Lay 8 foot long pipes side by side on a flat surface and fix in place so that they cannot move or turn.
Using a measuring tape and permanent marker, put a dot at four points (from the bottom of the poles) on each pole as follows: 49-1/4 inches; 56-5/8 inches; 88-1/4 inches; and 95-5/8 inches. (These are the points corresponding to the top and bottom for both men’s and women’s regulation height volleyball nets, according to Volleyball USA.)
Drill a hole all the way through the pipe at each marked point, (without shifting the pipes) so the bit comes out the other side.
Slide a closed eye bolt through each hole and attach washer (against the pole) and nut on the opposite side.
Stretch a vinyl cap over the top end of each pole, and temporarily set poles aside.
Place tires on a flat surface (such as a garage floor) and put a scrap piece of heavy plastic sheeting in the bottom of each tire to cover the opening so concrete will not spill out.
Mix concrete according to manufacture’s directions, and pour into each tire on top of the plastic, working it carefully into the insides of the tire to eliminate air pockets.
Stretch a vinyl end cap over the end of each of the 8-inch pipes and push them--cap end down--into the wet concrete until the pipe encounters the floor the tire is resting on.
Center the pipes in the tire and temporarily hold in place with duct tape, bungee cords or whatever works to hold them level, centered and firmly against the floor surface. (Keep concrete covered with damp cloths or plastic for about three days to cure.)
Assemble by placing the 8-foot poles inside the 8 inch pieces of pipe set in the tires. Attach the volleyball net to the top eyebolt and the second from the bottom for men’s games, or from the second from top and bottom eyebolts for women’s games. (Co-ed games use women’s settings.)