My 2007 Bighorn came with a tire name I did not recognize (Karrier). For the past several months, I have followed the discussions on tire problems many Heartland owners have been having with the tires provided buy the manufacturer. I figured they were the exception. My tires were made in June 2006 and had less than 8000 miles on them. They were properly inflated, never exposed to the sun for long periods of time, no bruises or bumps, and visually checked for any signs of wear or fatigue just prior to my trip on June 1, 2010. The 5vr was within weight limits. On June 9th while decending a 6% grade in Oregon at 45mph, one of the drivers side tires blew. I managed to get the rig to the shoulder and had ERS put on the spare. I drove slowly 30 miles to the next tire dealer and had four new G14 tires installed. Upon checking the flat tire, I noticed a 6" slit on the inside sidewall, apparently where it initially blew. I am now convinced these tires are junk and I would highly recommend, like others before me, that if you suspect your tires are of an inferior quality, dump them, regardless of how good they look.