Originally Posted by
ThermionicScott
Careful shopping, any Shimano 14-28 7-speed you see online is likely to be a freewheel, not a cassette. This 12-28 should work (I think RSX was Hyperglide-only):
https://www.amazon.com/SHIMANO-Speed...dp/B007Y5HFWU/
Unfortunately, Shimano has stopped making upper-level 7-speed cassettes, so you're not likely to find much except for inexpensive 11-28/12-28/12-32 unless you search for old stock.
I'll be sure to avoid a freewheel.
This hub takes both Hyperglide and Uniglide. I thought RSX had a version that accepted both but maybe not. That could make it an RX-100 then. Thanks for the link.