Urban bike in the test: Additive manufacturing with the 3D printer is on everyone's lips and is changing more and more from rapid prototyping to series production. No wonder that the bicycle industry has also recognized this. Small parts are already increasingly coming out of the printer, but an entire bicycle? With the Stadtfuchs, Urwahn Bikes has managed to create a complete frame in a 3D printer in a long tinkering and engineering process. But how does the "monocoque" made of steel and iron drive?
Due to the way of production, the construction can be extremely material-optimized. Despite its steel heart, the entire bike weighs just under 12 kilograms in size M (without attachments such as mudguards and luggage rack), top values for steel and this equipment.
Urban fox primal craze: technical highlights
The urban bike is also a feast for the eyes from a technical point of view. The factors of function and design were equally taken into account in the design and equipment selection.
The power is not transmitted conventionally with a chain, but by means of a belt drive made of carbon. The Gates carbon toothed belt system CDX is not only extremely low-maintenance, but also incredibly efficient and quiet. The ideal component for commuters and city bikers whose bikes have to work and aren't constantly hanging on the assembly stand.
The Shimano Alfine wheel hub gear with a total of eleven switching stages offers sufficient bandwidth in city traffic. This means that climbs can be mastered comfortably and it also provides enough propulsion to swim with the traffic. Switching is also very quick and easy using the trigger on the handlebars. The only thing is that changing to an easier gear requires a little more thumb strength under load.
As soon as there is propulsion, the fully integrated lighting elements, which are operated by a hub dynamo on the front wheel, also switch on. Despite the additional power taker, the resistance is not noticeable. The front wheel runs very smoothly and quickly.
Ergon components ensure the necessary comfort, even if you sit in the saddle for a long time. With the SFC 30 Evo Gel saddle of the Stealth Edition, the buttocks are sufficiently padded and are perfectly complemented by the GA30 grips. The ergonomic shape of the handle prevents numb hands.
Urban fox primal madness: Additive manufacturing makes it possible
A highlight is definitely the internal cable routing in combination with the additive manufacturing technology. Because the steel structure is built up layer by layer with the 3D printer, the ducts for the line can also be printed in at the same time. This prevents the annoying rattling of internally routed cables right from the start.
Due to the production in the 3D printer, the main frame looks like it is made of one piece, but it is a combination of tubes and connecting elements that are brazed together. In order to still be able to thread the belt drive into the frame triangle, the frame was interrupted above the hub mount. After installing the Gates carbon belt, a connecting bar holds the elements together. It is also possible to change the belt at any time.
Urban fox primal delusion: Driving impression
Thanks to the special frame shape and the steel construction, an enormously high level of comfort can be achieved for a "damper and springless" system, so it is comfortable and well prepared for the bumps in road traffic.
During the extensive test drive, what the first impression of the frame shape suggested was confirmed. Due to the missing connection between the seat tube and the bottom bracket, the rear end is flexibly suspended. With enough flex, the material also contributes positively to cushioning without losing consistency and stability. As a result, the Urwahn Stadtfuchs easily copes with small bumps and cobblestones.
Thanks to the sporty yet upright seating position, it is possible to move quickly and comfortably. So there were no signs of fatigue on the entire body during our test kilometers. For our test we had the size L with a height of approx. 180cm. Since the Urwahn Stadtfuchs is available in a total of 5 different sizes from XS to XL, there is something for every body size and every type.
Urban fox primal delusion: Geometry
Geometry primal madness city fox
| XS | S | M | L | XL | |
|---|---|---|---|---|---|
| seat tube (in mm) | 520 | 535 | 550 | 565 | 580 |
| Top tube horizontal (in mm) | 520 | 540 | 560 | 580 | 600 |
| head tube (in mm) | 135 | 150 | 165 | 180 | 195 |
| chainstay (in mm) | 405 | 405 | 405 | 405 | 405 |
| Wheelbase (in mm) | 956 | 976 | 996 | 1016 | 1036 |
| Steering angle (in °) | 73 | 73 | 73 | 73 | 73 |
| Seat angle (in °) | 73 | 73 | 73 | 73 | 73 |
Urwahn Stadtfuchs: availability and accessories
A little extra equipment was already installed on our test bike. The mudguard system and the luggage rack are available in the Urwahn shop for €64,95 and €49,95 respectively.
The wheel itself can also be configured individually. The color can be selected from five different standard colors according to personal preferences. If that's not enough, you can also choose the frame nickel-plated or copper-plated or even request an individual color or a special finish. In addition, high-tech can also be ordered or configured. With the optional GPS tracker, the city fox can always be found if it is stolen.
All further details and the shop can be found at: www.urwahnbikes.com
