Trp TRP-42 Disc Rotors 203mm Silver RotorTRP 42 Disc Brake Rotor 203mm 6 Bolt 2. 3mm Thick Silver Black. The TRP 42 2 piece slotted 6 bolt thick disc rotor is designed specifically for use with select TRP DHR and E MTB brakes only. These rotors offer high heat dissipation due to the aluminum center as well as excellent stiffness to provide confidence in your braking. For DHR and E MTB only 2. 3mm thickness offers a lower temperature under braking and 50% reduction in rotor warping