Am adding a hitch to the draw bar on the back of my Kubota B3200. But every time I have gone by the "trailering" section at TSC or my car parts places, the balls mount with a larger diameter fitting than present on my drawbar ! I have seen lots of ball hitches on tractors, don't they just bolt on like my car/ truck ball but of a smaller diameter? Where do I find the 2"ball to fit my drawbar?