A little "wow" is a must, and with this bike, the path is short: the unusual proportions give laymen pause, and urban bike connoisseurs sink into the technical details. The ThinBike was presented at the penultimate Eurobike, and Schindelhauer is launching this 25-piece special series with very special everyday equipment for the 2015 Berlin Bike Show: Dynamo continuous light, the in-house seat post light, mudguards and a front carrier for little more than a briefcase characterise our pin-up. The visual characteristics of the bike are so convincing that it has won two design awards. The basic idea of creating a compact, easily portable bike with a parking width of less than 20 centimetres also undoubtedly meets the urban zeitgeist and the spatial requirements of small flats. It also passed the carrying test from the cellar to the test track with flying colours. The seating position of the one-size-fits-all frame is a little short at 1.80 metres, but still okay, and off we go.
Just as the legs reach the lower limit of the usual travelling speed, the automatic gear shifting system slams in the long gear ratio. It takes some getting used to, but it's still better than a singlespeed. Yes, the ThinBike runs decently, and the 24 mm tyres are also a good idea in terms of riding dynamics. Back to the start, the saddle height is still not right. The second handbrake was sacrificed for the sake of a clear line, but the coaster brake is easy to modulate and the bike stops precisely in front of the workshop with it and the mechanical disc brake.
Before setting off again, a quick check of the twisty stem: Oops, it wasn't very tight! Loosen the quick-release, readjust and tighten with all your might. Now it holds. But you don't want to operate it several times a day.
SRAM Automatix
The ThinBike has a two-speed hub gear system from Sram, but there is no gear lever: gear changes are automatic. Unlike the former "folding bike gearstick" Duomatic, which changed the gear ratio by backpedalling, the Automatix has a pre-set shift point. The Automatix uses a centrifugal clutch to shift gears at a specific riding speed. The major disadvantage of the system is that the centrifugal clutch cannot be customised to personal requirements; the shifting point is only dependent on the wheel size. According to the manufacturer, this happens at 15 kilometres per hour with 20-inch wheels, at around 18 kilometres per hour with the test bike and only at 21 kilometres per hour with 28-inch wheels.
The gear ratio jump between the two gears is about a third. This means that if you are pedalling at 60 crank revolutions when you change gear, you will only be pedalling at around 40 revolutions in high gear - a big difference that takes some getting used to. Once you are in high gear, the hub does not shift back under load when you slow down. This means you have to interrupt pedalling briefly. This is a nuisance when going uphill.
Our opinion: an interesting principle. However, the speed at which the gear changes should be adjustable. And the direct gear should be engaged at cruising speed in favour of smoother running, not when starting off. The starting gear is the low-loss direct transmission without gearbox. The cogs of the planetary gearbox only start to rotate at higher cruising speeds, which reduces efficiency somewhat.
