I've got a set of Nitto RB-018 bullhorns with a center clamp diameter of 26mm. I'm also trying to find a cyclocross lever that will fit these bars, however, the diameter gets noticeably smaller after the stem clamp area, which means it's less than 26mm, I just don't know how much. I've done a string circumference to diameter approximation which gave me ~25.15mm, while my eye and ruler test gave me something just under 24mm. Anybody know the diameter of the bars at the grip area? P.S. I don't have one of those diameter tool thingies.

Also, I googled the subject and found a picture of an interesting looking set of levers.
brakesgm9.jpg
These look quite interesting, but I don't know what they are called. They're so interesting that I might buy a pair even if they don't fit!

Anyways, if someone could chime in it'd be much appreciated.
Thanks.