Moped Army

As far as I know, the springs just keep tension on the shoes to keep them in place and to keep them from rubbing when you aren't applying the brake. They don't actually provide any of the stopping power -- all of that comes from the friction between the outside of the brake shoes and the inside of the drum. You can certainly replace them -- all of the new brake shoes I've bought have come with new springs -- but that wouldn't be the first thing I would replace if I wanted to stop better.