I've never needed more than 12" wrench. Just aim the wheel into a wall so that the direction of loosening the freewheel will drive the wheel into the wall. Then hold one hand on the wheel to keep it vertical, place the other hand on the wall to steady yourself and just stand on the wrench. I may have to give a slight hop, but anyone over 150-lbs should be able to break the freewheel free with their weight.