Wikipedia
The Stringbike is a bicycle that uses a rope and pulley drive system instead of a traditional bicycle chain and sprockets. It uses two Dyneema ropes attached to pulleys attached to swinging lever and cam mechanisms, one on each side of the bike. These mechanisms replace the round sprockets found on chain-driven bikes. Unlike some traditional 10-speed gears using a derailleur, there is no slippage when changing gear ratios. The Stringbike uses a 19 gear ratio system with no duplicates and a total gear range of 3.5 to 1. The transmission ratio can be changed with a shifting knob located on the right-side handle grip. Gear ratios can be changed even when the bicycle is almost stationary.
Hungarian designers from the manufacturing company Schwinn Csepel Zrt, unveiled the bicycle in 2010 in Padova, Italy.