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21.1 stem options for dirt drip mtb conversion

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21.1 stem options for dirt drip mtb conversion

Old 09-24-21, 12:20 AM
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21.1 stem options for dirt drip mtb conversion

I'm just considering it for the moment. My '86 Ross Mt Hood has a 21.1 threaded headset/stem and I'm actively searching for quill stems 'cause I"m gonna need a tall one to make it happen. I've seen the chrome steel sunlite versions and the like, but I'd rather go aluminum, if possible. IF that exists! So far, I"m not seeing any, but maybe someone knows if there is something? I'm not opposed to steel so you know, but those sunlite ones look a little too ....mmm...dept. store/murray/huffy like, if you know what I mean. Wald has the same type, btw

Failing a decent and appropriate stem, anyone ever reamed out a 21.1 steerer to 22.2? OR, modified a 22.2 quill to fit? OR, maybe go half way on each....the steerer and a stem?

FYI, I'd like to go in the Cunningham'esque tradition, to give you an idea (Cunningham roller cams and all that). I've wanted something like it for forever, and this seems like a good candidate. Maybe it's a stupid idea, but ya never know until you ask around sometimes.....
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Old 09-24-21, 12:32 AM
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something like this would be super if it were taller.....

https://www.ebay.com/itm/284221217099

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Old 09-24-21, 12:46 AM
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HMMMMM!!!! I may have found it......https://www.xxcycle.com/stem-humpert...211-mm,,en.php


It'd be quite similar/reminiscent of the original Ross stem with the steel insert and black alloy extension. Still open to other options anyone may know of. Again, something like the Promax above would be great if there's taller ones?
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Old 09-24-21, 02:48 AM
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Humbert Dino-X 21.1mm / .830" Stem

Originally Posted by thook
HMMMMM!!!! I may have found it......https://www.xxcycle.com/stem-humpert...211-mm,,en.php

It'd be quite similar/reminiscent of the original Ross stem with the steel insert and black alloy extension. Still open to other options anyone may know of. Again, something like the Promax above would be great if there's taller ones?
Being unfamiliar with MTB and BMX stems and forks from that era, what's the outside diameter of the steerers that take a 21.1mm / .830" stem?

Easiest way to tell is what's the thread size of the headsets?

If it's 1", the steerer can be bored out to 22.2mm on a mill or a lathe. Trying to ream out 1.1mm is a LOT of work. Reamers are intended to remove a much smaller amount of material to accurately size a bore.

The fork would need to be rigidly fixtured on either a mill or lathe while boring it out, otherwise the cutting tool can easily grab inside the bore and you have a mess! (Been there - done that).

Several other things: the bore should have a taper at the bottom of the resized area rather than a sharp shoulder to reduce the possibility of a stress riser and... make sure that the expander wedge is below the threaded area of the steerer. 75mm to 80mm is the recommended minimum amount of insertion for the stem into the steerer.


There are a number of European websites that list the Humbert Dino-X 21.1mm / .830" Stems pictured above. They all appear to be out of stock except for maybe xxcycle and the info goes back to 2019.

I wonder how strong the cast aluminum extensions attached to the steel quills are on those Humbert Dino-X stems. Probably OK for around town use but I wouldn't feel comfortable with an average sized or larger adult using one of those off road.

Also, I wouldn't recommend removing 1.1mm+ off of the diameter of a 22.2mm aluminum stem like those tall boys from Nitto. The wall thickness of the quill would probably end up being too thin.


Here's a suggestion: get an old steel 21.1mm MTB stem with a brake cable roller that you like and have an extension TIG welded to the bottom of the quill???




Back in 1991 I built this lugged Reynolds 531, 700c off road trekking frame. I had some neck problems and Salsa made me this short reach, high rise stem. Solved a bunch of problems!



