Overloading causes the tire to wear the inside of the tread if all the suspension components are in good shape .....as in not enough camber bow.
Wear on the outside of the tires tread can be a toe problem as in a bent axle fore or aft.
One of my drivers reported sever wear pattern like that on a 34' GN trailer. On his reload run I crawled under neath for a check. I found both axles bent with big scrape marks on the bottom/center of the axle tubes. The driver had drug the trailer over a tall cement roadside devise hidden in weeds and bent both axles enough to cause severe outside tire wear.
A two hr trip to a big rig trailer repair shop to have the axles bent back in alignment got him back on the road.
Its odd that all 4 tires are wearing the same.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers
'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 two slides