hi, in theory no as all towballs are 50mm the alko hitch will fit all balls. HOWEVER wether a alko hitch has enoough clearance between the hitch and the body work of the car is another story providing there is a least 25mm of clearance once the hitch is fitted on to the ball it should be ok.
if not alko do a ball that sits farther out from the tow bar mount giving more room.
the main thing about using an old ball with the alko is that is has to be absolutly clean with no sign of damage, grease or rust as this WILL contaminate the friction pads.
ok colin