Update your commercial grade swing set with the Jensen 3-1/2" O.D. Ductile Pipe Swing Hanger with Shackle Pendulum - SH114. Made from galvanized ductile iron, it is designed to hold up through most weather. The bearing itself is oiled bronze. The clamp style hanger is easy to install and cuts costs by limiting the number of parts needed to attach the swing to the swing set.
For a smaller size, check out the 2-3/8" version that boasts all of the same great qualities, with the ability to fit a smaller top rail.