How to install brakes with clamps that are too tight

Question

I recently picked up a set of Avid DB1's and put them on my bike, but it was a bear to get them on. For background, they've got a split clamp that is similar to a seat tube where simple compression keeps it in place versus a two-piece clamp that requires more than one screw to tighten.

What I found was that the clamp, even when loosened all the way, would not slide down the handlebar and I had to shimmy it back and forth to move them further in, which ended up scratching and removing a large amount of paint (it's ok, that part goes under the grips). But this doesn't seem right to me. Is there:

1. a better way to install them?
2. different handlebar diameters that would complicate installation?
3. something else I totally missed?

Answer 1

A general procedure with too tight clamps: Put in the screw or a longer one of the same diameter from the opposite side. Fit a piece of (hard, like a small coin) metal into the slot. Tighten the screw carefully. It should open the clamp enough to fit it over the bar