Anonymous wrote an answer about Yakima KingPin 4 on June 26, 2012
It is stable on my 1.25-inch hitch. Also, you don't need to buy the converter for this part because there is a removable sleeve that allows it for use with a 2-in hitch. Remove the sleeve and it will fit 1.25-in hitch. Your 1.25-in hitch should also be class-2 so that the male end will slide all the way into the receiver. Otherwise, you will need to "modify" the male end to fit into a class-1 hitch.