One last thing, I just saw these Cro Mo steel stem extensions. Dirt cheap!

https://www.ebay.com/itm/153723416080

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Old 09-24-21, 02:55 AM
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First of all congrats on considering the drop bar conversion, a huge upgrade for any rigid frame MTB in my opinion. I had the same problem with a early Mongoose MTB that used 21.1 because Mongoose did mostly BMX stuff at the time. Luckily I have sort of long arms and didn't need the bars all that high so I could get away with a AL quill road stem from a Schwinn. Are you 100% sure a standard quill road stem won't work? Something I almost did until I found my stem was to just switch the fork out for a 22.2 fork and and headset to see if that worked. You might have to re-use the cups and piece together some threaded 22.2 headset parts that fit the cups but as long as the fork fits through I don't see why it wouldn't work. I'd do that before I'd alter the original fork. Or get a donor 21.1 fork and ream that out. I'm sure you know threadless adapters are out there, its just too bad threadless stems are the ugliest bike part in existence.
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Old 09-24-21, 03:48 AM
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Originally Posted by verktyg
Being unfamiliar with MTB and BMX stems and forks from that era, what's the outside diameter of the steerers that take a 21.1mm / .830" stem?

Easiest way to tell is what's the thread size of the headsets?

I don't know the OD, yet. i'll have take things apart and apply the ol' calipers. hopefully later today (i'm up way too late...lol)

If it's 1", the steerer can be bored out to 22.2mm on a mill or a lathe. Trying to ream out 1.1mm is a LOT of work. Reamers are intended to remove a much smaller amount of material to accurately resize a bore.

The fork would need to be rigidly fixtured on either a mill or lathe while boring it out, otherwise the cutting tool can easily grab inside the bore and you have a mess! (Been there - done that).

Several other things: the bore should have a taper at the bottom of the resized area rather than a sharp shoulder to reduce the possibility of a stress riser and... make sure that the expander wedge is below the threaded area of the steerer. 75mm to 80mm is the recommended minimum amount of insertion for the stem into the steerer.

hmmm...i'm thinking blow off mod'ing the fork, then. that sounds....tricky! i'd literally jump off a bridge if i messed up this fork. it's one of a kind. and, i suppose i don't need to go messin' up my pretty face on the pavement

There are a number of European websites that list the Humbert Dino-X 21.1mm / .830" Stems pictured above. They all appear to be out of stock except for maybe xxcycle and the info goes back to 2019.

I wonder how strong the cast aluminum extensions attached to the steel quills are on those Humbert Dino-X stems. Probably OK for around town use but I wouldn't feel comfortable with an average sized or larger adult using one of those off road.

it's a good question. it's how my ross stem is constructed, and humpert is a brand i'm familiar with. over the years i've seen the name thrown around particularly in the euro touring groups. so, perhaps it's quality despite unfamiliarity.

Also, I wouldn't recommend removing 1.1mm+ off of the diameter of a 22.2mm aluminum stem like those tall boys from Nitto. The wall thickness of the quill would probably end up being too thin.

yeah, i know...that's a crazy idea. but, i've seen some pretty thick alloy quill inserts. they're heavy! i've a promax like that, but it's also 1 1/8. probably best to blow off this mod'ing idea, too


Here's a suggestion: get an old steel 21.1mm MTB stem with a brake cable roller that you like and have an extension TIG welded to the bottom of the quill???



now, that gives me an idea!!! but, before i expound upon it here, i'll have to take some measurements of potential frankenparts beforehand. i'll report back on this


Back in 1991 I built this lugged Reynolds 531, 700c off road trekking frame. I had some neck problems and Salsa made me this short reach, high rise stem. Solved a bunch of problems!



i've seen that bike before!!!! i ran a google search on "short quill stems" and a BF thread popped up with that and several other bikes of yours shown.

