I'm looking for tire options for the Roadliner. The owner's manual says Bridgestone G850/1 or Dunlop D251. I can find prices for the Bridgestone however, I can't find the 190/60 17 rear tire for Dunlop or any other brand except Bridgestone. Did Dunlop quit making that size rear tire? Have any of you found any other brands? Is there another size rear tire I can use?