First things first, lets not work harder than we need to... 

Has your bearing got a part number hidden on it? 
You may need to gently clear the around the outer race of the bearing to find it. Even after many years of dealing with bearings, even the best of us can easily miss the reference if we do not look closely enough, it might be worth checking with a magnifying glass if you have one. 
 
Found it? 
Perfect, just type it into the search box on our home page. 
Okay, so its part number is missing or worn away. No Problem, ideally you will have a Vernier, but a good ruler will probably work, just fine. 
 
All you need to measure is the Inside Diameter, the Outside Diameter and the Width: 
 
Got them, Great! 
Now use the dimension search box on our homepage to find the replacement you need!