One last thing, I just saw these Cro Mo steel stem extensions. Dirt cheap!

https://www.bikeforums.net/classic-v...per-sport.html

i didn't see much helpful info in that thread, but i know of the cromo extensions you speak of. my above reply of "frankenparts" will include one IF measurements pan out fortuitously

verktyg
thank you kindly for the detailed reply. i've made replies in red....as you may notice
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Old 09-24-21, 04:01 AM
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Originally Posted by degan
First of all congrats on considering the drop bar conversion, a huge upgrade for any rigid frame MTB in my opinion. I had the same problem with a early Mongoose MTB that used 21.1 because Mongoose did mostly BMX stuff at the time. Luckily I have sort of long arms and didn't need the bars all that high so I could get away with a AL quill road stem from a Schwinn. Are you 100% sure a standard quill road stem won't work? Something I almost did until I found my stem was to just switch the fork out for a 22.2 fork and and headset to see if that worked. You might have to re-use the cups and piece together some threaded 22.2 headset parts that fit the cups but as long as the fork fits through I don't see why it wouldn't work. I'd do that before I'd alter the original fork. Or get a donor 21.1 fork and ream that out. I'm sure you know threadless adapters are out there, its just too bad threadless stems are the ugliest bike part in existence.
well, thanks! it is certainly something i've wanted to do for a long time, but never had quite the bike for it. (although i have a scott tampico that might qualify for a dirt drop hard tail. time will tell when i get to it)

i'm quite sure a regular 22.2 quill won't fit. i tried the very first thing. i have a chrome velo orange 17 degree riser stem that has just the right height and reach (and, appearance), but alas....no go

i will never swap out the fork on this ross. it uses roller cam brakes front and rear. and, it's chrome..as is the whole frame, so it totally goes with the package

i did consider adapting a threadless stem to it. the only one that would even be close to looking right for the vibe of the bike would be something like the velo orange cigne stem. but, that sucker's expensive. and, it has a 31.8 clamp. not doin' it...haha. it would look to "chunky", i think.

anyway, all points taken and i'll have a look at things with them in mind....
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Old 09-24-21, 04:45 AM
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Sheldon Brown's site suggests the OD of the steer tube is still 25.4mm...it's just a tube with a higher wall thickness with a smaller ID than what was used for ISO 22.2mm stems.

Sheldon Brown's Bicycle Headset Dimension Crib Sheet
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Old 09-24-21, 07:22 AM
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Originally Posted by thook
well, thanks! it is certainly something i've wanted to do for a long time, but never had quite the bike for it. (although i have a scott tampico that might qualify for a dirt drop hard tail. time will tell when i get to it)

i'm quite sure a regular 22.2 quill won't fit. i tried the very first thing. i have a chrome velo orange 17 degree riser stem that has just the right height and reach (and, appearance), but alas....no go

i will never swap out the fork on this ross. it uses roller cam brakes front and rear. and, it's chrome..as is the whole frame, so it totally goes with the package

i did consider adapting a threadless stem to it. the only one that would even be close to looking right for the vibe of the bike would be something like the velo orange cigne stem. but, that sucker's expensive. and, it has a 31.8 clamp. not doin' it...haha. it would look to "chunky", i think.

anyway, all points taken and i'll have a look at things with them in mind....

I've done two things on old Ross's. Either buy a 21.1 angled quill stem new (get one with a two bolt removable face plate for added convenience). I also have picked up a few at co-ops. The other choice is to covert to threadless. I did this on another Ross Mt Hood chrome drop bar conversion. Agree, no way I would lose that chrome fork! I think I posted a picture of it on the drop bar conversion thread.

The last one I bought was a Sunlite brand from Niagara Cycle. Not sure where I would go now.

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Old 09-24-21, 08:59 AM
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Originally Posted by thook
well, thanks! it is certainly something i've wanted to do for a long time, but never had quite the bike for it. (although i have a scott tampico that might qualify for a dirt drop hard tail. time will tell when i get to it)

i'm quite sure a regular 22.2 quill won't fit. i tried the very first thing. i have a chrome velo orange 17 degree riser stem that has just the right height and reach (and, appearance), but alas....no go

i will never swap out the fork on this ross. it uses roller cam brakes front and rear. and, it's chrome..as is the whole frame, so it totally goes with the package

i did consider adapting a threadless stem to it. the only one that would even be close to looking right for the vibe of the bike would be something like the velo orange cigne stem. but, that sucker's expensive. and, it has a 31.8 clamp. not doin' it...haha. it would look to "chunky", i think.

