It looks like you will need to have your current brackets removed and have new ones welded on since none of the landing gear sets we offer are designed for brackets that are 15 inches apart. Any qualified welder could do this for you and would not be a big deal.
The two sizes we offer are for 17-1/2 inches between the brackets like the Reese/Bulldog part # RP500708 or 20-1/4 inches apart like the Ultra-Fab # UF17-943010 . view full answer...