[jsr]

Motors can be picky. Overgearing (too short) and undergearing (too tall) will both overheat a motor, dropping efficiency, which causes more current draw, which further drops efficiency...it's a viscious circle once it gets started. The HW motors are low-cost entry-level motors. For their price, they perform well. Obviously not as good as the higher-end motors, but those cost a LOT more. At least the HW motors have captured screwed-in endbells instead of press-fit (which even higher end motors use).