Cuz you can eyeball it. It comes with a flat bar. It's oversized or it's mountain diameter. No way it's 26.0.
Riser, whatever.
BTW, your flat bar levers are A) not gonna fit over bullhorns. B) gonna look stupid if you try to kludge it.
chucksbikes is giving these away right now:
http://www.chucksbikes.com/store/br001.htm