How to Identify Bearings by Bearing Number - Calculation and
Fig! 3 – Series (Toughness) of Bearing! Thus, we can identify now that in case of bearing 6305ZZ, the second digit ‘ 3 ‘ means the bearing is of medium toughness! Bore size of Bearing! The third and fourth digit of bearing patter number indicates the bore size of bearing! It is the inner diameter of the bearing and measured in millimeters!