Internal bearing clearance is a product of the stack up of internal component geometrics. This measures the free movement within the ball bearing, sometimes referred to as ‘play’ or ‘slop’.
This directly impacts bearing performance and, eventually, bearing life; a reduced clearance can increase heat generation, whilst an increased clearance can create unwanted vibrations. Bearing internal clearance must be made with careful consideration in order to maximise its performance.
Using ball selection to achieve the desired internal clearance is the most common method of achieving this, but some manufacturers standardise the ball size and match the bearing races instead. Internal clearance uses the measure of displacement of the inner and outer rings respective to each other, in both the radial and axial directions.