Bearing Clearances (including Miniature)

The bearing clearance is how much movement there is if you hold the outer ring still and move the inner ring up and down towards the outer ring.

A more technical definition: The radial play of a bearing is equal to the total radial displacement, in the median plane perpendicular to the bearing axis of the inner ring in relation to the outer ring, under the effect of a small measuring force.

Two things to keep in mind with regards to clearance:

1. The clearance is a range. It specifies the amount of play that is acceptable for
   any bearing with the clearance classification.
   
2. Clearance ranges overlap. This means that a bearing classified as C3, might
   also meet the criteria to be classified as CN. Another bearing classified as C3
   might also meet the criteria to be classified as C4.

The Clearance is a Range

A single bearing does not have a range of clearance. A single bearing has a clearance that is within the range. The range is the permitted tolerance for the clearance. To understand this, consider it like this. If you move the inner ring towards the outer ring in any given bearing, it will move as far as it can and then stop moving. Let’s say the bearing moved by 0.013mm. Now repeat the experiment on the same bearing using the same amount of force. The bearing will again move by 0.013mm. Nothing inside the bearing has changed to allow it to move any more or any less.

There is much more to this article in the PDF.

Download the Bearing Clearance Info Sheet PDF.

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