Must be getting too old, yes it was the B tension, it was screwed in all the way so backed it off until they were not touching, all sweet now.
It was the ultegra 12 – 30 (6700) cassette so I assumed it would be safe however looks like the 6600 rear mech is max 27t, however look’s ok at the moment.
Not touching and changing on the rear ok, needs a bit more tweaking for the front or would I have made it impossible to get the front right with what I did?
Anyone care to say if anything bad is likely to happen or can I just suck it and see?
Why am I doing it – for a trip round the lakes needed some low gearing