[skimoose]

We haven't run tests, but we had vex chain lifting 3 pounds of mini tetras on a two stage elevator that weighed another 3+ pounds. The vex chain is plenty strong. Most of the time when the chain parts or occasionally breaks it's due to shock loads or bad alignment of the sprockets causing uneven stress on one side of the chain. Shock loads like sudden starts or stops caused by sticky mechanisms or hitting a wall or robot, etc.

To test the chain strength fix one end of a length of vex chain to something solid connect the other end to a hanging fish scale and slowly pull on the fish scale until the chain parts. Repeat a few times and you'll have a good idea of how strong the vex chain is.