void SET_VEHICLE_WHEEL_IS_POWERED(Vehicle vehicle, int wheelIndex, BOOL powered);
Sets whether the wheel is powered.
On all wheel drive cars this works to change which wheels receive power, but if a car's fDriveBiasFront doesn't send power to that wheel, it won't get power anyway. This can be fixed by changing the fDriveBiasFront with SET_VEHICLE_HANDLING_FLOAT.
Max number of wheels can be retrieved with the native GET_VEHICLE_NUMBER_OF_WHEELS.
This is a shortcut to a flag in SET_VEHICLE_WHEEL_FLAGS.