I rescued a bike from the trash and want to convert from 7 speed to 9 speed. The biggest sprocket has "Lock Ring Type" printed on, so I assumed it was a 7 speed cassette (and I wanted to see if the free hub is a modern type that fits a 9 speed cassette).
However after taking the wheel out I noticed it looks like a freewheel rather than freehub with cassette. Why does it say "Lock Ring Type" on the biggest sprocket? Is this actually a freehub with a lockring that's unfamiliar to me?