Check the tires for cracks on the inside sidewalls. I have seen tires where the outside sidewalls looked good yet unbelievable how bad inside sidewalls were cracked.
Looking at the rear and seeing the chains midway on the inside of the side racks has chains just as on my son's grain bed. Those chains were there to keep the bedsides from bowing out too much when loaded with grain.
If there was the rear rack the middle third of it would have a small door through which the grain would be poured out of. I believe they are called coal doors.
