[nonother]

Our team's experience with using chain and sprocket for drive trains is that it is disasterous. The amount of tension present causes one of two problems. The first is the chains simply snap. This could probably be remedied with doubling up chains. The second scenario that is far more troubling is the chains loosen eventually and so the amount of tension is reduced. When the gears spin the amount of tension on each side of the gears is not equal and so the difference in tension then causes the chain to snap. This seems to happen even when doubling up. Bottom line - if the situation requires high torque or has a lot of stress on it avoid chain and sprockets.

On another note - gears are hardly impervious. I've seen them snap, which just confirms my belief they should have made them out of metal. So if there is going to be a lot of stress on the setup, double up all of the gears.