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The concept

The mechanical crank drive system for bicycles was invented around 150 years ago and has hardly been improved since. We took the drive system further and developed the cyfly Easy Cycling Technology. For more fun and for more efficient cycling. Whether you want to go higher to the top of the next hill, faster to the office or further to a distant milestone.

The cyfly drive system

The drive system

cyfly is a patent-pending, purely mechanical bicycle drive system powered exclusively by muscle strength. With this novel design, gears and levers work together in an optimised “multi-jointed crank”.

With the cyfly drive system, we move along the path of a crank with a length of 166.5 mm (6 9/16" )and generate the torque of a crank with a length of 223.9 mm (8 13/16"). We increase the torque by 33 % in the 3 o´clock position.

Powerful cooperation partners

Our idea to make the mechanical bicycle drive system noticeably more efficient has inspired numerous powerful industry and research partners. Only through joint development were we able to make the cyfly Easy Cycling Technology what it is today: high technology from Germany for a global market. Our thanks go out to everyone who believed in us for the past three years!

The cooperation partners in Germany

MITEC Automotive AG
MITEC Automotive AG from Eisenach is one of the world’s leading companies for automobile transmission technology. It has been supporting us with prototyping since 2014 and continues to be our strategic partner for the production of cyfly components in the highest precision.

Schaeffler Technologie AG
We have been working with Schaeffler Technologie AG in the development of grooved ball bearings since 2013. Our cooperation with Schaeffler will be expanded going forward.

Schmalkalden University of Applied Sciences
Thanks to our cooperation with Schmalkalden University of Applied Sciences, we will be able to produce cyfly components made of materials such as carbon or natural fibres with the help of 3D printing methods here in Germany.

Leipzig University
With the Faculty of Biomechanics at Leipzig University, we are researching the positive effects of the cyfly drive system on the movement sequence while cycling.

Questions and answers

  • Contrary to what is generally assumed, the pedalling motion of cyclists does not drive the bike continuously. The rider actually “shoves” the bicycle forward in spurts with the leg that is on the downward stroke. This is in the range between 2 and 4 o’clock. Cyclists using click pedals also pull on the pedals during the upward stroke. To keep things clear, this happens between 8 and 10 o’clock. Only minor forces that are not capable of driving the bike can be applied in the upper and lower ranges (dead centres).

    Our cyfly drive system is designed to utilise the force noticeably more effectively, precisely in the force application zones (3 o’clock, or with click pedals also 9 o’clock). cyfly generates higher torque with the same effort. With cyfly, you ride more easily and/or even faster than before. cyfly works entirely without any electricity or other external energy source. Your performance is improved compared to conventional crank drives. Purely through mechanics using your own strength. That means you will not feel the permanent acceleration power of an eBike – but will probably not miss it either.

  • cyfly is an innovative drive system for bicycles, with several pending patents. With the cyfly drive system, the crank is no longer connected directly to the axle but supported behind it. Thereby cyfly increases leverage in the driving and lifting phase while pedalling. The pedal travel is shortened as well. This noticeably improves the leverage.

  • cyfly is a combination of gears and levers. In principle, cyfly generates the torque of an extremely long crank (length over 223 mm) in the relevant zones by means of a lever extension. However, the pedal only travels the total path of a very short crank (166.5 mm) with each revolution. This results in significantly greater performance with the usual pedalling frequency. You will most likely feel the effect during striking downwards after you have passed the upper and lower ranges (dead centres).

  • No. In contrast to a conventional torque converter (dérailleur gears and gear hubs), cyfly is a special force converter that, unlike conventional systems, does not lengthen the pedal travel to increase the torque. cyfly can be combined with a conventional gear shift to use a broader range of gears.

  • The chain ring is only similar to other systems in appearance. An oval chain ring is secondary with cyfly. The main point is that the cyfly crank – unlike a conventional crank – is not directly connected to the chain ring at all. These novel kinematics result in a different pedalling feel. We especially adapted the chain ring to the movement sequence, only in order to minimise the difference between our drive system and “familiar” round pedalling. cyfly as an innovative bicycle drive system also provides a novel pedalling feel. We hope you enjoy this exciting experience.

