If you bought them new, instructions should be there. Open them up so the rings have hardly any deflection.
@skids Thanks. It never occurred to me that such simple devices would have instructions. I did not buy them new, so I don't have the instructions and it doesn't look like they're available on their website. Do you know what the instructions say about how tight they should be? By your description, it sounds like it should be just slightly snug and not require very much force to install.