180 vs 203mm Rotors
Power, Modulation, Heat Capacity and Personality. Let’s look at some differences between 180 vs 203mm rotors (7″ and 8″).
Increasing the radius of the rotor increases the brake’s leverage ratio.
Using Magura HC rotos as an example we measure about 12.7mm of “usable” rotor / pad interface. Picking a point of reference halfway in the usable interface the we come up with a 180mm (7″) rotor at 83.65mm versus the 203mm (8″) at 95.15mm. The change in available leverage around 12%.