How to replace the indicator chain on the SRAM 3×7 hub
The small chain leading into the three-speed hub broke. (This refers to the SRAM 3×7 three-speed hub, formerly the SACHS 3×7 hub.)
This tiny chain is called the indicator chain. It runs into the hub and is pulled by the cable attached to the shifter. There are two pieces: the indicator chain itself, and the black plastic cable anchor that binds the chain to the cable.
The chain does come under a certain degree of stress and may need to be replaced from time to time. If it breaks, read on.
- Remove the broken piece of indicator chain in the cable anchor by pressing the metal tab on the anchor and pulling out the stub of chain.
- Pedal forward a full revolution or so, so that the hub is shifted into high gear by spring tension.
- Lay the bike on its left side, chain side up.
- Grab the stub of the indicator chain in the axle end with your fingers, or gently with pliers if it is too short. Turn the chain counter-clockwise like a bolt and it will unscrew easily.
Tip: Remove the right side axle nut to expose more of the broken chain, if needed.
- To reinstall, drop the end of the indicator chain with the smooth shaft and small threads into the axle hole until it stops. Turn the chain gently clockwise, like a bolt, until you feel it stop. Do not tighten. Just turn the chain until you feel it stop and then back off one-quarter turn.
Tip: You will find the indicator chain easier to install with the axle nut on and tightened down. Dangle the chain into the locknut hole.
- Reconnect cable anchor and adjust as outlined in “To reinstall the rear wheel” (see related articles, below).
- Call Bike Friday to order another indicator chain for future adventures, or select it from the on-line catalog using the button below.