There are two types of links alternating in the bush roller chain. The 1st type is internal links, having two internal plates held collectively by two sleeves or bushings upon which rotate two rollers. Internal links alternate with the next type, the outer links, comprising two external plates held jointly by pins moving through the bushings of the internal links. The “bushingless” roller chain is comparable in operation though not in building; instead of separate bushings or sleeves holding the inner plates jointly, the plate includes a tube stamped involved with it protruding from the hole which serves the same purpose. It has 
the benefit of removing one part of assembly of the chain.
The roller chain design reduces friction compared to simpler designs, leading to higher efficiency and less wear. The initial power transmission chain varieties lacked rollers and bushings, with both the inner and external plates held by pins which directly contacted the sprocket the teeth; however this configuration exhibited incredibly rapid put on of both sprocket the teeth, and the plates where they pivoted on the pins. This issue was partially solved by the advancement of bushed chains, with the pins keeping the outer plates moving through bushings or sleeves linking the inner plates. This distributed the use over a greater area; however the teeth of the sprockets still wore more rapidly than is desired, from the sliding friction against the bushings. The addition of rollers around the bushing sleeves of the chain and supplied rolling contact with the teeth of the sprockets resulting in excellent resistance to put on of both sprockets and chain aswell. There is even suprisingly low friction, as long as the chain is usually sufficiently lubricated. Constant, clean, lubrication of roller chains is of main importance for efficient procedure and also correct tensioning.
