Low Heat (Recommended for Most Tender Results): Boneless Country Style Ribs: Approximately 6 to 8 hours on low heat. Bone-In Country Style Ribs: Approximately 7 to 9 hours on low heat. High Heat (Faster Cooking, Less Tender): Boneless Country Style Ribs: Approximately 3 to 4 hours on high heat. Bone-In Country Style Ribs: Approximately 4 to 5 hours on high heat.