There are two types of links alternating in the bush roller chain. The initial type is inner links, having two internal plates held together by two sleeves or bushings upon which rotate two rollers. Inner links alternate with the second type, the outer links, comprising two outer plates held together by pins passing through 
the bushings of the internal links. The “bushingless” roller chain is similar in procedure though not in construction; instead of individual bushings or sleeves holding the inner plates with each other, the plate has a tube stamped into 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 in comparison to simpler designs, leading to higher efficiency and less wear. The initial power transmission chain types lacked rollers and bushings, with both inner and outer plates held by pins which directly contacted the sprocket the teeth; nevertheless this configuration exhibited incredibly rapid use of both the sprocket tooth, 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 moving through bushings or sleeves connecting the internal plates. This distributed the use over a greater area; however the teeth of the sprockets still wore quicker than is attractive, from the sliding friction against the bushings. The addition of rollers around the bushing sleeves of the chain and offered rolling contact with one’s teeth of the sprockets resulting in excellent resistance to put on of both sprockets and chain aswell. There is even suprisingly low friction, provided that the chain is definitely sufficiently lubricated. Constant, clean, lubrication of roller chains is of major importance for efficient procedure in addition to correct tensioning.