three years ago i bought a trailer to get my son to our swimming-place or to the nice playground that's a bit more far away than the small one around the corner. everything is fine with that trailer, though i always have some kind of insecure feelings:
- the trailer is quite low and altough it has a small flag attached to a stick that should make it more visible i think it can easily be overseen by cars on the street .
- sitting in that trailer the kid is around 1 meter behind me so i don't see what he's doing or how he's doing unless i turn around. not a good idea while riding.
visiting copenhagen in december 2008 i saw lots of cargo bikes there used for transporting kids so i decided to get me one. a quick look around convinced me that buying one is no option for me (much too expensive) so i wanted to build one. since this is the first bike i built i had to go through some trial-and-error situations, but in the end all came out well. after some research on the internet i decided to build a bike similar to the christiania bike. this is how i did it:
- the trailer is quite low and altough it has a small flag attached to a stick that should make it more visible i think it can easily be overseen by cars on the street .
- sitting in that trailer the kid is around 1 meter behind me so i don't see what he's doing or how he's doing unless i turn around. not a good idea while riding.
visiting copenhagen in december 2008 i saw lots of cargo bikes there used for transporting kids so i decided to get me one. a quick look around convinced me that buying one is no option for me (much too expensive) so i wanted to build one. since this is the first bike i built i had to go through some trial-and-error situations, but in the end all came out well. after some research on the internet i decided to build a bike similar to the christiania bike. this is how i did it:
Step 1: Recycling an old bike
i got myself an old crappy bike and cut it in two halves along the black line.
Step 2: Frame construction
the next thing was to construct the front frame. i thought that bigger would be better so it became 100 by 100 cm. this was not a good idea, but more about this later. what you see in the pic is the frame made of steel tubes (welded) and the rear part of the old bike.
Step 3: Wheels
the idea now was to mount the front wheels directly to the frame (see detail). looking at pics of original christiania bikes i saw that they put the wheel axis not in the middle but a bit more to the front of the frame. also i wanted to have a handlebar that can be adjusted in height, thus only two short steel tubes were welded to the back of the frame where i wanted to put the handlebar in.
EDIT: the wheel axis at christiania bikes is moved a bit to the front but still behind the pivot. mine was in front of the pivot... i changed it after riding the bike for a few months and now steering is much easier :-)
EDIT: the wheel axis at christiania bikes is moved a bit to the front but still behind the pivot. mine was in front of the pivot... i changed it after riding the bike for a few months and now steering is much easier :-)
Step 5: Rear part
now to the rear part of the cargobike. i took the handlebar's pivot from the old bike, welded it to a steel tube and then welded the steel tube to the rear part of the bike. the angle you see in the pic between the steel tube and the pivot was again something i saw on a pic. this was the second bad idea to do - more about it later.
EDIT: after using my trike for some time with NO angle and some discussions later (see comments below) i must say it would be better to have an angle between the steel tube and the pivot. measured at a christiania bike it should be 9.5 degrees in the direction you see in the pic - which is the opposite direction of the standard castor angle on a bike.
EDIT: after using my trike for some time with NO angle and some discussions later (see comments below) i must say it would be better to have an angle between the steel tube and the pivot. measured at a christiania bike it should be 9.5 degrees in the direction you see in the pic - which is the opposite direction of the standard castor angle on a bike.
Step 6: Connecting parts
the inner tube of the handlebar's pivot gets welded to the front frame and then i did a ...
Step 8: Making it stronger
the rear part undoubtedly had to be stronger. so i added a second steel tube and a bracing.
Step 10: Brakes
for the brakes (old ones from another bike) i screwed two steel plates with holes to the frame.
Step 11: Test assembly 3
test assembly 3: looked good. but as i tried to ride it i recognized i was nearly unable to turn the bike in any whatsoever direction. after some research i discovered that the angle of the pivot might be the problem. also i read that any pedal-driven vehicle above 80 cm in width has to be checked by the authorities here. since i wanted to avoid this i had to make it smaller.
