They flex fine. No binding. When I glued them I held them flexxed down, glued one side, flexed it the other way and turned it over and glued the other. 15 minutes later, I was tugging on them, and it held just fine, and was able to move them freely. It just seems not to have a lot of throw in them. About 3/4 to 1 inche up and 1 to 1.5 inches down equally on both sides.