Bike derailleurs still rely on the same basic mechanics that have been at the core of bicycle shifting since its advent, in the early 1900s. But major manufacturers are now developing electronic systems that promise faster and more precise shifts, lighter weight, customizable features, and improved ergonomics. Though nothing's official, production versions could be offered as early as 2009.
1. Computer: Integrated computers might register not only the usual speed and distance but also the current gear and remaining battery life.
2. Wires: Shifters and derailleurs will still be linked, but instead of steel cables pulling levers, it will be insulated wires carrying electrical impulses.
3. Hoods: Since designers won't have to contend with bulky mechanical internals, they'll be able to deliver more ergonomic shapes and possibly even built-in gear indicators on the brake hoods.
4. Battery: Power will come from an on-board battery. Lightweight lithium-ion cells are small enough to integrate into existing parts, such as water-bottle cages, and would last for days on a single charge.
5. Derailleurs: They won't look all that different. But inside, fast-acting motors will deliver quick, precise shifts of up to several gears at a time. There will likely be adjustment screws like those on current models.