ISO 18808:2021 specifies the designation, dimensions, approved rim contours, load ratings and reference speeds for agricultural tyres fitted to construction machines (e.g. backhoe loaders, small dumpers, loaders, excavators) operating on building sites under loading and transport conditions.

Tyres conforming to this document are identified by the suffix IND in the tyre size designation; code designated tyres can alternatively, in place of the suffix IND, be identified by the classification code R-4.

NOTE Agricultural tyres without the suffix IND in the tyre size designation or with a classification code differing from "R-4" are not part of this document. Code designated diagonal tyres (ply rating marked series) for agricultural tractors, trailers and machines are part of ISO 4251-1 and ISO 4251-2. Code designated radial tyres for agricultural tractors, trailers and machines are part of ISO 8664. Metric designated tyres for agricultural tractors, trailers and machines are part of ISO 7867-2. Tyres for forestry machines, identified by suffix LS, or classification code LS-x are part of ISO 18807.