I'm not sure the stresses on a trailer are less than a truck... Many 8-lug trailers haul in excess of 20,000lb. I know they are tandems and duals, but the weight is still there. The side-loads while cornering will be little different than the rear wheels of the truck, and the fronts would only be much higher if you are throwing your truck into the corners doing a slalom course. I would suspect an upgraded suspension would be in place if that was the case.
Example: a tandem axle, single wheel trailer hauling a 1954 3/4ton on the deck. The loads on those wheels would be the same as the load on the truck wheels if it was carrying the trailer!

Current fleet (subject to change w/o notice)
\'49 GMC 3/4-Ton , 60 Austin Healey Frog-eye Sprite (some assembly required), 2011 Dodge Avenger, 2015 Jeep Cherokee. No, they don't all run.
My other ride is a (B737)no, (B767)no, A320.... Update... was Embraer E190, now Boeing B787.

Knowledge is a wonderful thing, but ignorance means you don't know you can't do something.