Place chuck roast in crockpot. Combine remaining ingredients in mixing bowl. Pour barbecue sauce mixture over chuck roast. Cover and cook on Low 8 to 10 hours or 4 to 5 hours on HIGH.
Remove chuck roast from crockpot and shred meat. Place shredded meat back in crockpot. Stir meat to evenly coat with sauce.
Spoon meat onto sandwich buns and top with additional barbecue sauce if desired.
Serves 12