Originally Posted by
zzyzx_xyzzy
Note, when you say "the same as a 26mm bar," you mean to say "23.8mm."
Drop bars, noodle bars, aerobars, triathlon bars are usually 23.8mm where the brakes and grips go, and either 26.0 or 31.8 at the stem clamp. (though some have 25.4 clamp size)
Flat bars, riser bars, north road bars, cruiser bars and butterfly trekking bars are usually 22.2 where the brakes and grips clamp on, and either 25.4mm or 31.8mm at the stem.
If only one dimension is quoted for a bar, it's the stem clamp size. They expect you to know that bars that curve down or forward are 23.8 and bars that curve up, back, or flat are 22.2.
Actually, what I guess I could have said is that "the rest of the handlebar will have the same diameter for clamping brake levers as a 26mm stem clamp diameter handlebar will have." I've never seen handlebars referred to by anything but their stem clamp diameter so that's the terminology I was talking in. I just didn't do the best job of making that perfectly clear as you pointed out
