Many mountain bikers are discovering the difference a more powerful set of brakes can make on any bike, from XC to Enduro. While frame designs and mounting configurations usually dictate the largest rotor a bike or fork can handle, adapters may be available to size rotors up or down based on rider preference.
For this survey, please answer based on the mountain bike you ride most often.
Are you running a crazy configuration like 140mm rotors on a DH bike, or have you found a way to put 203s on a lightweight XC race machine? Tell us about it in the comments!