I need a new crankset for my Panasonic Sport 500. I don't know what to get. I have been hunting Ebay. I would prefer to spend under $50. There are several options on Ebay for that amount. I recently bought a Vuelta crankset but had to return it because it stuck out too far and wasn't aligning with the rear cassette. I don't want to go through that hassle again. Does anyone know what crankset is compatible with the Sport 500? I am using the standard spindle and cup setup. I am capable of changing the spindle. Should I consider using a cartridge BB? If so, which one will fit? Do I need special tools to install a cartridge BB?