The transmission from the crankset to the rear wheel can be done using a belt.
Technology borrowed from the automobile, it is generally made of kevlar or carbon.
It has the advantage of being more robust and more flexible (more pleasant pedaling) than a chain.
However, the belt requires a frame designed specifically for it and requires a little dexterity to give it the right tension.
A pioneer in the use of this technology, the high-end German company Schindelhauer only offers belt transmissions.
