I don't understand why tube manufacturers still make tubes with the stem pointing towards the fixed center of the rim. Most discs don't have a hole because it wouldn't be possible to put one in there. If the center of the rim was gone everything would work fine. However, the rim centers of small general purpose tires are usually equidistant from the front and rear. It would be great if camera manufacturers pointed the flap slightly off-center in one direction. In my case the valve seems to be pinched to fit through the hole. Used on Troy Bilt cultivators.