I'm going to be installing a new rotor on the rear of our tandem, replacing the current Avid 203mm. It's probably time after 8000 miles. I just wanted to post a note about the torque required: I believe the Avid rotors are 7-9 Nm. The Shimano rotor is 2-4 Nm. I'm guessing this is due to the much greater coefficient of expansion of Al versus steel? Wouldn't mind hearing from anyone who has installed these rotors.