I decided to write this manual after I realized this is the main problem Boat, Horse and Utility Trailer owners are dealing with.
Then I started an extensive research with my own local repair customers and my online parts store clients to understand what are the most burning questions they have regarding trailer Hubs, I then kept investigating on all the search engines (Google, Bing, Amazon...) on what people of the internet are interested to know.    
I really want to know if it helped you,                       and let me know.