The sizes can at times get confusing, when looking for a 3x8x4mm bearing it’s easy to stumble across something like a 4x8x3mm by accident. Here we will show you which number comes first, second and third when measuring. Our example Bearing is an 8x16x5mm. The first Number is the Inner Diameter (id). As shown below, this is the inner ring or as some people call it the shaft size or hole. In our example this is 8mm

How to measure bearingson a map

Imperial Bearings are also measured by the same method, for example 1/2″ x 3/4″ x 5/32” (id)  x (od)  x (W) This Rule of Measuring in this particular order is universal. Whether its for Fishing Reels, Skateboards, RC Cars, Engines etc.

How to measure bearingsMaths

How to measure bearingswith a protractor

Plaig Bearings have been put to the test since 2008, with over 500,000 bearings being sold in Australia and across the globe.

Linear Bearings are measured the same way as regular bearings, it can be a little confusing because the width is usually the largest part but refer to the below picture if you get stuck.

How to measure bearingswith a ruler

Now that you have the measurements you can use our search feature and type in the size for example “8x16x5″ to see the available options for that bearing.

Measuring Bearings can be simple but often you may see variations in the way that bearings are listed, there is a universal method that is used by most manufacturers and we will explain this in further detail. Vernier Calipers are the most accurate way to measure a Bearing, if you don’t have any handy then a ruler will give you a rough guide. Most calipers have 2 Jaws for measuring, as shown in the picture below, the “Outside Large Jaws” are used to measure the external diameter or outer diameter (Od), these are also used to measure Width. The “Inner small Jaws” are used to measure the internal diameter (id).