If your chain is really worn out or had a fair amount of wear, be careful, you may need to replace worn gears as well !!

I had this issue on my mountain bike, and basically a new chain is not streched and worn to fit the worn out gears, and the chain will slip off the gear under pressure. If you notice slippage there is a potentially serious problem. The result of this was a bad fall and looking at the exposed bone in my knee.

Anyway, a recumbent may not cause you to fall the same way a mountain bike can since your whole body weight is not on the pedal, but it could very well be a problem in other situations. The gears most likely to get worn, as far as I can remember, were the sprockets because they were small and the wear was not distributed over many teeth. Then again I may have replaced chainring or both sprokets and chainrings, can't quite remember.

I'm just saying, be careful cause its a safety thang !