Chain In depth

How it started

Swiss engineer Hans Renold came to England in 1873. In 1880 he invented & patented the bush roller chain.

Previously chain was only made up of pins and plates and all the load was carried between the pin and the plates. The introduction of the bush ensures the load was carried all along the light grey area giving a much longer chain life.Long chain life remains key objective of quality chain manufacturers.


Today, Renold Chain has a multitude of innovative features to cope with the most demanding operating environments. 

Development and refinement of manufacturing processes such as surface finishing and heat treatment along with the use of high quality steel has brought further substantial improvements to chain life. New designs are still being introduced to improve the wear life of Renold Chain.

Transmission Chain Components


exploded view of all roller chain components


Journal bearings

Chain is a series of journal bearings joined together, by side plates. This bearing is where the chain wear occurs and where lubrication is needed.



Rollers can either be curled (i.e. made from sheet curled round) or be solid (made from bar and extruded). Solid rollers give improved resistance to shock loading and fatigue. Curled rollers are normally more concentric but are sometimes forced to open under heavy load.


Bushes, as with rollers, can be either curled or solid with the same benefits and drawbacks as a roller. Normally heat treated to improve wear, and sometimes coned to make the bore parallel when pushed with an interference fit into the inner plates.



Plates are normally waisted. The thicker the waist normally the better the load bearing characteristics. Renold plates have a unique shape and precise holes to give extra long life. Normally heat treated to improve performance and sometimes shot peened to improve fatigue resistance. The hole quality is important for longer life.


Pins are normally ground to give a smooth surface for improved wear. They are “through hardened” for resistance to heavy loading or “case hardened” for a hard surface finish but a softer more flexible core. Riveted after fixing through the outer plate. Renold chains have softened ends to make disassembly of the chain easy.


When the first three components are assembled, this becomes the inner link.


The final part of the chain assembly is the outer link.


Simplex, duplex and triplex variations are common. Up to decaplex (10 strands) is available:



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