It is necessary to distinguish between the internal clearance of a bearing before it is mounted and the internal clearance  of  a  mounted  bearing  in  operation(working  clearance).  Because  the  rings  are  mounted  with interference or transition fit, the rings will expand or compress, the bearing’s initial clearance is always larger than the working clearance.

    If the bearing is mounted with recommended fit and runs under the normal condition, the normal group of initial  internal  clearance is appropriate to the bearing’s working clearance .  If  the inner and outer rings are mounted with interference fit  or the working temperature is higher or lower,  we can select  larger or smaller clearance value than the normal group.