There are two types of links alternating in the bush roller chain. The initial type is inner links, Conveyor Chain having two internal plates held together by two sleeves or bushings where rotate two rollers. Inner links alternate with the next type, the outer links, consisting of two outer plates held with each other by pins passing 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 keeping the inner plates together, the plate includes a tube stamped into it protruding from the hole which serves the same purpose. It has the advantage of removing one step in 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 varieties lacked rollers and bushings, with both the inner and outer plates held by pins which directly contacted the sprocket the teeth; however this configuration exhibited extremely rapid put on of 
both sprocket the teeth, and the plates where they pivoted on the pins. This problem was partially solved by the development of bushed chains, with the pins holding the outer plates moving through bushings or sleeves connecting the inner plates. This distributed the put on over a larger 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 surrounding the bushing sleeves of the chain and provided rolling contact with the teeth of the sprockets leading to excellent resistance to wear of both sprockets and chain as well. There is even suprisingly low friction, provided that the chain is definitely sufficiently lubricated. Constant, clean, lubrication of roller chains is certainly of main importance for efficient procedure and also correct tensioning