Thanks - I intend to fit a new chain, so I will adjust the length accordingly, as I am replacing 22-32-42 chainset with 26-38-48 triple and not using the large 48 ring. The old 11-28 cassette and 22-32-42 chainrings are all badly worn, hence the need for replacement - I just happen to have an old (unused) 26-38-48 Sugino crankset. I have yet to get a cassette but I think I will go for a Shimano HG50 11-34, and see how I get on. I am unable to find a serial number or any identification on the Sram derailleur, so maybe I'll have to replace that too! It seemed to work fine with the old set-up, notwithstanding damaged teeth etc.