Originally Posted by
raisinberry777
The RX812 is for 1x only. The RX810 is the equivalent model for 2x. Its range is the same as the 105 R7000 GS rear derailleur, which allows for a maximum 34 tooth in the back. However, some people have found that in practice, you can easily run an 11-36 or in some cases, an 11-40.
Thanks for the response. This is the info that Shimano provides below:
"RD-RX810/RD-RX812
- SHIMANO SHADOW RD+ stabilization
- Compatible with existing 11-speed mechanical DUAL CONTROL levers
- Max. cassette range:
- RX810 (30-34T low)
- RX812 (40-42T low)
- Max. front chainring range: 17T (RX810 only)
- Capacity
- 251/264 g "
Not sure if the RD will be compatible with the 105 hydro shifters. If so... then I might bite the bullet and install an bigger cassette and run this RD. Chainline would be something else I would be worried about.