Dave-
Thank you for your question. The Husky Liners Custom Molded Mud Guards are designed to fit on the rear nacelles of the Dodge 3500 dually. To fit your 2011 1500 Big horn you might consider the weather tech mud flaps found here http://jo.my/u2uw88. They will fit against the rear edge of the wheel well and will clear the factory 20" wheels.