Tall grain sides require chain stiffeners inside to keep the sides from bulging out. Not that you will haul 250 bushels... just saying... we had sides like 78Buckshot's... 1 chain for the low sides and another for the slip-on top sides.
They made themselves handy for climbing inside with the bed raised to get all the grain out too.
You are correct,my grain box still has 3 chains, I haven't had any grain in her but did have 110 bales of hay a few times.
