MTB electronic drivetrain parts

Electric mountain bike drivetrain parts

A wireless drivetrain requires few parts, but they are essential: without a charged battery, the derailleur no longer moves. SRAM AXS and Shimano Di2 are covered here.

Batteries

• The battery SRAM AXS is shared by the derailleur, shifter and Reverb AXS seatpost: one reference for the entire bike.
• Shimano uses internal batteries depending on the groupset, housed in the frame or seatpost.
• A spare battery in your bag prevents a ride being cut short: it can be swapped in seconds.

Chargers and cables

• The chargers are specific to each system and are not a substitute.
• Multi-port chargers allow several batteries to be charged at once.
• Extension cables are used for setups where the battery is not located in the same place as the electronics.

Protection

The rear derailleur battery cover is the part most exposed in a crash on the drivetrain side. Replacing it costs only a few pounds and prevents you from losing a battery halfway down a descent.

See also: MTB rear derailleurs · MTB gear shifters · Complete mountain bike groupsets