Wiring bias
From FIRSTwiki
The difference in motor performance when run clockwise and counterclockwise. It is called wiring bias because the difference is usally created by wrapping the windings on the armature angled in a particular direction. This is used in many DC motors in applications where the motor is only run in one direction, or is required to ouput greater power in one direction, a common example being portable drill motors being more powerful in the clockwise (drilling and driving) direction, not counterclockwise.

