The Chaya G-Force Alloy Grippy is a high-quality wheel built and designed with roller derby in mind at an affordable price. At the perfect size and hardness for roller derby (59mm.90A) this wheel benefits from a stiff aluminum hub which means there is no flex in the wheel resulting in increased power transfer and roll. The highlight of this wheel is the added urethane lip that ensures snappy lateral movement across the track as well as greater push in your strides. Chaya G-Force Alloy wheels are available in four different hardness - 90A. 92A. 94A. and 96A.