I know it sounds stupid... But if your going to use a bicycle chain from a shop, pay attention to the width of the chain. I haven't had chance to measure the chainrings on the C5 (I misplaced my digi callipers) but I have a feeling they'l be 1/8th inch which is single speed bicycle chain. Don't quote me on that. I'm sure someone more knowledgeable will be able to come up with the measurement.