If there's rust on the chrome and it's not too bad, you can try Nevr-Dull wadding polish. If it's really bad, you can try an oxalic acid bath. Oxalic acid is great, but don't use it on anything but steel. It will eat aluminum and if there are zinc galvanized steel parts (spokes) it will eat the zinc and leave it looking cloudy.
This post probably belongs in the general C&V forum though.