[RC-Monster Mike]

You don't need the 22 series motor, either. The 1940 or 1950 series are both PLENTY of motor, and will run cooler than the Feigaos or basicxl motors due to their segmented magnets (ideal for less than full throttle currents like used in r/c land applications). These come standard with a 4mm shaft. i plan on getting some 4mm bore pinions made soon as well, as these high end motors seem to be catching on.