We found it quite impossible to build the first series in 7020 aluminium for several reasons and finally decided on using laser-cut steel (CrMo and seamless precision tube) instead. The weight of the steel frame is almost exactly the same and it should be more comfortable to ride.
The same goes for the front wheel. The discs are pressed from (thinner!) steel now using the same tools, bolted and glued together and finally filled with a structural foam. This made the front wheel stronger but heavier. We are currently working on an alternative that should be much lighter.
The boxes consist of ultralightweight DuFLEX Balsa Core pannels from which the 3 parts are CNC-cut. and bonded with a high density epoxy adhesive mixture.