• Wheel: in your set of fixtures, this is an element designed to fasten the pipe and the engine during the operation of the roller shutter. It will be located between the engine head and the pipe. You should put it on the motor housing before inserting the ring and screwing it into the winding tube.
• Ring/Crown: it is placed at the opposite end of the engine head. Completely hidden in the axis of the blinds, when the motor is installed, it allows you to accurately position the motor housing along its entire length and counts the number of revolutions made within the limit switches. It should be installed only after you put on the wheel.

Crowns and wheels are necessary for a tubular motor for roller shutters . It is extremely important that they are present, positioned correctly and in perfect condition to ensure their operation and protect the shutter from indirect damage, be sure to replace them in case of wear. Does the shutter not stop in the upper or lower position? Check the ring/crown in turn, it may be incorrectly installed or broken. And a wheel that may not be able to count the revolutions correctly