I had this recently,if you have a thin yellow space saver you need a different screw type wingnut thats in the picture.you can do that one up all the way and it wont securely hold the tyre down.basically if thiisis the case you need the wingnut screw which has the wingnut part around 2cms down from the top which is jap spec i suspect and has a thread going out the top for the black part pictured which then holds down the cardboard