There are two types of links alternating in the bush roller chain. The 1st type is inner links, having two inner plates held collectively by two sleeves or bushings upon which rotate two rollers. Inner links alternate with the second type, the outer links, consisting of two outer plates held jointly by pins moving through the bushings of the inner links. The “bushingless” roller chain is similar in procedure though not in construction; instead of individual 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, resulting in higher efficiency and less wear. The initial power transmission chain varieties lacked rollers and bushings, with 
both the inner and external plates kept by pins which straight contacted the sprocket teeth; however this configuration exhibited incredibly rapid put on of both sprocket teeth, and the plates where they pivoted on the pins. This problem was partially solved by the advancement of bushed chains, with the pins keeping the outer plates passing through bushings or sleeves connecting the internal plates. This distributed the use over a Conveyor Chain larger area; however the tooth of the sprockets still wore more rapidly than is desired, 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 resulting in excellent resistance to wear of both sprockets and chain aswell. There is even very low friction, as long as the chain is definitely sufficiently lubricated. Continuous, clean, lubrication of roller chains is usually of primary importance for efficient procedure as well as correct tensioning.