freehub not spinning after cassette change

[Rob_T]

i was getting my bling wheels out of the garage. the freehub was working fine, spinning nicely. took the cassette off it and replace it with a different one (still shimano cassette on shimano hub).

tightened it up. may have overtightened to be fair. next thing is freehub is not longer 'free'. took the cassette off and it's still not spinning freely but requires some effort to turn it.

any ideas what i've done to it and how i can fix it?

[NitroNick]

Check if the largest cog is touching the spokes.
It might need a spacer between the largest cog and the inside of the hub.

[MadDad]

Depending on the bearing in the hub, if you have overtightened it you may have crushed the bearing race.....I would imagine that would be quite difficult to do but it is possible.

[gazza285]

Most likely you have pushed the seal that sits inside the free hub in with the cassette tool.