Christiania Bike conversion

[Arvicola Terrestris]

I often gets question about my conversion of my Christiania Bike (cargo trike) into an center motor e-bike. So I've decided to dedicate a thread to Christiania Bike conversions. NOT ONLY MY BIKE, YOURS TOO.

Why Christiania Bike in particular? Because there is a rather large community loving these bike, which until recently all has been built in the Free town of Christiania, Copenhagen, Denmark, a comunity with 2000 souls. A place for Hippies, Cannabis and car-free culture and it's still like that, I visit the place once a week :wink:

 

[Arvicola Terrestris]

I got these questions in a PM:

Here are some questions that I have:
1: I gather you had to bend the frame. Is that true of all Christianias, or only certain models?
2: Is there insufficient clearance to mount underneath the frame?
3: How does one go about bending the frame?
4: Are there less intrusive options that you have heard of?
5: Any other modifications that would also be necessary in order to complete the conversion?

My conversion is with a Bafang BBS02 750w 48v.

1: If you will fit the Bafang BBS02 to an Christiania Bike I only know of one model and that is the one with the large single frame tube. There are older model with double frame tubes which can't be used. Also it has to be the steel model, not aluminium, because you need to weld.

2: yes, see picture number two

3: Most people would need help from a blacksmith, and it will only take him one hour to make this operation.
But if you do it yourself the use a hammer and blow torch to make the dent.

 

[Arvicola Terrestris]

Here are some questions that I have:
1: I gather you had to bend the frame. Is that true of all Christianias, or only certain models?
2: Is there insufficient clearance to mount underneath the frame?
3: How does one go about bending the frame?
4: Are there less intrusive options that you have heard of?
5: Any other modifications that would also be necessary in order to complete the conversion?

4: Not on the Christiania cargo trike model, but they make a two wheel model which I'm sure you can mount a center motor without the need of welding and other very hot techniques.

5: Depending on the the power of your motor, you could upgrade the front brakes to hydraulics, it makes a big difference when going 35km/h. It is also a good idea to place the battery in the front of the cargo box it stabilizes the bike, you can test it with a kid, first in the back of the cargo box and then in the front = big differers in handling. A mirror is also nice to have.

 

[Samd]

I suggest a smaller chainring to take the torque off the motor. Your clutch and controller will love you for it in the long term.

 

[Arvicola Terrestris]

I suggest a smaller chainring to take the torque off the motor. Your clutch and controller will love you for it in the long term.

Depends on how big the rear chainring is :wink:

The gear ratio is 2.1:1, which is right in the blink, T46 in front and T22 at the rear. I have a NuVinci in the rear wheel and they specify a maximum gearing of 2:1.
The Nuvinci Autoshifter is set at approx. 75 rpm (pedal arm).
Highest motor eff. is at 85 rpm (pedal arm) and
highest motor torque is at 65 rpm (pedal arm).

 

[whollycow]

No concerns over the structural integrity of the bike after modifying the frame like that?

 

[Arvicola Terrestris]

No concerns over the structural integrity of the bike after modifying the frame like that?

No

The mechanic properties of the cross member is the same after the modification, only concern is the strength of the welds, because its difficult to weld galvanized steel (galvanized inside also).

The modification to the large frame tube, the dent, is in a place were the stress is not so large. In an effort to explain were the critical forces are applied to the frame, I have made a very simple schematic static calculation of the frame. (VERY SIMPLE)



The area from G to H (GH) is were the dent is, the load in this area is aprox. 60-70% of the load on the saddle. (which can be 3x larger then your own weight when you hit a pot hole). The saddle is at point J, the rear wheel at I. The large frame tube is simulated as an beam A-D-H-E.

I'm not saying that load in this area is negligible, but it is not the most stressed part of the frame. And remember that we aren't removing anything from the frame, just relocate it with a very large hammer

If the frame should start to break up because of material fatigue, then steel is breaking slowly, while aluminium snaps.

