Oct 1, 2013

Bearing Measurements

So you’ve decided that you’re tired of paying twice the cost for a low quality bearing just because it has a brand name on it and are ready to venture in the world of buying your bearings by size and in a tad higher quantity.  You find your favorite bearing website and are a bit stumped on what all the numbers and measurements mean.  It’s not as complicated as it sounds and all you need to measure accurately is a precise metric ruler or a set of dial calipers.

First number is the inside diameter measurement of the bearing, aka ID.  In this picture we’re looking at an ID of 8mm.

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Second measurement is the outside diameter measurement, aka OD, of the bearing.  In this picture this bearing has an OD of 16mm

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Third and final measurement is the width of the bearing.  This bearing has a width of 5mm.

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This bearing would be cataloged on most sites as a 8x16x5 metric bearing.  Now there could be the exact same measurements on a bearing that had a small flange on the OD to keep it from being pressed all the way through a hole.  This is called flange bearing and is measured the same way.  Hope this helps answer any bearing measurement questions! – Nick