STI brifters on drop bars? Chicken Little is right. The clamp attachment is a 5 mm allen key under the hoods but outside the levers. There is a groove for the wrench on the outside of the lever that you'll see when you roll back the hoods from the front. You may need a special allen wrench to tighten it, since it takes a long reach to reach the bolt, and then you need a longish L shape to torque it adequately. It's a pretty hefty bolt - no danger of stripping it.