Jerry,
The XA is a later model that effectively replaced the 1-R as Cinelli's top- of-the-line stem in the late 1980's (1988?). It looks similar to the 1-R in that the handlebar binder is not visibly obvious when viewed from the f ront, or even the side, and in that it had a black plastic flying C logo "m edallion" set in a hole in the front. Mechanically it was far more sim ple than the 1-R. The front of the stem wrapped around the bar, and the binder went up through this tab and up into a threaded (8mm x 1.25mm IIRC ) socket in the stem extension. There were little colored rubbery pieces th at fit into the slit between the tap and extension. The only problem I saw with the XA was the the tab could bottom against the extension, even with the correct 26.4mm size bar. The XA was compatible with various kn urlings as well as the later Cinellis that were essentially unknurled oth er that two very narrow cosmetic bands. I did have one XA that fai led with a fracture from the hole in the front across to the outer edge of the st em. Back to Nashbar for a replacement. There is a later version of the XA with cheesier hardware, including a wedge binder rather than a plug, an d a bubbly looking front badge. They're pretty lame looking, and date fr om a time in the 1990s when this model was no longer top-of-the-line for Ci nelli. The 1-E came out around then too. It was a cheapened version of the 1-A that often shows up on Ebay as a 1-A. It's more of an OEM of fering.
Overall the XA was a step back toward practicality from the 1-R, but it sti ll was less practcal than the old 1-A, which I've never seen with the botto ming problem seen on some XAs. Also, the entire handlebar binder (male and female parts) of the 1-A was replaceable (while somewhat prone to cr acking). The XA relied on a threaded boring in the alloy forging, which could strip, theoretically, though I have never seen it happen. If it di d the stem would essentially be scrap. Anyway, I've seen cracked 1-Rs and XAs, but never a cracked 1-A, that I can recall, and I've probably see n far more 1-As than 1-Rs and XAs combined.
In the mid 1980s there was a stem called the X-R, or something like that. It was a short-lived attempt to address the "issues" with the 1-R. I t appeared to be made from the same basic forging, and had what you might c all a closed topology. There was no throughgoing slit at the handlebar c lamp. There was a long horizontal slit behind the bar in the middle of t he extension that was releived at the end by a larger radius boring paralle l with the bar. The handlebar binder came up through the bottom of the e xtension slightly behind the bar, across the slit, and into a threaded sock et in the upper half of the stem extension. The slit and the holes at th e rear end of the slit were filled in with colored rubbery insterts, precur sor to those on the XA. I think there is some info on this stem on the C R website. It came out at the time of the hexagonal EXA bar, yet another impractical idea from Cinelli, which may have had it's last good idea in t he early 60's.... but a you still have to love them.
I'd love to have one of these oddball intermediate stems in 125-130mm for m y collection. I've only seen perhaps two in the flesh. I don't know th at they were ever even brought to the US, and I don't recall the Cinelli-su pplied teams ever using them. Rare-but-not-sought-after....
Tom Dalton
Bethlehem, Pennsylvania, USA