The new 6-bolt RT-6B750 rotor is more robust than its predecessor and delivers more power, more consistently. Increased durability comes from the rotor&';s 2.2 mm thickness, a feature added to the model in response to market demand, and one that will extend the rotor&';s life over that of a standard 1.75 mm rotor. The new model also marks a change in rotor diameter: The longtime 203 mm spec shrinks slightly to 200 mm for the first time-a change that other Shimano rotors will follow in the future-while the 220 mm spec touts the highest braking power available in the lineup.