Bicycles

Sheet metal-framed Voiroo Zero mountain bike brings rivets to riding

The Voiroo Zero's aeronautically-inspired frame
The Voiroo Zero's aeronautically-inspired frame
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The Voiroo Zero's aeronautically-inspired frame
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The Voiroo Zero's aeronautically-inspired frame
Using a CNC (computer numerical control) system, the main components of the frame are first cut from sheets of aluminum
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Using a CNC (computer numerical control) system, the main components of the frame are first cut from sheets of aluminum
The resulting flat pieces of metal are subsequently folded and molded into the desired shape, then riveted and glued into place
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The resulting flat pieces of metal are subsequently folded and molded into the desired shape, then riveted and glued into place
TrixonLab plans to build the Zero to order, and will offer it as a frame only, or in one of two complete bike builds
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TrixonLab plans to build the Zero to order, and will offer it as a frame only, or in one of two complete bike builds

Italy's Albaviation is in the business of manufacturing small aircraft, along with parts for them. So, what happens when the company's TrixonLab division decides to build a hardtail mountain bike? Well, with its riveted sheet aluminum construction, the Zero's frame is pretty reminiscent of a retro airplane. According to its creators, however, there's more to the design than just unique looks.

The Zero is the first model in TrixonLab's planned Voiroo Bike line. Other models in development include road and urban bikes.

Using a CNC (computer numerical control) system, the main components of the frame are first cut from sheets of 0.6 to 0.8-mm aluminum – some smaller bits are made from thicker sheets. The resulting flat pieces of metal are subsequently folded and molded into the desired shapes, then riveted and glued into place.

The company's Giorgio Mannozzi told us that this design, commonly used in the aeronautical field, offers a good weight-to-rigidity ratio. "The box structure allows us to have a monocoque, a single structure without specific weaknesses," he said. "On an equal weight (tube structure vs. box structure), the box structure allows us to have a greater rigidity and especially robustness."

Additionally, there are no welds in the frame, which are a structurally weak point on traditional tube-based bikes.

Using a CNC (computer numerical control) system, the main components of the frame are first cut from sheets of aluminum
Using a CNC (computer numerical control) system, the main components of the frame are first cut from sheets of aluminum

TrixonLab plans to build the Zero to order, and will offer it as a frame only, or in one of two complete bike builds. The frame weighs 1.65 kg (3.6 lb), and will sell for €460 (about US$590) on its own. A full bike featuring a Shimano XT groupset, Rock Shox Recon Gold TK suspension fork and XT 27.5-inch wheels will go for €2,490 ($3,194), while a bike equipped with Shimano Deore, Rock Shox XC 30 TK fork and Mavic Crossride 27.5-inch wheels will set buyers back €1,690 ($2,168).

California-based Ronin Bicycle Works also makes bikes from sheet aluminum, although it recently didn't meet the funding goal in a Kickstarter campaign aimed at taking them into large-scale production.

Source: TrixonLab

7 comments
Dweezil Speedy
How does the seat post attach and adjust?
ChrisOz
This design is not at least a bit clever. 1. The diamond shape is the worst shape to use - to recreate tubes with sheet-metal is as stupid as making a bike out of carbon tubes. It is not taking advantage of the materials advantages. 2. Riveting yes - but minimise rivets by glueing the metal shapes together. There exists glue which is much stronger than all these rivets. I built a full suspension bike from alu sheet-metal in 1986 and drove it from Mexico to Peru. I never would favour this one over mine.
Bob Stuart
Weight is easy to measure, but wind resistance matters much more. Wouldn't airfoil shapes make more sense? Structurally, the chainstays could use more width. Philosophically, I think it is a waste to design rigid frames with separate pivots and springs to achieve suspension, rather than designing a shape that distorts the same way under load. Bikes work because knees can be pressed into service for suspension, but fat, comfortable tires are slow. As for the rivets, when aluminum adhesives first came in, they were proposed for the tail rotor on a Bell helicopter. It passed fatique testing, but the inspectors asked for some back-up rivets to be added, "just in case." When it was re-tested, they were found to create stress risers, reducing the lifespan by 95%.
jeffrey
It's funny that people think rivets are "retro" on aircraft. 99% of current aircraft use rivets. Bonding aluminum is still an iffy practice, thermal induced expansion of metal, especially aluminum, can cause the bonds to deteriorate. I'd trust the reliability of rivets over glue any day.
Grunchy
I think airstream trailers are still riveted and not glued. The seams are sealed with some kind of mastic though. Rivets create drag, slightly.
frogola
just weld the damn thing.
JimMoore
I like the Jayhawk riveted frame better, but then I invented it