  • Thanks to the permanently higher torque, higher transmission ratios can be used with the cyfly. We will install higher transmission ratios upfront and you will feel the effect during pedalling as comfortable and easy. A 46 tooth chain ring is installed on a mountain bike with the cyfly drive system and a 48 tooth chain ring on a trekking bike with the cyfly drive system. The conventional cassettes can continue to be used with no loss of comfort.

  • cyfly is located in the position of a conventional bottom bracket. It replaces the entire front section of the drive train on a conventional bicycle. The cyfly drive system includes cranks, bearings and the patent-pending chain ring. All components are produced using highly modern production technologies. cyfly is state of the art.

  • Since the cyfly drive system requires a precisely adapted frame, it cannot be retrofitted readily. Initially cyfly will only be available as an innovative component of premium bicycles.

  • cyfly weighs about 1,950 grams. After eliminating the components that otherwise make up the drive, the net difference with the cyfly drive system is: crankset with axle and bottom bracket. Thanks the torque increase, the additional mass literally “carries no weight”, especially when going uphill. Furthermore, the driving characteristics are positively influenced by the favourable weight distribution in the frame’s centre of gravity.

  • Initially the complex cyfly drive system will only be offered pre-installed in premium bicycles.

    Bicycles with the innovative cyfly drive system will be available starting in 2017. Please visit our Facebook page for current information about availability and prices.

  • Everyone applies force differently while cycling. Therefore we cannot provide an objective, generally applicable gain in efficiency. The value is calculated based on data with established constraints on the one hand and a significant number of field tests on the other hand. The efficiency gain was also verified by an external expert opinion from a bicycle laboratory in Freiburg, Germany. Furthermore, the cyfly effect was confirmed by renowned bicycle racing and triathlon professionals. See the “Response to the cyfly” section for their feedback.

  • No, unfortunately the calculation is not that simple. Naturally the gain in efficiency affects the speed. A higher torque is produced with the same effort compared to a conventional crank. As a result, most cyclists “automatically” select a higher gear ratio and go faster. However, air resistance also plays a major role at higher speeds.

    Field tests have shown that our test drivers are 3-4 km/h (2 - 2.5 mph) faster at the same pulse rate. Starting with an average speed of 24 km/h (15 mph), you would for example need approximately 40% greater performance to travel at an average speed of 27 km/h (17 mph)..

    You can reproduce this calculation at kreuzotter.de/english/espeed.htm if you are interested.

  • You can feel the efficiency gain of cyfly in demanding riding situations in particular: going uphill, starting off in a high gear, towing a trailer or going against a strong headwind; whenever a lot of force is normally required.

  • Technically, efficiency is not defined in concrete terms. However, this term is often used to explain that product A performs better than product B under the same conditions. Fuel consumption example: with the same distances travelled, the more efficient engine needs less fuel than the comparison engine. The effectiveness of a machine can also be used for efficiency. We use the term efficiency exactly as in the engine example to explain how you get more performance with the same effort or unchanged performance with less effort when using cyfly.

  • Performance can be measured in various ways. Watts are used a lot in the bicycle sector. These methods measure the transmitted torque [N*m] using strain gauges or other sensors (e.g.: in the spider, at the pedals or in the rear axle). When the pedalling frequency [1/s] is also taken into account, the performance can be calculated [Watt=N*m/s].

    Torque and performance are related and very well suited for comparing the cyfly drive system to a conventional crank. Therefore one can say that both get more efficient.

  • To grasp the unrealised potential, it is important not to view the crank as a self-contained drive element. 
Rather the crank is only part of the complex human <> bicycle drive function.

    The high-tech cyfly drive system optimises the interplay between human and “machine”. We will continue working hard on this optimisation.

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