Yeah I guess what I've heard is that if you use a narrow chain (for some reason people mentioned 9 speed chains) that it's easier for your old 10 or 12 speed to shift. The current problem I'm having is that I placed a new cog and a wheel set (27 in) and when in the lowest gear (smallest rear cog) the chain skips, but only in this gear. I thought maybe I had the limiting screw to tight or something, but it seems fine. Someone explained it to me in that sometimes chains will stretch over time, and not match with certain cogs, so you need to replace the chain. They suggested a 9 speed narrow chain. My questions is, do I need to chain to match the speeds? (stupid question, but not sure why people suggest chains other than 10 for 10s, and 12 for 12s etc...). Is it more the amount of links in the chain? Would the 8 speed chain be shorter than a 10 speed chain?