WStewart
New Member
I want to swap the rear, external derailleur (Shimano XT) for an internal derailleur (~Nexus 7). I've found lots of good wheelsets for sale online and now that it will fit into the frame, but there's one question I can't find an answer to: How do I make sure that the rear cog on the new derailleur, front chainring (there will be just one), and the chain will all match? I know that not all chains fit onto all styles of gears. So, other than just trial and error, is there some way of knowing (before I buy the parts) that the cog and chainring are suitable for the same chain?