I felt the need to use a "spider mount" to support the rear of the gearbox. If you plan to 3D this motor with a large prop ,the front mount or a cage mount with the rear spider mount would be recommended. The torque imparted from a large 3D prop and the stressful gyrations we sometimes put our planes thru(who me?) can do bad things to a front (spider) mount. Just a word of caution for those hardcore 3D folks who want to try these motors. My 2 cents.