• The tensioning (bottom) jockey wheel was particularly worn and the chain was slipping off to the side of and jambing and damaging the derailleur frame so I ordered a replacement from Chain Reaction. You can see from the photo above just how worn the wheels were.

photo showing how worn the jockey wheel was and damage to derailleur cage

• They came as a set. In the photo above and below the one with the white writing on it is the Tensioning wheel and it actually sits at the bottom keeping the chain tension, while the other wheel is called the guide wheel and it sits closest to the cassette, guiding the chain onto the cassette.

Note the bolt in the bottom of the derailleur is NOT original and was installed in Morocco in 2013.