Do I need a tool to install and remove the AXS battery from the derailleur? No, AXS batteries are installed and removed using a tool-free latching mechanism. Related articles Do I have to remove the eTap® derailleur batteries to charge them? How do I charge eTap AXS derailleur batteries? How do I update firmware using the AXS App? How should I store my AXS equipped bike and derailleur batteries during the off-season or when the bike is not in use for 2-3 months or more? What type of batteries do eTap AXS shift-brake levers require?