How to size a SRAM GX Eagle 12-speed chain — SRAM’s own method from their service docs. Each rule sourced.
How to size a SRAM GX Eagle 12-speed chain — SRAM's own method, straight from their service docs. There's no single link count: you measure it on your bike, and full-suspension frames add a step. Each rule below is from SRAM.
| Component | Attribute | Value | Src |
|---|---|---|---|
| Base method | How to measure | Wrap the chain around the largest chainring + largest cog, bypassing the derailleur, flat edge facing away | [1] |
| Hardtail / rigid (1x) | Links to add | Add 2 inner + 2 outer links (4 total) where the chain starts to overlap | [1] |
| Full suspension | Links to add | Compress the shock to the point where the rear axle is farthest from the BB, then add 1 inner + 1 outer link (2 total) Deflate/remove the shock if needed to reach full compression. |
[1] |
| Exceptions | Different for AXS / XPLR | Full-mount rear derailleurs (incl. 13-speed XPLR AXS) size differently — use SRAM's XPLR chain-length section | [1] |
Rebuilding a boxed mountain bike for a trip? Get the chain length right first — too short and you'll wreck the derailleur in the big-big gear on the first climb.