Rope Sheaves are for fibrous rope. They have a full radius or groove. Wire rope Sheaves are "v" grooved, cradling the wire rope to prevent it from coming out of the groove. Wire rope sheaves are up to 3/8" maximum diameter and go up to 1" rope. Wire rope is not as flexible as regular rope, so it is not advisable to use wire rope in a regular rope sheave, because it will force the wire rope to bend around too tight a radius. This can cause it to bunch up, and unwind.
Ball Bearing Sheaves are used on a continuous run situation, constant revolutions.
Bronze Bushings are more durable and can withstand a heavier load, but are intended for a slower use and not rotating continuously.
Another bearing is not necessary for use along with the bronze bushing. We use "660 bronze" which is a leaded tin bronze. It allows rotation with very low friction.
For more information please visit www.ssdirect.net