Double pitch roller chains
Double pitch chains are based on the single pitch chains constructed according to ISO 606; except for the pitch, they meet the same standard specifications with respect to their dimensions. As opposed to short pitch chains constructed to standard ISO 606, these chains are intended for use in conditions in which demands on speed and power transmission are lower.
The principle difference being that the plates of double pitch roller chains – as the name implies – are twice the length of the plates fitted to standard roller chains.