Most bearings have their references numbers carved on the surface of cconveyor roller bearing, but these often rub off over time and so it may be necessary to measure the bearing yourself,

it is necessary to measure bearings to choose the correct bearing model.

You can measure the dimensions of a bearing by using a vernier calliper or measuring accurately with a ruler. bearings will have a width, a bore size and an outer diameter.

Once you have calculated the dimensions of your bearing, you can use search tool on the internet to find the correct bearing.

There are three main types of bearing: conveyor roller bearings, ball bearings and spherical roller bearing.

Once you know the bearing you need based on size, you can then choose further options:

The bearing also has a seal either side of the bearing and this will be indicated by the suffix:

ZZ or 2Z = 2 Metal Seals 
2RS or DDU= 2 Rubber Seals

Additionally, bearings also have a clearance value. This provides the bearing room for expansion between the bearing races and will add a small amount of play between the two rings.

A larger clearance is required if a bearing is likely to get hot，which to reached its operating temperature.