A huband-spoke assembly is fixed to each end of the central axle using three small bolts through the hub, and the spokes are aligned with each other before being fixed in place with
these small bolts. The grenades are moved to different distances along the spokes but always in a symmetric manner; any asymmetry between grenade positions on opposing hubs could cause the spiderwheel to turn and eventually collide with the ramp. Once the grenades were fitted, additional bolts were added at the ends of the spokes as a safety precaution to prevent the grenades from flying off if the plastic holding screws were to fail.