 

[whollycow]

Did you have the NuVinci on the bike by the time the motor was installed? I have the 7 gear IGH (Schimano? Can't recall at the moment). I know the motor can present difficulties with shifting, but I suspect with a motor on it we won't need to shift as often. We mostly need the motor for the couple of hills standing between us and civilization. We don't expect to ride it too hard.

 

[Arvicola Terrestris]

Did you have the NuVinci on the bike by the time the motor was installed? I have the 7 gear IGH (Schimano? Can't recall at the moment). I know the motor can present difficulties with shifting, but I suspect with a motor on it we won't need to shift as often. We mostly need the motor for the couple of hills standing between us and civilization. We don't expect to ride it too hard.

The NuVinci was part of the conversion I did. Before the bike had a Sram hub system with integrated 5 gear IGH. The NuVinci is a major upgrade. You won't need more then 5 gears. Depending on what motor wattage you choose, but with a 750 watt motor there is no hill that will stop you.

 

[Arvicola Terrestris]

I thought about writing about the Christiania bike in more general terms, and then found this excellent English written history on the homepage of the Christiania Bikes company

So here it is, from the companys mouth:

The first Christiania Bikes 1984

Christiania is an area in Copenhagen which used to host the Navy. When the military moved out, the barracks were left empty for years; in 1971 young people moved in. The I/S Christiania Smedie (=Smithy) was founded in 1978. Christiania chose from the beginning to be a car-free area. This motivated its inhabitants to think of other means of transport. At first robust bicycle trailers were developed by originally using old bed frames. Later these bicycle trailers were improved and sold all over Denmark. In 1984, the first cargobike was launched. Its ground-breaking feature was that family cycling, including children transport, was made available in a practical and safe way. Children transport has been maintained over the years as the core function of the Christiania Bikes tricycles.

Soon, people outside Christiania noticed the manoeuvrable, sturdy and environmentally friendly cargobikes and in 1990 the Christiania Smedie moved to the island of Bornholm to concentrate on production of tricycles. Our goal was to offer a convenient replacement to the car, and eventually the idea of family tricycle would become a normal means of transportation all over Denmark. Indeed nowadays the family tricycle has become a popular means of transport all over Denmark and in many countries across the world as well.

In Bornholm, we continually refine our products. In 1994, the company was renamed “Christiania Bikes“, and our products bear this world-famous trademark.

Information and picture taken from:
http://www.christianiabikes.com/en/

 

[whollycow]

So I had been assuming all this time that my frame is steel. I just checked and it is actually aluminum (or at least a magnet didn't stick to it). I'm guessing that means no possibility for making the kinds of modifications we're talking about. Any ideas?

 

[Arvicola Terrestris]

So I had been assuming all this time that my frame is steel. I just checked and it is actually aluminum (or at least a magnet didn't stick to it). I'm guessing that means no possibility for making the kinds of modifications we're talking about. Any ideas?

I won't recommend doing this Bafang BBSxx conversion if your frame is aluminium.

The most straight forward conversion would then be to lace a hub motor into your 24" rear wheel. 500watt should be great and 1000watt awesome.

A conversion with two hub motors in the front wheels has been done, and working well (with regen!), but it's much more complicated.

So go for a rear wheel direct drive hub with regen. at approx 750w.

 

[whollycow]

The most straight forward conversion would then be to lace a hub motor into your 24" rear wheel. 500watt should be great and 1000watt awesome.

Looks like this is my best option. I was hoping I could keep my IGH but I guess I'll have to make a sacrifice...
Thanks for the help anyway!

 

[Dumsterdave]

I know this thread is quite old, but I also have the aluminium frame christiania. I wanted to do the bafang mid drive, but i guess it may not be a good idea... My bike currently has an internal geared hub and there is no place to mount an external rear derailer. Ive looked at the christiania bikes that are electric and they all seem to have a different model of dropouts that allows for a derailer to be mounted. What are my options here?

