One up rad cage moves the jocky wheel back £20ish
Don’t think jockey wheel is the problem, happy to be corrected. (see the pic).
Sure the mech is bolted on correctly and the b-screw doing its job correctly?
yeah think so
Bit curious about the frame, I suppose it’s possible the mech/hanger position is doing something weird? There’s more than enough clearance normally.
How sure are you everything’s straight?
it’s a new frame, had the same issue on another frame (tho this is the first time I have diagnosed it fully).
frame rides straight, it’s a 142×12 axle on sliding dropouts
Best guess is that the arm is bent and/or twisted.
RM is new, good theory but I don’t think so. I’ll look as it seems a good theory.