Originally Posted by
hueyhoolihan
IME, a chainwhip is necessary to loosen a cassette lockring not tighten it. but one of these is necessary to do either.
Right, I thought I saw an info page suggesting the whip to tighten, but if your freehub, hub, and spokes can take pedalling, then they can take occasional tightening the cassette.
Personally I like to have all the maintenance tools I might need. For example, the chain whip would be necessary to replace a broken spoke.
Make sure the tool is for a cassette, and not a freewheel.
For example:
Park FR-5
Of course, there are other brands/models.