anyway, all points taken and i'll have a look at things with them in mind....
When I meant regular stem I meant a 21.1 stem but with regular road stem angles and rise as opposed to a 21.1 MTB stem. Also a 22.2 chrome fork with roller-cams shouldn't be hard to find. Keep the old one for if/when you want to go back to original, find a "close enough" fork to mess around with to have more compatibility. A lot easier to then trying to whittle down a stem or ream out a steerer tube.
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Old 09-24-21, 11:42 AM
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I found a 21.1 threadless adapter for my Univega and am in the process of building it up using VO’s 17-degree stem. I’m not so concerned about looks as much as function, and it seems to solve my issue. I’m using upright Albatross bars, so ymmv for a drop conversion.

I found it on ebay a few months ago, will edit this post if I find the link.

EDIT: Here’s the link - https://www.ebay.com/itm/New-SILVER-...8-fbe0f966831c



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Old 09-24-21, 07:23 PM
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Originally Posted by wrk101
I've done two things on old Ross's. Either buy a 21.1 angled quill stem new (get one with a two bolt removable face plate for added convenience). I also have picked up a few at co-ops. The other choice is to covert to threadless. I did this on another Ross Mt Hood chrome drop bar conversion. Agree, no way I would lose that chrome fork! I think I posted a picture of it on the drop bar conversion thread.

The last one I bought was a Sunlite brand from Niagara Cycle. Not sure where I would go now.
yeah, i don't want to do threadless unless i had the money for a cigne stem. or, by sheer luck, an old school LD stem on ebay
i'll have to look for your pic on the thread, then. thanks!
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Old 09-24-21, 07:30 PM
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Originally Posted by degan
When I meant regular stem I meant a 21.1 stem but with regular road stem angles and rise as opposed to a 21.1 MTB stem. Also a 22.2 chrome fork with roller-cams shouldn't be hard to find. Keep the old one for if/when you want to go back to original, find a "close enough" fork to mess around with to have more compatibility. A lot easier to then trying to whittle down a stem or ream out a steerer tube.
no, i have not. it would simply be much too short to get the handlebars high enough. i have roughly 16-17 cm's of seat post exposed, so the saddle's pretty high relative to the head tube. fyi, the top tube is horizontal

yeah, i don't know about that finding a chrome fork with roller cam posts. i've done a lot of ebay lurking and i've never seen one. otoh, i haven't been looking for one, either.
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Old 09-24-21, 07:32 PM
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Originally Posted by noobinsf
I found a 21.1 threadless adapter for my Univega and am in the process of building it up using VO’s 17-degree stem. I’m not so concerned about looks as much as function, and it seems to solve my issue. I’m using upright Albatross bars, so ymmv for a drop conversion.

I found it on ebay a few months ago, will edit this post if I find the link.

EDIT: Here’s the link - https://www.ebay.com/itm/New-SILVER-...8-fbe0f966831c

i've seen those. those wouldn't be tall enough. however, sunlite makes cromo ones that would. it's on my short list of possibilities, too. thanks!!

very nice 'vega, btw!!! <<dang>>
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Old 09-24-21, 07:37 PM
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Originally Posted by hokiefyd
Sheldon Brown's site suggests the OD of the steer tube is still 25.4mm...it's just a tube with a higher wall thickness with a smaller ID than what was used for ISO 22.2mm stems.

Sheldon Brown's Bicycle Headset Dimension Crib Sheet
well, now...see....that's what i've been wondering this whole time. i just haven't taken things apart to check. and, that's why i'd wondered about honing/milling out the steer tube to fit 22.2. so, if that's doable, there's a framebuilder in town that i know that can do it!! IF it don't cost too much. i'll have to call him. thanks!!!!

ps. yes...i know...i could've called him from the beginning, but really i hate to "bother" him unless i have definite plans and fortified with research to do business. he's got a young family and very busy
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Old 09-24-21, 07:51 PM
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ah, i just remembered. i bought this stoker stem a couple of years from ebay thinking it was a regular one inch threadless stem. that is what it was advertised as, and i didn't know any better. it's an '89 sakae tandem stoker stem. this with a quill adapter/extender??....



