Tired of broken chains and faulty derailleurs, Hungarian company StringBike set out to create a drivetrain that never fails. Doing away with the greasy chain, derailleur, gear shift, and other related parts, StringBike replaced all that metal with a rope based technology.
Similar to ropes used in fitness equipment and sailing, the strong, durable, and flexible Dyneema strings are paired together with a new drivetrain design. Two identical but opposed driving units are mounted on each side of the bike frame. When the pedals are in motion, a swinging arm rotates back and forth around a shaft in the bottom of the frame.
The forward arm motion pulls on the string wound around the a drum of the rear hub, which in turn makes the rear wheel rotate. As the arm moves backward, the rope is rewound around the rear hub, ready to be pulled again. Since both drivetrain sides mirror each other, one arm is always moving forward, rotating the rear wheel.
Continuous shifting through 19 gears is achieved by using a single hand grip. Shifting is possible either under full load or when coasting. Springs in the drivetrain system help you to pedal forward, very convenient for uphill or long day riding.
The StringBike drivetrain provides a smooth, quiet, and gentle riding experience. No lubrication is required to keep the drive train running efficiently. Rain, snow, mud, or sand supposedly do not affect the performance of the StringBike drivetrain either. Unlike conventional bike chains, the string will last for up to 10,000 km.
The current StringBike drivetrain is designed for trekking and city bikes, but wider gear ratios are currently being developed for use on mountain and road bikes.