The objective of this document is to restrict the number of radial bearing sizes just enough to ensure economic production, yet provide a sufficient number of sizes to satisfy present and future needs of bearing users.
These needs are comprehensive and varying. Therefore, this document needs to embrace a wide range of numerically determined sizes and proportions and can even be extended according to the guidelines given in Annex 
Tapered roller bearings, insert bearings and some types of needle roller bearings and instrument precision bearings standardized by ISO do not conform to this document because the dimensions given are not found to be optimal for the bearings in question.

The objective of this document is to restrict the number of radial bearing sizes just enough to ensure economic production, yet provide a sufficient number of sizes to satisfy present and future needs of bearing users.
These needs are comprehensive and varying. Therefore, this document needs to embrace a wide range of numerically determined sizes and proportions and can even be extended according to the guidelines given in Annex 
Tapered roller bearings, insert bearings and some types of needle roller bearings and instrument precision bearings standardized by ISO do not conform to this document because the dimensions given are not found to be optimal for the bearings in question.