Mario F : Will it work on handlebars that are 26-29 mm???LAWRENCE D : It may work if you can find shims to take up the space, otherwise no the clamp will only fit the larger diameter bars.FRAN C : Gave it as a present to a buddy who was biking across America this summer. It fit my diamondback road bike carbon handle bars.WALTER M : There are several sizes. You want to buy the closest size to your bar as they are meant to fit rather precisely.John V : I have shimmed them up with cardboard, a sub-optimal solution.BING G : You need shims.