Is it stick on the freehub? When mine did that I just jiggled it side to side as much as possible and then left it as far as poss to the opposite side it had been at the start, then took a big hammer to it
Large flat head screw driver down behind biggest ring and hub and twist. If its a pro2 you can get a smaller flat head in the end of the free hub grooves and twist. Remember to shout at the same time as twisting " come on ya f…… b…… c…" Should work.
Beat me to it. Lock ring eh. Long bar on the ends of chain whip and ratchet and shouting.
I use an oil-filter wrench rather a chain-wip. More chain in contact with the sprockets as there is loads of it results in a tighter hold. (also £15 cheaper than a chain wip) Really massive spanner helps too.If you are anywhere near Cardiff you can borrow my 18-inch long adjustable (I don't live in Cardiff, but lent it some time ago to someone who does and keep meaning to get it back from him…)
If your chain-wip has plenty of grip put your cassette-tool face-up in bench vice and turn the whole wheel for extra leverage.