Three remarkable innovations are transforming the mechanics of the common bicycle. In fact, these new technologies may be the most significant developments in bike engineering since the original "safety" bicycle was invented at the end of the 19th century.
Shimano, makers of high-end bike gear I can't afford, is making a push for its Di2 battery-powered gear shifter. Why make the time-tested bicycle design more complicated and harder to service? Aerodynamics.