An anonymous poster wrote:
> Hi if I am not mistaken.... MTB stem clamps are 25.4mm dia.=20
Yes, that is the ISO standard size for all types of bicycles, a.k.a. 1 in=
ch.
> Roadbike
> quill stems used to be the same but when changed to threadless system
> went to a 26.0mm dia. clamp.=20
No, there's no connection with threadless, that has to do with the other =
end of the stem, the way it fits on the fork.
Both quill and threadless stems are readily available in both 25.4 and=20
26 mm sizes. The selection is much better, however, in the ISO=20
standard 25.4 size.
Before the ISO standards were promulgated, there were a variety of=20
national sizes for handlebar/stem clamps, and also some proprietary ones =
used by specific manufacturers (Cinelli, Titan.)
Because some Italian brands of stems and handlebars were popular for=20
high-end road bikes, the Italian 26.0 mm standard is often used as a=20
secondary size standard for drop handlebars, but most drop bars on the=20
road are actually 25.4.
> They are now doing 31.8mm dia clamps which are indicated as oversized.
a.k.a. 1 1/8"
Sheldon "Can't Kill Inch-based Standards" Brown
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