Step 12: S**t...
cutting the front frame, making it smaller and building a new pivot (taken from another old bike) were the next things to do.
Step 13: Frame
finally the frame was done. what followed was to mount the brake cables and all the usual stuff to the bike. one issue that had to be solved was how to operate the two front brakes with one handle. talking to a friend he came up with a nice solution: (see next step)
EDIT: two more improvements were necessary after some time
1) mount some cross beams between the handlebar and the front frame (see pic 2 in this step) and
2) mount some more cross beams on the lower end of the pivot to stabilize it further (see pic 3+4 in this step)
EDIT: two more improvements were necessary after some time
1) mount some cross beams between the handlebar and the front frame (see pic 2 in this step) and
2) mount some more cross beams on the lower end of the pivot to stabilize it further (see pic 3+4 in this step)
Step 14: Adaptor for the brakes
this adaptor delivers the power of one handle to two brakes simultaneously. and last but not least one needs a ...
Step 15: Final assembly
box to transport kids and things with the bike. that's it :-)
further improvements will be some cat eyes and other security stuff.
further improvements will be some cat eyes and other security stuff.
Step 16: Edit: adjustable steering damper
after improving a few things (see the edits in some of the steps above) the last thing to do to complete this battleship was to add an adjustable steering damper. since these things can be quite expensive i built my own with a spring and a turnbuckle. works fine :-)
Step 17: Edit: final considerations
the measurements in this pic are the actual ones of my bike. if i would build one like this again i would change some things:
1) don't make the handle bar straight. it should be bent like in the drawing. this will save some space and allows to sit more straight.
2) use 20'' wheels for the front. this lowers the center of gravity and improves the handling on sloping grounds. the problem that arises is that you can't use the simple pivot i used - there's not enough room left between the ground and the box. a solution would be to
3) use conical roller bearings (these are parts used in cars) instead of the pivot .
4) don't build that double-break-thing for the front wheels yourself. you can purchase a better thing known as "double barrel brake lever" quite cheap which allows for independent adjustment of the two brakes.
5) adopt the size of the box to your needs. for me it's fine - i need to transport two kids and stuff at the same time (some times there are 4 kids and their things in the box...). if you don't need that much space make it smaller! because even the slightest wind is a burden if you have to pedal against it... one way to go would be to build a box from cardboard and to refine it until you think it's good. then build it from wood.
6) a camber of wheels improves the handling even more.
7) before building the frame watch some of these videos, this will help a lot: http://www.youtube.com/results?search_query=Bicycle+Frame+Building&aq=f
if you ever build a bike like this or get infected by the cargo-bike-virus and build some other construction please let us all know. post a pic or a link in the comments-section!
1) don't make the handle bar straight. it should be bent like in the drawing. this will save some space and allows to sit more straight.
2) use 20'' wheels for the front. this lowers the center of gravity and improves the handling on sloping grounds. the problem that arises is that you can't use the simple pivot i used - there's not enough room left between the ground and the box. a solution would be to
3) use conical roller bearings (these are parts used in cars) instead of the pivot .
4) don't build that double-break-thing for the front wheels yourself. you can purchase a better thing known as "double barrel brake lever" quite cheap which allows for independent adjustment of the two brakes.
5) adopt the size of the box to your needs. for me it's fine - i need to transport two kids and stuff at the same time (some times there are 4 kids and their things in the box...). if you don't need that much space make it smaller! because even the slightest wind is a burden if you have to pedal against it... one way to go would be to build a box from cardboard and to refine it until you think it's good. then build it from wood.
6) a camber of wheels improves the handling even more.
7) before building the frame watch some of these videos, this will help a lot: http://www.youtube.com/results?search_query=Bicycle+Frame+Building&aq=f
if you ever build a bike like this or get infected by the cargo-bike-virus and build some other construction please let us all know. post a pic or a link in the comments-section!
