Acs freewheels will come loose on the front so dont worry its not just you who has problems with this, run a different freewheel on the front like a eno, tensile or Monty. These are available from tarty bikes , hope i helped because i had the same worry when i first started. .. i do know what you meen, the unscrew, its annoying because you have to constantly tighten it but like i said the front freewheeling designed freewheels will not come loose