8
N[4LII1O P E DI A
recumbents
VOSS SPEZIAL-RAD GMBH
W
EVO represents the happy conjunction of the skills of Klaus Beck and Hans Voss. Klaus Beck teaches art and physics in a comprehensive school in Hamburg where he encouraged students to build bicycles without being bunkered by preconceptions. Hans Voss is a respected distributor who has sold a dozen different makes of recumbent, many from abroad. This has given him a clear idea of the various design factors which hold many people back from buying a recumbent. Hans found that some people disliked machines with long runs of chain. Others were nervous of the seating position or handling characteristics of some models, or were dissatisfied with the wheelbase. So he got to work with Klaus Beck, who had already made more than twenty different experimental machines. The result of their co-operation, the BEVO-Bike, incorporates a pragmatic set of aims: to provide the best combination of comfort, aerodynamic position and safety.
Comfort is addressed in both the physical and perceptual sense by the unusual scat, which has variable positioning not only for the back (from near upright to laid-back) but also for the leather cutaway base. The seating position is higher than usual on recumbents, giving better visibility in traffic, and the direct steering is above the bars, which feels reassuring and natural to many riders. The EasyRider position seems to enchant the general public more than under-bar suspension. The handlebar is easily adjusted for position, and a longer or shorter stem can be fitted. Almost any newcomer to recumbents can master the BEVO-bike within a few minutes. Its wheelbase is only a tiny bit longer than that
of a Dutch roadster, and the bottom bracket is sited at a moderate 10cm below seat-level. This feels comfortable, and yet keeps the forward transmission system within the neat aerodynamic profile (which also encompasses the handlebar and rider's arms). Once the rider's weight is on the BEVO-Bike the riding position becomes more recumbent than it appears in our photograph. A handsome Zzipper fairing, specially commissioned for the BEVO-Bike, further improves aerodynamics, and can be used in conjunction with a rain cover for the rider. A further important aid to comfort is the under-seat frame suspension, with a 100mm travel to take out serious bumps. The front-wheel drive system, patented as Top Drive, avoids the problems associated with a long chain to the rear wheel. The twisting force is applied to the chain only when the wheel is turned severely, which is not the case in normal use. In any case a restrictor system limits the turning circle, in order to avoid excessive stresses on the chain. Once you get above a certain speed there is very little lateral movement in the front wheel. We did not find the restricted turning circle to be a big problem in practice. A roller close to the chainwheel keeps the chain in tension. This may need to be checked occasionally and adjusted, otherwise the chain could jump off the sprocket. Front-wheel drive also allows better storage, since the triangle can be folded under the frame. At the same time, the seat can be folded down. In line with their aim to make the BEVO as userfriendly as possible, the makers have chosen Sachs hub gears: the Super 7 gives a welcome 284% range from top to bottom. Only hub gears are possible with the BEVO-Bike. Luggage can be carried either behind the seat, or in an unusual under-frame holder. There will soon be under-frame low-rider racks available, and a clip-on Karrimor rucksack/bike bag for behind the seat. Despite the emphasis on easy riding, Hans and Klaus do not intend the BEVO as simply a recumbent for beginners. They want it to be seen rather as a recumbent equivalent of the Moulton APB: a recumbent All-Purpose Bicycle: a comfortable, effective and enjoyable vehicle for almost every cycling need.
Klaus Beck and Hans Voss
The front-wheel drive solves many problems