One of the main goals for anyone designing a folding bike is to make the bike as compact as possible so it's easier to carry and store when not in use. Karstin Bettin from Hannover, Germany has ticked that box with his Kwiggle Bike. Bettin claims the Kwiggle Bike, which is the result of four years of development, is the most compact folding bike in the world.
The Kwiggle Bike, which Bettin is showing at Eurobike 2013, is an exercise in minimalism that makes use of a number of patented design elements that allow it to fold down to a compact package. Chief among these are a special hinge that enables the bike’s contortionist-like folding capabilities and the placement of the drive cog on the outside of the frame, which allows for greater folding capabilities by keeping the chain out of the way.
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Even though the Kwiggle does have a seat, this is more for leaning on than sitting on as the bike puts the rider in an upright position. The “wiggle” in Kwiggle comes from the side-to-side movement of the seat as the rider pedals, which Bettin claims provides a more comfortable ride than a rigid seat would. The bike can support riders weighing up to 100 kg (220 lb).
Despite the upright “seating” position, Bettin claims it is easy to get the bike up to speeds of 25 km/h (15.5 mph), with each revolution of the pedals translating to 4.5 m (14.7 ft) of development. That’s for the single-speed prototype Bettin has on show at Eurobike, but he is working on a model that would have two to six gears and produce 7.5 m (24 ft) of development for each pedal rotation.
The prototype on show at Eurobike rides on 8-inch wheels and folds down to a size of 50 x 40 x 25 cm (19.6 x 15.7 x 9.8 in), which makes it small enough to fit in hand luggage for carrying on a plane. Constructed from aluminum, Bettin also aims to get the weight down from the prototype’s 8 kg (17.6 lb) to 6 kg for the production model.
Bettin also has a model with larger 14-inch wheels in the works, which will fold down to a maximum size of 55 x 40 x 25 cm (21.6 x 15.7 x 9.8 in), although he is aiming to get it even smaller than this. Bettin points out that the production models will also have brakes, which is something the prototype lacked.
Bettin is hoping to release the Kwiggle Bike before the end of the year. Pricing details are still to be ironed out.
Source: Kwiggle BikeView gallery - 16 images