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.


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


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


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