An axle center for the forward axle in a vehicle having tandem drive axles includes a housing containing input, output and through shafts that rotate in the housing about a common axis on front, rear and through shaft antifriction bearings. The front and rear bearings, which support the input and output shafts, are mounted in opposition. The front bearing has an outer race provided with an external thread that engages an internal thread within the housing. That outer race is fitted with a locking ring provided with an inner flange that is engaged to turn the race and thereby bring the front and rear bearings into the correct adjustment. The locking ring also has an outer flange which is engaged with the housing once the front and rear bearings are correctly adjusted so as to maintain the correct adjustment.