-- If you go to the AndyMark site, they have CAD drawings of the wheel provided in the KOP. There is a cavity between the bearing support ring and the sprocket mounting bolt holes that is a weak point. We blew one out being defended (aka rammed) by other robots, and blew this ring out. We have reinforced this area with fiberglass strand and resin to fill this void. This only occurred on one of our center drive wheels, but this mod should take care of it. Great traction and light weight. As good as our modified wheelchair wheels that we have used in the past, and easier to mount sprockets. Hopefully, AndyMark will modify their mold to eliminate this problem for next year. By the way, we were still functional and competitive the rest of the match, and only noticed the damage when we got back to the pits. --