Conquer the hills with the super low 34t gear on this megarange tz31 7 speed freewheel a reliable 7 speed screw on freewheel the shimano megarange system gives you a super low 34t gear to help you tackle steep hills with ease engineered for smooth chain movement up or down the block for 7 speed gear systems can be easily installed onto compatible screw on type hub suitable for mountain bikes and a wide range of other cycles