Isn’t it a slightly longer first linkage of the mech? So the bolt to the right in that picture is the mech fixing bolt, and the hole on the left is for the first pivot? i.e. it replaces the bit between the two bolts in the top left of this picture:

That should set the whole mech a few milimetres backwards and reduce how far back it has to stretch to hit your 42T sprocket.

Sound about right?

Yup that makes sense

What I can’t get my head round is whether it achieves the same thing as the One-Up RAD cage or not. I reckon it probably does, but I’m so mechanically dim that I’m not sure….

🙂

Bingo!