I used 3" 'C' channel (bolted in the middle), to form a cross. drilled 1/2" holes in the ends of the 'C', used 4" bolts to press down the lock ring. I tried 1 bolt in the center to pull down the cross to press the 'lock ring' down, but found out the 4 bolts through the 'lug' holes works best. It only has to go down about 1/4". MAKE SURE YOU REMOVE THE CENTER OF THE VALVE, TO LET ALL THE AIR OUT!!!!!!!!!!!!!!!!!!!! My,.02.