 

[Dumsterdave]

ive found this... https://boxbike.dk/da/elcykel-kit/162-elcykel-kit-christiania-ladcykel.html
so i know there are mid drives that will fit into that space, but i dont know who makes this kit. Also, i would like to get a bit more powerful motor than the 250/350 36v that they sell

what about the cyclone or mini cyclone that lunacycle sells? Has anyone had any experience mounting these?

 

[183sunman]

I know this thread is quite old, but I also have the aluminium frame christiania. I wanted to do the bafang mid drive, but i guess it may not be a good idea... My bike currently has an internal geared hub and there is no place to mount an external rear derailer. Ive looked at the christiania bikes that are electric and they all seem to have a different model of dropouts that allows for a derailer to be mounted. What are my options here?

Hi i make already some conversion Christiania bike , and also in Copenhagen. For you back drop outs (internal gears oryginal) ou can easy use external , also back disc break.

For this you need 1) adapter disc breaks for "not hydraulic-frame" , and 2) Adapter External gears

Zdjęcia

Zdjęcia

 

[pnissen84]

I know this thread is quite old.

I did a conversion of an aluminium Christiania bike with the kit from boxbike above (BEWO 36v 350w). I’ve done over 2.000 happy km on the bike, but now the bearings inside the mid drive hub is roasted.
It seems like the bbs02 hub is more reliable, but seems impossible to fit on my bike. I’m therefore looking for alternatives, like the back wheel drive. But don’t know what to go for, dimensions etc.?

Or is there any alternatives on the market I 2019 with a smaller mid drive, that will fit in the fram of a Christiania bike Alu?

 

[Chalo]

It seems like the bbs02 hub is more reliable, but seems impossible to fit on my bike.

Why do you think that?

 

[Dumsterdave]

I know this thread is quite old.

I did a conversion of an aluminium Christiania bike with the kit from boxbike above (BEWO 36v 350w). I’ve done over 2.000 happy km on the bike, but now the bearings inside the mid drive hub is roasted.
It seems like the bbs02 hub is more reliable, but seems impossible to fit on my bike. I’m therefore looking for alternatives, like the back wheel drive. But don’t know what to go for, dimensions etc.?

Or is there any alternatives on the market I 2019 with a smaller mid drive, that will fit in the fram of a Christiania bike Alu?

I actually ended up getting a bewo from a UK source that was about half the price of boxbike. It's at 4500km and still running strong. Not the most powerful motor, but it does the job

 

[mikeydog4]

Just bought a used Christiania bike here in California and wondering if there are any mid-drive options in the US. I cannot find Pendix or any of the ones that seem to fit without having to modify the frame.

 

[amberwolf]

Is yours the same as the one pictured in the first post?

If so, you may also have to modify the frame a bit, depending on the specific middrive you use, to fit it in there.

Alternately you can use one that does not mount directly to the BB, but instead just drives one of the chainrings, like the Stokemonkey and similar drives. That usually means making a custom mounting bracket for your specific frame for whichever drive you want to use, to fit the drive near the BB either under, in front of, or behind that area of the frame.

 

[dogman dan]

I know diddly squat about mid drive installs, but couldn't you mount that mid drive kit under the frame instead of inside that triangle? Lowers the ground clearance some, but it should be possible I'd think.

Very neat installed inside the frame, but I'd avoid cutting and welding an aluminum frame. Steel frame I'd just cut the frame and make it stronger.

 

[JDaspry]

Anyone tried to fit a TSDZ2B or even TSDZ8 ?

 

[amberwolf]

Not that I could find, but there *is* a thread dedicated to your specific question

Tongsheng TSDZ2 For Christiania bike

Does anyone know if a Tongsheng TSDZ2 will fit on a Christiania bike, or can anyone give me a really detailed set of measurements? I see some on the product site but not enough to determine if I can use it of not.

endless-sphere.com

 

[JDaspry]

Oh, how did I miss that... Sorry for reviving the wrong thread. I did find a post on facebook from @nikolajbak , saying he managed to do it, removing the controller and grinding a good part of the motor casing. I‘ll ask him to post pictures in the tsdz2 thread, if he‘s willing.