Well i thought the tryall ones were the same as the acs claw one, got 4 counter sunk tabs. Ifso the only way's i can think of removing it is: Use a chizel and hammer keep hitting the sunken tabs round, its worked for me in the past after smashing it for some time. or If you dont want the freewheel anymore i,e its broke, strip the freewheel right down and put the remaning part of the freewheel in a vice and yank on the crank arm till it comes loose, if you know what i mean. Hope you get it off as freewheels can be a real pain to remove.