Chain Sizing (New Chain Length)

Procedure

1. Remove the old chain

   (note its length by counting links if possible).

2. Bypass the rear derailleur

   — drape the new chain through the front derailleur, around the largest chainring and largest cog, but not through the rear derailleur cage yet.

3. Pull the chain ends together

   until they meet snugly around the big-big combo (no slack, no stretch).

4. Add 2 full links (1 inner + 1 outer pair)

   beyond the meeting point. This accounts for routing through the rear derailleur.

5. Mark the link

   where you'll cut.

6. Break the chain

   at the marked point with the chain tool.

7. Route through the rear derailleur

   (over the upper jockey wheel, around the lower jockey wheel cage tab, under the lower jockey wheel).

8. Join the chain

   with a quick link or by pressing the pin (see 3.6).

9. Verify by shifting through all gears

   — chain should not bind in big-big and should not have noticeable slack in small-small. If it slaps or sags in small-small, it's too long; remove a link.