Bedtime stem size worry
09-25-11, 04:56 PM
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Bedtime stem size worry
Well I started my last thread with some disclaimers and an apology and I am afraid I am going to do that again. I have searched for hours online to find an answer to this because I think it may be a stupid question and I did not want to bother you folks with it, but I am still non the wiser. Please can you help? I have an old Reynolds 531 bike frame and I have two handlebar stems that fit it. One of them is pretty the other nasty. But I want to get some new bars (Nitto B123 orB125) The pretty stem is Cinelli and has a 26.4 clamp size, which I could shim but perhaps as the gap is so large it would be nice to get a new stem and sell the old ones.
My trouble is I can’t really tell what diameter the stem itself is. My searches online have said that the smallest standard size is 1” but my stem is smaller. I have some very technical callipers that I find difficult to use and on those the current stems seem to be about 22.5 mm (a little less than 0.9 inch). Just to be extra clear, this is the tube that fits into the frame size, not the clamp size. Is this an old size of stem? or have I got the whole thing wrong? I was thinking that it couldn’t be too unusual as I have two of these stems. Do you know what the official size of this stem is and could I get one to fit the 24.4 Nitto bars? I have see quills that are advertised as ‘22.2mm (standard 1")’ but 22.2 mm is not equal to 1 inch, and my measuring skills may be poor but I don’t think my stem is as small as 22.2. I am feeling a bit tired now so I could be wrong. Most search results end up talking about clamp size. Few want to talk about stem diameter. Is this a conspiracy? I am pretty certain I am being dumb and missing something obvious here. Perhaps I should just risk getting the standard 1” but I want to be sure.
Sorry if this is an old question that has been asked before. After much searching I can’t find it on this forum either and I must go to bed some time tonight. Thank you if you are willing to help.
My trouble is I can’t really tell what diameter the stem itself is. My searches online have said that the smallest standard size is 1” but my stem is smaller. I have some very technical callipers that I find difficult to use and on those the current stems seem to be about 22.5 mm (a little less than 0.9 inch). Just to be extra clear, this is the tube that fits into the frame size, not the clamp size. Is this an old size of stem? or have I got the whole thing wrong? I was thinking that it couldn’t be too unusual as I have two of these stems. Do you know what the official size of this stem is and could I get one to fit the 24.4 Nitto bars? I have see quills that are advertised as ‘22.2mm (standard 1")’ but 22.2 mm is not equal to 1 inch, and my measuring skills may be poor but I don’t think my stem is as small as 22.2. I am feeling a bit tired now so I could be wrong. Most search results end up talking about clamp size. Few want to talk about stem diameter. Is this a conspiracy? I am pretty certain I am being dumb and missing something obvious here. Perhaps I should just risk getting the standard 1” but I want to be sure.
Sorry if this is an old question that has been asked before. After much searching I can’t find it on this forum either and I must go to bed some time tonight. Thank you if you are willing to help.
09-25-11, 05:55 PM
#2
Dolce far niente
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Refer to the chart, and all will be revealed:
https://sheldonbrown.com/handsup.html
22.2mm is the Inner Diameter of the 1" (25.4mm) steerer tube, were you insert the stem. So, the stem has to be 22.2mm in diameter to fit.
That's pretty much standard, except the French. But no one cares about them any more.
Clamp size is the clamp where you insert the bars into the stem. Different deal.
https://sheldonbrown.com/handsup.html
22.2mm is the Inner Diameter of the 1" (25.4mm) steerer tube, were you insert the stem. So, the stem has to be 22.2mm in diameter to fit.
That's pretty much standard, except the French. But no one cares about them any more.
Clamp size is the clamp where you insert the bars into the stem. Different deal.
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09-25-11, 06:07 PM
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In addition, Cinelli stems at 26.4 really only work well for Cinelli bars of similar vintage, which are sized at 26.4. Modern available bars are 26.0. Different, and some may say it's an ok difference, while others will not. Used Cinelli bars at 26.4 are not hard to find. I believe the HB clamp will close down far enough for 26.0, but consider that it IS a 25+ year old stem, and a breakage could be hazardous. I would stick to matched sizes myself, just because I don't like to chance mismatches when it really won't cost much to avoid the mismatch.
There were also some rare Ambrosio bars that are sized for Cinelli stems. Most Ambrosios, however, are not. You'll need to use that caliper.
Regarding the search v. asking issue, no worries, and I feel your pain. Personally, I don't mind seeing the same question over and over - some essential things are not said enough, and are hard to find. Now you SHOULD sit down with a spare afternoon and peruse Sheldon's site from cover to cover, just to be familiar with what's there and to know how to navigate it.
There were also some rare Ambrosio bars that are sized for Cinelli stems. Most Ambrosios, however, are not. You'll need to use that caliper.
Regarding the search v. asking issue, no worries, and I feel your pain. Personally, I don't mind seeing the same question over and over - some essential things are not said enough, and are hard to find. Now you SHOULD sit down with a spare afternoon and peruse Sheldon's site from cover to cover, just to be familiar with what's there and to know how to navigate it.
09-25-11, 06:45 PM
#4
Disraeli Gears
+1 on 26.4 dia. bars not being that hard to find. I have two (identical) Ambrosio bars from an eBay seller in England, neither ever used, and they both have 26.4 barrel diameter. I believe that Cinelli manufactured that size stem/bar until sometime in the 90s -- meaning that there are still a lot of them around, both bars and stems.
09-26-11, 02:59 PM
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Thank you everyone. I was a bit too tired to search last night and I was going around in circles. Your comments have really helped, although I am still a little unsure, but I will try and get my head around it. I guess mine is the standard 1". I don't yet understand the terms on Sheldon Brown's chart but I will take Road Fans advice and study the whole site at the weekend. Thanks bigbossman I now understand the measurements refer to different things. Thanks Charles I took your advice and looked for old cinellis. You are right there are some nice ones out there; you may have saved me a lot of cash. Thanks again.
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