There are two types of links alternating in the bush roller chain. The initial type is inner links, having two inner plates held collectively by two sleeves or bushings upon which rotate two rollers. Internal links alternate with the second type, the external links, comprising two outer plates held jointly by pins passing through the bushings of the inner links. The “bushingless” roller chain is similar in operation though not in building; instead of separate bushings or sleeves holding the inner plates collectively, the plate has a tube stamped involved with it protruding from the hole which serves the same purpose. This has the advantage of removing one step in assembly of the chain.
The roller chain design reduces friction compared to simpler designs, leading to higher efficiency and less wear. The original power chèn transmisyon varieties lacked rollers and bushings, with both inner and external plates held by pins which directly contacted the sprocket the teeth; nevertheless this configuration exhibited incredibly rapid wear of both the sprocket teeth, and the plates where they pivoted on the pins. This problem was partially solved by the development of bushed chains, with the pins keeping the outer plates passing through bushings or sleeves connecting the internal plates. This distributed the wear over a greater area; however the tooth of the sprockets still wore more rapidly than is desirable, from the sliding friction against the bushings. The addition of rollers surrounding the bushing sleeves of the chain and offered rolling contact with the teeth of the sprockets leading to excellent resistance to put on of both sprockets and chain as well. There is even very low friction, so long as the chain is usually sufficiently lubricated. Continuous, clean, lubrication of roller chains is usually of major importance for efficient operation and also correct tensioning.