Traditional mechanical shifting uses a ratchet mechanism to pull a specific length of cable to move the derailleur into each position on the cassette. The spring loaded ratchet in the shifter pulls against the spring in the derailleur and these two elements work in combination to keep the derailleur in the right position for each gear.Electronic shifting uses servos to move the derailleur into the correct spot for each gear on your cassette. In the electronic drivetrains from other bike companies, the servos and electronics are pre-programmed and embedded into the moveable members of the derailleur.Electronic shifting with the D1x Trail uses a hybrid approach - you keep the simple mechanical derailleur that's already on your bike and update the mechanical ratchet on your shifter with a programmable servo that works with any number of gears and any derailleur. This means that if the derailleur gets bent, or your drivetrain wears unevenly, the D1x Trail Shifter can be reprogrammed to keep giving you precise shifting on the bike you love to ride.