Sorry for the multiple messages. Can only send messages with no more than 1000 characters.
See this link. It has a chart showing pictures of trailer tire wear and what they mean:
Look at the one side wear which is happening on the front axle and the other axle has tire cupping.
http://www.google.ca/url?sa=t&rct=j&...48705608,d.bGE
Cheers
Pat