what do you guys? opinions? would it look....too odd? of course, it's on me and won't know 'til i try.
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Old 09-24-21, 09:26 PM
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Originally Posted by thook
no, i have not. it would simply be much too short to get the handlebars high enough. i have roughly 16-17 cm's of seat post exposed, so the saddle's pretty high relative to the head tube. fyi, the top tube is horizontal

yeah, i don't know about that finding a chrome fork with roller cam posts. i've done a lot of ebay lurking and i've never seen one. otoh, i haven't been looking for one, either.
Find a co-op. The one near me had tons and tons of roller cam forks because people would come in and trade them out for a standard canti fork and donate the left over roller cam fork.
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Old 09-24-21, 09:27 PM
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What's the ID of that stem's lower clamp?

That was designed to clamp onto a specific size of seatpost, probably a mm or two smaller ID than the OD of the steel extender(?).

Possibly it could be shimmed to fit some kind of 21.1mm extender, or maybe the stem can be subtly enlarged to fit the extender's ~28mm OD.

I managed to increase the ID of this 25.4mm stem clamp in a way that accurately self-centered the bore size with the existing bore, using stuff at home like the bench vise, beltsanding belt, and wooden dowel.
I used an Allen key in the clamp slot to adjust the diameter as I slowly removed a uniform amount of metal from the ID of the clamp.
Lol, later I discovered that I could order the very same stem but with Kalloy branding in the 26mm ID size. These are the stems that are sized to fit both 22.2mm and 22.0mm stems, so went on my Steyr-built SEARS 10 SPEED together with the 26mm handlebar that had the bend and reach that I wanted.



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Old 09-24-21, 11:28 PM
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Originally Posted by degan
Find a co-op. The one near me had tons and tons of roller cam forks because people would come in and trade them out for a standard canti fork and donate the left over roller cam fork.
the only co-op type place we had closed years ago. i'm narrowing things down to come up with my solution, though. like i said, i'm also going to see about getting this fork reamed. but, it's probably gonna be more than i have

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Old 09-24-21, 11:42 PM
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Originally Posted by dddd
What's the ID of that stem's lower clamp?

That was designed to clamp onto a specific size of seatpost, probably a mm or two smaller ID than the OD of the steel extender(?).

Possibly it could be shimmed to fit some kind of 21.1mm extender, or maybe the stem can be subtly enlarged to fit the extender's ~28mm OD.

I managed to increase the ID of this 25.4mm stem clamp in a way that accurately self-centered the bore size with the existing bore, using stuff at home like the bench vise, beltsanding belt, and wooden dowel.
I used an Allen key in the clamp slot to adjust the diameter as I slowly removed a uniform amount of metal from the ID of the clamp.
Lol, later I discovered that I could order the very same stem but with Kalloy branding in the 26mm ID size. These are the stems that are sized to fit both 22.2mm and 22.0mm stems, so went on my Steyr-built SEARS 10 SPEED together with the 26mm handlebar that had the bend and reach that I wanted.

i've read of your solution/sanding before in a couple of other threads on stems. this stoker stem has a seat post clamp size of 26.4 or .8. not sure at the moment. however, i made a shim for it already so it would fit on 1" threaded/threadless quill adapters. it works really well. nice and solid...ie. no slipping. but, the bar clamp itself is 26mm
anyway, the problem i may run into with this stoker, after mocking things up just a little while ago, is the reach. it's 10cm's. i could get some soma portola bars and the reach (65mm) would work fine vs the rando bars i mocked up (95mm reach). but, i'll have to weigh the cost for the portola vs reaming the fork to decide. i'd kinda rather use the rando bar, anyway. i have an 80mm reach dirt drop stem if the reaming works out. won't know until i get to assembling things. i have a ratty looking quill adapter i'm going to sand down the insert diameter on for a test fit
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Old 09-25-21, 01:50 AM
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You would be an idiot to try to ream the headtube to try and make the headtube accept the "long time industry standard 22.2mm" stem RATHER than the "1966 & LATER SCHWINN STANDARD 21.1mm SIZE".

