The multi-rib drum belt is also known as a drive belt and is a part for your dryer. The function of the drum belt is to attach to the motor pulley. It will then spin the drum as the motor rotates. Over time this part will naturally dry out. If your drum belt begins to crack or break, the dryer will not be able to continue to turn. If your dryer is running but your belt will not rotate, that likely means that it has been damaged and needs replacing. The tools you will need for this repair are a putty knife and a screwdriver set.