Brushless Rotor Size
 

Will going to a smaller rotor on a brushless motor give you more or less torque? What other differences does it make?

Using a smaller rotor will give you a little less torque, slightly higher revs overall and weaker brakes. Depending on the type of motor it can make the difference between undriveably lairy and smooth and controlled.

What it will also do is make the motor less efficient and more prone to overheating. You might have to adjust gearing to compensate for the lower torque and the heat.

Yep^^^

Cool, does anyone know the rotor diameter on X12 motors??

12.5mm comes as standard and you can get a 12mm and a 13mm as options.

What about the Speed Passion V3.0 rotor sizes, anybody know them?