This steep, narrow, twisted, dusty, and often muddy path runs from the freezing Cumbre summit set high in the Bolivian Andes down to the boiling Yungas forests still high above the sea at 1500 m. Imagine the first to suggest it as a nice cycling route!
Even more interesting is to think of who was actually the first to venture down the risky 80 km long cycling route. That must have been someone truly careless, somewhat crazy, brave-hearted, and not afraid of death. We will never find the truth about the real origin of the dreadful road, but nowadays numerous extremists are eager to try their skill and experience the huge pump of adrenaline from the trip. If you feel up to the challenge, you are welcome, but some safety measurements are still to be undertaken.
The most convenient time is winter—June to August, though it is really cold in the highlands it is also dry and hence safer to ride. Besides make sure to wear a few layers of clothes, since you are going to descend into warmer climates and finish in the Bolivian jungle.