Sorry for cjipping in but have a similar problem 3rd time this is happening to me normally it is fixed after a service but then 2 or 3 rides later it starts again, symptoms are as follows: Only happens when in largest sprocket on the cassette (granny) and only when paddeling hard (steep hill) 1) Does the RD remain completely stable Left-Right but the chain rides on top of the teeth of the cassette? Can't say haven't had time to check it yet started happening yesterday 2) Does the RD move left or right and then just partially engage the chain onto the next gear? Can't say haven't had time to check it yet started happening yesterday 3) When pedalling hard in certain gears. Yes 4) When just pedalling along with very little pressure on the pedals. No 5) In the workstand right there in front of your eyes. Not checked yet 6) Are the speeds on the cassette and chain and shifter matched? Yes 7) Does the shifter move the cable smootly in even incriments when the cable is removed from the RD and tensioned in one hand whilst shifting with the other? Will check tonight 8) Is the jockey hanger properly fixed onto the frame? Yes Thanks JB now I have some point of referance to start trouble shooting from. will report back tomorrow