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I am realizing that I am going to have to use tapered (conical) bearings rather than the steering fork due to the lower ground clearance. I understand that Christiania uses tapered bearings as well.
There are not a lot of instructions online how to set up a shaft and tapered bearings for a cargo bike, but there is one here at 2:20-3:44 that might be useful for some.
http://www.youtube.com/watch?v=XSOTP1xj36Y
carkat, is this the way you envisioned the conical bearings working?
As always, thanks!!
yeah, this would be the pro-approach. i was thinking of using bearings including pre-made housings and somehow attaching them to the frame so there's no lathe needed. examples are here , here and here (e.g. hub II).
another approach would be to adjust the clearance so you can use the bicycle head tube like this guy did here
dotan
but be sure to run the cables from the handlebar downwards in the middle of the back of the box, so that if you turn the box the cables don't get in your way.
Sorry for all the questions, but I am curious about the second (lower) long steel tube in Step 8. It looks like it has a nice bend in it, and I am curious as to how you did that. Did you measure the radius of the bend and use a tube bender, or did you bend it in some other ingenious fashion? I can't thank you enough for your work!
the bending was really low-tech. i filled the tube with sand, closed the ends with tape and bent it over a small piece of tube with a bigger diameter i had lying around.
in the meantime i built myself something similar to this: http://youtu.be/PqZoEd8iNjk which is a good investment if you are going to bend tubes more often than once in a lifetime.
i didn't make any mods since the last one mentioned in the i'ble. but be careful: if you take building this bike seriously it could happen you won't be able to stop building cargo bikes. they are always open to mods and improvements - an endless source of inspirational tinkering :-)
1. What did you use to create the forks for the wheels on either side of the box? Was it something like 11 GA steel, and if so, what was the diameter of the holes and rectangles?
2. Did you use GMAW welding process, GTAW or something else?
Awesome work, this bike looks great!!
2. GMAW. but if you're able to do GTAW welding i'd recommend it. looks much better and the stability is the same.
What about eliminating the head stock pivot all-together and replacing it with a lazy susan ball bearing plate? You could then drop the bottom of the box down another 5 to 6 inches thereby lowering center of gravity for loads that much more? You could use one larger tube going underneath the box or two tubes parallel to each other, welded to the outward edges of lazy susan plate. They would have to come together before mating to the crank area so pedals & feet don't hit.
thanks a lot for all your thoughts! hope i can build one or the other idea when i have time again to do some improvements or a new bike :-)
thank you! since i didn't test any other head stock angle the only thing i can say is that a straight angle works well. you just have to get used to lean into curves when riding but that's all. the angles mentined in the instructable are there because i thought that christiania is building this kind of bike for quite some time now and they probably know what they're doing. . .
also have a look at the last comment from sillywilly with the reworked pic of the trike, he's making a good point there.
good luck!
I just posted looking for DIY plans for a front load tadpole tricycle. Your trike looks like what I am looking for however I need plans for a, "Complete Idiot", I am new to this and not very technically proficient.
Do you know of any companies that sell plans? I can find plans for trikes, bike cars, etc but not front load tricycles. The prices from companies that make the trikes is just o high. Besides I think I would like to learn how to do this.
Any help or directions would help.
Your plans seem clear by the way but as I said I am not very technical and some of the discussions go over my head. Sad but true.
on the other side, as i started to build this trike i didn't have any mechanical knowledge at all and my experience in metalworking was very limited. building such a trike is a great opportunity to learn, though it takes time. and it can become much more: based on my experience with building cargo bikes i got a side-job as mechanic with a cargo bike dealer last week :-)
if you are going to build one and need help just let me know! good luck!
I will most likely be asking you a lot of questions if I decide to go forward. I have looked at the ones you can buy and you might as well be buying a used car.
Thanks for the link I will chec it out.
I need to do this even if it is just for the exercise.
My kids will appreciate all your hard work.