With a growing demand rotor is committing to a separate mountain bike crank line named rex the additional line with its own designation and design will help to clearly distinguish the rotor mtb from the road crank line the new rex mtb cranks are based on the same successful trinity drilling system technology as all rotor cranks which helps reduce weight and maximise stiffness manufactured by forge and cnc machining its 30mm axle makes rex2 the perfect weight to stiffness balance ava