Replacement crankset recommendations?
I've acquired a used Dahon folding bike, but the previous owner neglected it. And at some point, someone put one of the pedals in incorrectly, so the threads on one of the cranks are thrashed, and the threads on the corresponding pedal are thrashed. The chainring is rusted, and the plastic chainring guard is cracked. So I'm looking to replace the entire crankset.
What I'm looking for: crankset with a single 48T - 52T chainring and a chainguard. Preferably within a reasonable budget ($50, maybe $60?). I've considered the FSA Metropolis City, but it seems to only be available as 45T. I'm thinking about getting a Shimano FC-A050 and removing the 39T ring, but I haven't been able to confirm whether the rings are riveted.
So has anyone got any great ideas on a crankset that would work well as a replacement on a folder?