There are two types of links alternating in the bush roller chain. The first type is internal 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 external plates held with each other by pins moving through the bushings of the internal links. The “bushingless” roller chain is comparable in procedure though not in construction; instead of separate bushings or sleeves keeping the inner 
plates collectively, the plate includes 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 compared to simpler designs, resulting in 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 teeth; however this configuration exhibited extremely rapid wear 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 holding the outer plates passing through bushings or sleeves connecting the inner plates. This distributed the put on over a greater area; however the the teeth of the sprockets still wore quicker 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 put on of both sprockets and chain aswell. There is even very low friction, so long as the chain is sufficiently lubricated. Continuous, clean, Leaf Chain lubrication of roller chains can be of principal importance for efficient operation along with correct tensioning.