Repairing a broken chain

If your chain has snapped, it’ll be 1 pretty obvious where the broken link is. If it’s just skipping, you’ll need to identify the damaged link. Back-pedal the cranks and when the offending link passes over the rear mech’s jockey wheels the chain will jump. Modern SRAM mechs have a 2 ‘Cage Lock’ to take the tension out of the chain. On other mechs, you’ll need to use a chain hanger/bent spoke to hold the chain ends together, with some overlap (switch the clutch off first on Shimano Shadow Plus mechs). If you have a master link, ensure 3a that the broken link is on the upper section of chain (above the chainstay). Then use a chain tool to push out the pin holding the broken outer link to the next inner link (turning it clockwise). Remove the chain tool and the broken link. Attach a master link plate to each 3b end of the chain, ensuring that they face in opposite directions. Push them together until they lock. Put weight on the forward pedal while holding the rear wheel still. This should tension the chain and snap the master link into place.

If you don’t have a master link, 4a you’ll need to remove the broken link and rejoin the chain. Ensure that the broken link is on the lower section of chain (below the chainstay). Use the Cage Lock or a chain hanger to de-tension the chain, so that the ends hang down. On the end with the broken link, 4b find the next undamaged outer link and use a chain tool to push the nearest pin just far enough (clockwise) so the inner link can be removed. (On a skipping chain, first break it by pushing one pin of the damaged link fully out.) Align the inner link at the other 4c end of the broken chain with the pin you’ve just pushed through the outer link. Use the chain tool to push the pin back through the new link until it’s almost flush. If the link is stiff, wiggle it from side to side until it moves freely.