The whole reason that SCHWINN introduced the thicker walled, strongest headtube in the industry in 1966 is because that added strength according to Schwinn engineering made for a better handling, and safer bicycle.

Now you want to take your ROSS, which obviously saw reason to construct this model to the stronger, thicker walled headtube like Schwinn,.......YOU WANT TO REAM IT SO YOU CAN FIT A MORE ATTRACTIVE LONGER REPLACEMENT STEM............serious dumbass move!!!

Sure, there were not many manufacturers other than 1966-on Schwinn and some of the Panasonic Japanese Imports that Schwinn labeled and badged in their lineup
You'll have to search a while for a possible aluminum stem from 40 some odd years ago that meets the extended length that you need. There were probably a few quality aftermarket 21.1 aluminum quil stems in the extended length that you desire. Given that quill stems have been gone for decades except on inexpensive beach cruisers that you might find at Walmart, you're not gonna find new anything at local bike shops unless you can jump in Ziggy's time machine and take the Quantum Leap back to 1982. Keep looking, you'll may find something after a while.... Don't try to ream the headtube as that is just beyond stupid! You would be better off having a machine shop reduce a 22.2 diameter stem to 21.1mm diameter using your existing 21.1mm stem as a guide. I don't recommend that because the cost to do so might not be suitable to you, but a professional machinist could possibly get a reduction of such a part that would retain its strength and integrity. Maybe some cat you went to school with has a machine shop, or that cat's son has a machine shop, or your son-in-law that builds race cars might have a buddy at a machine shop. It is fairly easy work as long as the reduction leaves enough meat on the 22.2 stem after reducing it to 21.1mm. The machinist should be able to immediately eyeball the 22.2mm part along with your existing 21.1mm part and tell you definitively, if it can be done or not with that particular 22.2mm stem--------reducing to 21.1mm. IT MAY JUST BE TOO RISKY WITH AN ALUMINUM PART of UNKNOWN ORIGIN & INTEGRITY.........I haven't yet investigated it enough to accurately say.
You absolutely don't wanna take chances with your steering controls.

Have you looked at possibly using a stock stem from a Seventies era Schwinn Continental, as that would be aluminum and 21.1mm? The only question would be would it be useful in the length department or would it still be too short.
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Old 09-25-21, 02:33 AM
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Here is an oldie but goodie, SEE Post #15 from the legendary SCOOPER on 08-28-09 in the link below. SEE Post #20 from SCOOPER also.

https://www.bikeforums.net/classic-v...21-1-stem.html

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Old 09-25-21, 03:39 AM
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Standardized Nomenclature

Vintage Schwinn

Good points about trying to ream out the bore in the STEERER.

Reamers are designed to remove a small amount of material to accurately size a hole that is close to the finished diameter.

The maximum recommended amount of material for reaming steel is 2% to 3% of the reamer diameter.

21.1mm = .830" x 2% = .014" = .007" per side - the depth of cut
21.1mm = .830" x 3% = .025" = .012" per side - the depth of cut

Removing 1.1mm of material (.043" or .022" per side) from the bore can be done taking multiple passes with an adjustable reamer but it can be a lot of work.


On another topic and suggestion:

Using standardized terms for bicycle parts and components makes it easier for folks to understand descriptions, especially for the many BF members who are located outside the US and English isn't their native tongue.

The HEAD TUBE is the tube at the front of the main triangle where the headset mounts.



The tube attached to the fork crown that the stem fits into or onto is called the STEERER.



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Old 09-25-21, 12:44 PM
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Originally Posted by Vintage Schwinn

Have you looked at possibly using a stock stem from a Seventies era Schwinn Continental, as that would be aluminum and 21.1mm? The only question would be would it be useful in the length department or would it still be too short.
too short, but thanks
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Old 09-25-21, 12:56 PM
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Originally Posted by thook
something like this would be super if it were taller.....

https://www.ebay.com/itm/284221217099

i heard back from the seller on this item. she took measurements and it's taller than i'd assumed by the eye. won't know until later when i can measure things out on the bike. at work today. i've got my fingers crossed because this would be super. it's the right shape and reach for what i'm going for
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