Originally Posted by SoonerBent
Shimano's instuctions say their bar-cons fit 19 to 22 mm bars. I can't inagine that .2mm would make that much difference.
22.2mm (for "MTB" bars) or 23.8mm (for "road" bars) is the outside diameter where the levers are mounted. Though they don't state it in the specs you linked to, Shimano is referring to the inside diameter.
For reference, one of my drop bars had an inside diameter of 20.6mm, and a different drop bar measured 21.1mm.