Cinelli quill stem

Hello again fellow cyclists

I have an early 1990s Peugeot Optimum which I feel a little too stretched out on, it's a 58cm frame (traditional old school geometry) with what I think is either a 100mm or even 110mm stem, I'm 6ft tall and most charts point me in the direction of a 58, I prefer the look of the older style bikes to that of the new sloping top tube and compact frames, I'm trying to tailor the fit so I'm a little bit more comfy by getting a 90mm Cinelli stem. I've run into a bit of a problem here because I'm unsure of the diameter of the quill, I've done a bit of research and found out the size of the Atax stem that came as standard on this model is a 22.2mm, does that sound right? I mean I've looked at the charts on the Cinelli site and nowhere does it seem to give you that measurement, it only seems to give measurements for the bar clamp diameter and the length.

Even more confusingly I've an older Atax stem that I think might date from the early '80s which is the perfect length but when I tried to fit it it seem ever so slightly thinner than the one already fitted to the bike; it wiggles around even with the race/nut and bolt all tightened up, I need some guidance, will a Cinelli stem fit the steerer on my Optimum? I don't want to end up buying one for it to do what the older Atax stem does.

Many thanks in advance

Re:

You're talking about the 1A right? AFAIK the 1A is for 1" threaded forks, so has a 22,2mm diameter.

But still I would look for alternatives as the 1A is too expensive in my opinion.

Hello sorry for the late reply, thanks for the the response, I did end up buying one after but I'm now wondering if the clamp would take the existing Atax bars that came fitted to the bike or will I have to change these as well. I've read that the clamp is 26mm and that older stems came with 26.4mm does that sound right?

Thank you

Re:

This is a standardisation story..

Afaik:

Once upon a time French bikes had steerers with an internal diameter of 22.0mm, (metric innit?) so period French stems (like your Atax) often have shafts of that diameter. At some point I guess the French resigned themselves to the Procrustean Bed and moved to 22.2mm.

Likewise, Once upon a time in Milan, Cinelli bars/stems were made with a diameter of 26.4mm for the mating parts, whereas over in Turin, TTT bars/stems had a diameter of 26.0mm. I guess at some point Cinelli resigned themselves to the Procrustean Bed and moved to 26.0mm..

Re:

Thanks for clearing that up for me, I'm starting to understand these sizes now.

It's a later Atax so it's after their shift over to more standard dimensions, the Cinelli stem will fit the steerer on the Peugeot but unsure it will take the bars I have at the moment, I think I might have made a mistake with the bar diameter, I think they may be 25.4 not 26.4 sorry. I've read somewhere that I can get something called a shim that'll fill the gap between the bars and the clamp taking them up to the 26.0mm needed.

Can anyone reccommend a good shim or is it worth me just spending the money on a good set of 26.0 handlebars.

You've correctly identified that most quill stems have a 22.2mm stem. Some older Atax stems were 22mm because French bikes were metric rather than simply converting imperial to mm.

Most British made stems and bars are 25.4mm at the clamp. Cinelli 1A stems came in 26mm and 26.4mm. You can use 25.4mm bars in a 26mm 1A if you use some shims. I *think* some of the older Atax bars were 25mm at the clamp, again, a French metric size. Mine are up in the loft though, so I can't check. What you shouldn't do is clamp down a bigger stem onto smaller bars until it's tight. The cast alloy doesn't like it at all and the clamping diameter will be mismatched, which makes for a poor hold in the stem and the bars will wobble and flex.

Velo Orange shims are very good. They're rough stainless and grip very well.

Folded coke can also works, it's just a bit of a bodge.

Re:

That's very informative, thanks for clearing that up for me about the sizes and for the tip off for Velo Orange. There's so much to learn