Why Recycled Plastic Bikes Aren't (Yet) Practical
We frequently expound on why bikes are an energy-friendly and clean form of city transportation, yet rarely get to report on innovations that take leaps in making bicycle production more sustainable and energy-efficient. That's why the Frii injection-molded recycled-plastic bicycle is so enticing. Looking a little like a grown-up's version of a brightly-colored Big Wheel, it sports snap together pieces and a lightweight, city-friendly design. Plus, the Frii bike, created by Israeli Dror Peleg, could be locally made anywhere. There's a big bummer drawback to this and other plastic-parts bicycles, however.
Photo of Volvo's Itera bicycle courtesy Wikimedia.
Remember how your Big Wheel broke down over time? Usually a pedal would be first to crack, followed by the frame itself. This wasn't necessarily just due to hard riding - exposure to UV sunlight faded and degraded your wheel's plastic parts. In a few short years, your Big Wheel likely ended up on the junk heap, and you instead got an aluminum or steel-framed bicycle.
That same degradation process would be a risk for a recycled-plastic bicycle. Peleg told Gizmag that his Frii bicycle would use plastic-injection molds for its diamond frame that are similar in size to plastic chair molds - stability and stiffness are reinforced, he explained, with a pyramid-like construction of "ribs."
Peleg also noted that the Frii is designed for city streets, and might not need the stiffness of a road bike. However, Peleg admitted his design process, though it allowed him to build a life-size prototype, might still require some engineering to be ready for manufacturing primetime.
And that's where the experience of two other failed plastic bicycle manufacturing attempts comes into place.
Back in the 1970's Volvo had an idea for a flat-pack, user-assembled plastic bicycle called the Itera. Injection-molded plastic composite parts were used, and as Wikipedia notes, the bike, while heralded at first by the media, was a "technical and commercial failure" when it was introduced in the early '80s.
In order to have adequate stiffness, Itera was as heavy as steel bikes, yet its flexibility made users initially wary of their own safety.
"Plastic alone is just not stiff enough," says bike builder Ken Wheeler of Renovo. "A plastic bike would have to be reinforced, like fiberglass, for example. Once it's hard, it's inert, and not really recyclable."
Fiberglass was what Benjamin Bowden used in his "Bowden Spacelander" bicycle, made for a short time in the '60s. Bowden's organically rounded shapes were definitely futuristic, and are prized by collectors (they were reissued in the 1990's), but they didn't have time to find widespread favor with the public before the Bowden company went bankrupt.
So the quest is still on to find a plastic bicycle that is stiff enough, uses recycled materials (wouldn't it be nice to do something bike-like with Pacific Gyre waste?), and can still be recycled. In addition, it's design must be revolutionary enough to catch the eyes of the tech-smart, yet conventional enough to get mainstream acceptance.
In short, we need a green-minded Steve Jobs of recycle-plastic bicycle design.