate thread.

[jimmytvf]

Not a fail at all... You say:
as said in the introduction the whole thing is
- too heavy
+ is steel, so it's heavy, not much to do about it. Maybe change the cargo frame to some aluminum square tubing and bolt it to the steel frame and same some weight

- the wheels are way too far in the front
+ You have a space between the cargo frame and the steering mechanism. widening the steering could solve that, or smaller wheels

- steering is a pain in the a**
+ instead of the direct drive steering you made, attach a lever at the steering rod

Check some cargo "fiets" as an Holland reference

[PaulA23]

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]

:-) thanks!

[crazyg]

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]

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

[DownAndOutInChristchurchNZ]

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]

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

[carkat]

thank you!

[kendall.pearson.712]

How did you lengthen the head tube?

How are the steering arms all configured?

Thnaks. Great project

[carkat]

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]

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]

thank you!

[bjørnsradio]

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]

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]

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.