I installed mine without removing the tires with no trouble. I used these tools to remove the old rivets:

Amazon.com: Auto-Body Technician's Best Friend - No-Scratch Trim and Molding Removal Tool Kit Set: Home Improvement


And this to install the new rivets:

Amazon.com: Klik Plastic Rivet Setter with Pouch: Home Improvement

The rivets came with the fender flares. The entire job took less than 1 hour. There is a helpful post somewhere on this forum that includes step-by-step instructions with photos.

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2011 xDrive 35i Sport Activity/Black Sapphire/Tobacco/Technology Pkg/Convenience Pkg/Premium Audio/Heated Rear Seats/Tint/Running Boards/Black Grill