Abstract: A method of measuring the preload clearance in a double row rolling bearing. The double row rolling bearing includes an outer ring having outer raceways in double rows on its inner peripheral surface and first and second inner rings each having an inner raceway on its outer peripheral surface. Each of the first and second inner rings are provided concentric with the outer ring. The double row rolling bearing further includes a plurality of rolling members provided between the inner raceways and the outer raceways in double rows, respectively. The rolling members are preloaded when the first and second inner rings are abutted to each other at their inner end edges. The method includes the steps of obtaining the dimension H.sub.1 corresponding to the distance between the outer end faces of the pair of inner rings when the pair of inner rings are pressed lightly at their outer end faces in a direction to be closer to each other. Obtaining the dimension H.sub.

Abstract: A method of measuring the preload clearance in a double row rolling bearing. The method includes the steps of fixing the outer end face of the first inner ring in position while subjecting the outer end face of the second inner ring to a first load in a direction which moves the second inner ring toward the first inner ring at a relatively smaller constant amount so as not to reduce the preload clearance to zero, and obtaining a value H.sub.1 corresponding to the position of the outer end face of the second inner ring. Fixing the outer end face of the first inner ring in position while subjecting the outer end face of the second inner ring to a second load in a direction which moves the second inner ring toward the first inner ring at a relatively larger, constant amount enough to reduce the preload clearance to zero and obtaining the value H.sub.2 corresponding to the position of the outer end face of the second inner ring. Then calculating the difference between the value H.sub.1 and the value H.sub.