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, comprising two external plates held jointly by pins moving 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. This 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 Auto Chain initial power transmission chain varieties lacked rollers and bushings, with both the inner and outer plates kept by pins which straight contacted the sprocket teeth; however this configuration exhibited extremely rapid put on 
of both sprocket tooth, and the plates where they pivoted on the pins. This issue was partially solved by the development of bushed chains, with the pins holding the outer plates passing through bushings or sleeves linking the internal plates. This distributed the put on over a larger 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 encircling 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, so long as the chain is certainly sufficiently lubricated. Continuous, clean, lubrication of roller chains is of principal importance for efficient procedure and also correct tensioning.