I pulled the small and large rings as well as the front derailler off an old hybrid to turn it into a 7X1, and was shocked to find that while the 7 spd rear derailler and cogs were functioning just fine, as I shifted into the lower gears the chain was being thrown to the inside of the now single speed ring.
Inspection showed a few really worn teeth, could that be the problem?
I had thought a single ring would always keep the links on the teeth no matter what!