Replacement freehub for a Shimano FH - 5501 freehub

There are two ways to do this. You can buy a used part - they are available and not that expensive (and not super hard to service if you have the right lubes and tools.) You can also buy a brand new freehub. As long as you buy a Shimano freehub that is rated for 9 speed (which should be most of them) you should be good to go. Here’s a link to a compatibility chart for freehubs. Mountain bikes are slightly different, but are also covered in the compatibility chart. As long as your spacing for the cassette and the pattern of splines are matched, you’re good to go.

https://www.lightbicycle.com/newsletter/...