with my walmart Next folder, and as an experiment with my Schwinn tango, both with the same low quality 6 speed (14-28), i tried a 52T crank with a longer crank arm that i took out from another bike. that provided a nicer range - in particular the high gear, so it was less spinning. this just required adding some chain links, and swapping the crank. but did not need a lot of any other work if one decided to replace the cassette. in the long run, they were still both very poor frames to do any more work on, and not worth the time and effort.