GRX 11 to 12 speed upgrade

[tihojla]

Hello everyone,

my question is, what do I need to upgrade to GRX 12 speed from 11 speed.

My current setup is GRX 11 - 810, 2 chainrings 48/31, XTR 11-40 cassette.

Can I buy only right 12 speed GRX 820 shifter, 12 speed chain, and a new 12 speed cassette (11-36).
Will it work?

[warthog101]

I think the cable pull ratio has changed.

That said, they do use a revised cable pull ratio, that according to Shimano, is officially not cross-compatible with 11-speed road or Shimano’s MTB 12-speed components

https://escapecollective.com/shimano-gr ... s-on-look/

Sounds like the 11s derailleur wont work with the different 12s pull ratio.

[Treptay]

I think the cable pull ratio has changed.

That said, they do use a revised cable pull ratio, that according to Shimano, is officially not cross-compatible with 11-speed road or Shimano’s MTB 12-speed components

https://escapecollective.com/shimano-gr ... s-on-look/

Sounds like the 11s derailleur wont work with the different 12s pull ratio.

Funnily enough, the 12s derailleur apparently works on 11 speed fine
https://www.youtube.com/watch?v=dEEe0hIMpf0

[warthog101]

I think the cable pull ratio has changed.

That said, they do use a revised cable pull ratio, that according to Shimano, is officially not cross-compatible with 11-speed road or Shimano’s MTB 12-speed components

https://escapecollective.com/shimano-gr ... s-on-look/

Sounds like the 11s derailleur wont work with the different 12s pull ratio.

Funnily enough, the 12s derailleur apparently works on 11 speed fine
https://www.youtube.com/watch?v=dEEe0hIMpf0

There you go then!

[DawnBat]

This video is the R7120 STI with R8000 GS RD
Shimano 105 12 Speed Groupset With 11 Speed Rear Derailleur
https://www.youtube.com/watch?v=9u6ntnyw5vQ