Stem/handlebar compatibility

[PNW]

I have a set of Superleggera Deda carbon bars which state a 31.7 diameter...the stem that I have is a 31.8 Moots Ti stem. Will the stem work with these bars? I mounted them and they appear to be fine...

[BdaGhisallo]

No problem. The diameter is actually 1.25” which is 31.75mm. Deda, who were first with the oversized bars, marketed it as 31.7. Companies that followed chose to round it up and wentbwith 31.8.

[dddd]

It's funny to me how the industry repeats itself, here just as before with the former 25.8 vs. 26.0 stem clamps.

It's possibly just a way to try to keep the combinations of components within brand as actually-tested combinations that allow these companies to sleep at night.

Other things like the width of the clamping area, the degree to which the clamp spreads it's clamping force uniformly, and the degree of flexibility of the portion of the handlebar that the stem clamps onto, all of these other things can affect the results of testing for everything from slip resistance to metallurgical failure to unwanted noises.

So I think that it's these things, in addition to marketing (and selling) more product that leads manufacturers to choose a more or less proprietary clamping diameter specification.

That different company's clamping diameters are so close suggests that they don't want to totally prevent their products from being used in combination with other's products, but that they prefer that they are used together with their own other products for various reasons.

Of course I'm talking here only of the cases where just a .2mm difference exists on paper, not of the case where bigger differences exist.