Generations of cyclists have struggled to train the famous "round pedal stroke" as perfectly as possible. This is the only way to achieve fluid efficiency from the biomechanically unfriendly circular path of conventional bicycle cranks. According to the laws of leverage, longer cranks would convert more power, but the pedals would quickly touch the ground in the lowest position.
A small team of dedicated engineers from Thuringia set about rethinking the entire bottom bracket and crank system with an unwavering passion for innovation. Using an elaborate lever system, the Cyfly makers have ensured that the crank length of their drive develops a greater length in the decisive areas of the downward movement, but is shortened again at the inefficient dead centres at the top and bottom.
This means that the downward pedalling leg applies more of its maximum force to the bicycle drive than before, increasing efficiency by up to 33 percent. A lever position moves the centre of rotation of the crank next to or behind the bottom bracket axle. This means that in the 3 o'clock position, you pedal with a virtual 224 millimetre long crank and thus get the torque where it makes the most sense. The eccentric deflection then shortens the crank back to its true length of 166 millimetres. As a further trick, another small lever adjusts the crank at top dead centre so that the dead centre is overcome more smoothly. At first, the pedalling motion feels somewhat angular, but after a few kilometres the riding sensation has adapted. The additional power with every downward pedal stroke is noticeable in more lively acceleration.
The elegant Möve bike from the same company, on which the Cyfly is initially fitted exclusively, develops a similar thrust to an e-bike when pedalling. Goodbye, round pedalling - it gradually becomes more of a stamping motion. But at almost 17 kilos, Möve Franklin is still quite heavy and accelerates correspondingly slowly. The Cyfly crank and its frame interface only add around two kilos to the bike's weight, but the wheels alone weigh over 5 kilos. The Cyfly drive is compatible with all derailleur and hub gears. There are also plans to use it in e-bikes, where it should provide greater battery range.
