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Credit where it's due
Here's our inspiration:
Constrution method: The N55 XYZ SPACEFRAME VEHICLE
N55 made the original aluminum XYZ SPACEFRAME VEHICLES and made their drawings open source. We've chosen to use this construction method because it's easy, and no welding is needed. We don't know how to weld yet, and we figure that lots of other people who might want a cargo bike don't either. Plus it provides the possibility to make instant changes and modifications. Other than that it's cheap, light and looks cool.
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| N55 XYZ SPACEFRAME VEHICLES - www.n55.dk |
Bike type: The Long John and the Bullitt
There's a long history of two-wheel cargo bikes in Denmark. Traditionally they were for some reason called John. The main types were the Short John and the Long John.
The Long John formula has recently been updated by the guys at Larry vs. Harry in the form of the Bullitt. It is an absolutely amazing bike, but comes at a price. The cheapest version costs $2.500,- delivery not included.
The steering mechanism: Center Hub Steering
You might consider the frame design of a two-wheeled cargo bike a simple question of carrying a load between two points, just like a simple beam. The two supporting points are the front and rear hubs. In that respect the existing bikes are not structurally optimal. This is because the frame has to reach up above the front wheel at a pretty steep angle in order to grab the front fork.
Structurally we'd rather avoid sending the loads at play in the structure up through these angles, as they are awkwardly steep and require very strong joints.
We'd like to just connect directly from the front to the rear hub. This could strengthen the structure, save weight and lower the center of gravity of the bike - making it more comfortable to ride and steer.
The thing is, you wouldn't be able to turn the front wheel, which would be a problem. The straight forward solution is to use the front fork, and end up with the situation shown above. There is however an alternative in the form of Center Hub Steering.
Apparently it hasn't been done on a bike before. Maybe it's been deemed too complicated, or maybe the standard front fork has always been chosen out of old habit. Whatever the reason, we'll give Hub Steering a go and see if we can make it simple enough to be viable. It'd be cool if we can pull it off.
Apart from the practical reasons, we're also doing it this way because we think it looks nice.
We'd like to just connect directly from the front to the rear hub. This could strengthen the structure, save weight and lower the center of gravity of the bike - making it more comfortable to ride and steer.
The thing is, you wouldn't be able to turn the front wheel, which would be a problem. The straight forward solution is to use the front fork, and end up with the situation shown above. There is however an alternative in the form of Center Hub Steering.
Apparently it hasn't been done on a bike before. Maybe it's been deemed too complicated, or maybe the standard front fork has always been chosen out of old habit. Whatever the reason, we'll give Hub Steering a go and see if we can make it simple enough to be viable. It'd be cool if we can pull it off.
Apart from the practical reasons, we're also doing it this way because we think it looks nice.
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We're not exactly breaking new ground with this mechanism. It's been done successfully before as early as 1921 on the Ner-A-Car. Below is the 1925 model.
You might say that we're being in-consequent by choosing Hub Steering, as it will probably make it more difficult to build the bike. You would of cause be right, but for us this is where much of the fun comes from, and if we succeed we might actually bring something new and useful to the world of cargo bikes.
If not, we already have designs for a regular front fork-version, which we plan to build as well.
The DIY spirit: Copenhagen Suborbitals
A lot of our inspiration for starting the project comes from Copenhagen Suborbitals. We don't know much about practical bike building, but we figure that if those guys can build a man-carrying space rocket using plate steel, pipes from the local hardware store and a hairdryer, we should be able to build a cargo bike.
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| Copenhagen Suborbitals doesn't have much to do with bikes, but here's their launch vehicle Sputnik with one of their rockets and a cargo bike. |
