Recumbent bicycles may offer a more comfortable riding position, but they typically also have pretty long chains. After all, power has to be transmitted from the pedals at the front to the drive wheel at the back. Norway-based inventor Marc Le Borgne, however, has created an alternative. His KerVelo recumbent has an 18-speed gearhub transmission built into the front wheel.
The KerVelo utilizes an existing Pinion sealed gearbox transmission. Although these are designed to be housed within the bottom bracket on upright bikes, Marc has put his in a custom aluminum shell that doubles as the front hub. It's sort of like a penny farthing, although because it's a multi-gear system, no huge front wheel is required in order to gain momentum – the pedals don't necessarily turn at the same rate as the wheel.
According to Le Borgne, the design offers a seating position that combines the comfort of a fully-recumbent bike with the visibility of an upright. And, of course, there's no long, greasy chain getting riders dirty, requiring maintenance, or decreasing pedalling efficiency once it starts to stretch out.
Needless to say, the big question is whether or not the front tire will rub against riders' legs in the turns. Marc tells us that at higher speeds, the turning radius will be wide enough that it won't be an issue. At lower speeds, he says, riders can just move their legs out of the way. It's probably something you'd have to try out first-hand to know for sure.
Le Borgne has already built two prototypes, and is also interested in applying the design to a tricycle. He's currently looking for commercial partners to manufacture the KerVelo. That name, by the way, is apparently derived from the Breton-language "ker" (house) and French "velo" (bicycle), as in "the best house to engineer the best bicycle" – although the Cervelo bicycle company would likely have something to say about that.
The more recent of the two prototypes can be seen in action, in the video below.
Source: KerVelo
