Trolleys are available in both nylon wheels and steel ball bearing wheels. Nylon wheels roll better with extremely light curtains. When the curtain weight exceeds 100 pounds or the curtain height is over 15 feet steel ball bearing wheels should be used to allow the curtain to roll easily and close more fully.
Two wheel trolleys with bumpers should be used in applications where the wheels of consecutive bumperless trolleys would rub together with enough force to resist free and easy rolling action. Normally the stiffness of the curtains top hem is sufficient to push the curtain along. One situation where trolleys with bumpers are needed is when the curtain is suspended by chain from a track mounted to a high ceiling.
Four wheel trolleys roll more easily than two wheel trolleys on heavy curtains that receive rough handling.
The overlapping trolleys are used when an opening in the center of the doorway is desired. When used with curves the overlap must be on the outside of the curve.
Pull rope trolleys should be used on curtains higher than eight feet. They are used to prevent fabric damage caused by tugging on the material and they allow the curtain to close more fully. Polypropylene hollow braid rope with a 3/8 inch diameter is used. There are two holes on each end of the pull rope trolley. This allows consistent curtain grommet positioning with' either the 1/2 inch or 1 inch trolley hooks. A screw, nut and 1-1/4 inch outside diameter washer are provided for securing the curtain to this trolley. The lead trolley hole should be secured to the curtain to allow the curtain to close more fully.