etherhuffer 

I had a friend put a Technomic in his lathe and bring it down to 21.1. For safety reasons I cannot tell others to do this. That said, I think putting a caliper on an old 21.1 stem and then the Technomic will tell you how much wall you have to work with. If no thinner than the OEM 21.1 stem you should be safe.If you look at old Schwinn stems, the top is larger, then it steps down to 21.1 Of note, I polished that thing like crazy after we cut it down. I worry that a cut surface can lead to crack formation. The bike its on does not get used at extremes, I don't stomp and reef on the bars. That said, its my noggin I have to deal with, not yours.
It would really be nice if Nitto would do a 21.1 stem. I asked Grant at Rivendell and he said there is just not enough demand. Same at Velo Orange. Good luck on the project, its really a pain in the rear.

degan

If you're willing to destroy the steerer tube by reaming it you might as well just cut the steerer tube off have a 22.2 steerer tube welded on.

thook

i'm not "willing" to destroy the steer tube. originally just asked if it was possible or even feasible. then, i considered it might be possible based on a couple of replies in the thread despite what some have said. and, i guess there's a difference between boring and reaming. I don't know. it's all moot, anyway. i'm not going to do it. i'm just gonna get the promax 21.1 stem i posted a pic of earlier from ebay. simple, cheaper, and certainly safer

thook

thanks! yes, it is kind of a pain...a challenge. but, i have a solution, now, and i think it's gonna look and fit great. it should put the top of the handlebar just a bit above the saddle height.

macstuff 

A lot of trouble and thought going into getting a fork with a 22mm steer tube.
Boring out the steer tube is not a viable option. In the end you will have to tighten it down and the swedge or expander will tear the steer tube. Once you've bulged your steer tube and the bike rides wonky and it won't come out of the head. Then there will be another problem to think about.
Milling down the stem is an answer looking fora problem.
21mm was for Schwinn after 1966' and all the companies that would buy that size discounted because it wasn't popular (Ross apparently was one). Yet Schwinn didn't make and patent their own 21mm stems so it wasn't a completely proprietary deal. Anyone could and some did.
Get a new fork.

jdawginsc 

That's what I was going to suggest, actually. Find an extension that suits your height and add a stoker stem

Here are some various ebay links I saw...
https://www.ebay.com/itm/17418181693...4AAOSw8gdeL4S-
https://www.ebay.com/itm/38230213967...YAAOSw-0xYQb~R
https://www.ebay.com/itm/14300670653...UAAOSwWB5b5Npk

https://www.ebay.com/itm/22451114772...sAAOSwpT9g1r1L

thook

now, do you actually know what you are talking about or is this conjecture? are you a frame builder? have you done anything like this before? get a new fork? have you not read a thing i've said in this thread? or what anyone else has said?

macstuff 

Thats ridiculous, you don't have to be a frame builder.
I have the deepest of mechanical experience a person can have, and what you are talking about doing is fundamentally wrong and dangerous. It has nothing to do with bikes and everything to do with a mild steel tubing, even ChroMo for that matter.
That doesn't mean don't do it, go ahead.... by all means, learn.
How does a stem attach?
One of the reasons that Schwinn went to 21mm stems was to bring the warrantee claims down. They were lifetime warrantee bikes.
When they did that, their "approved" suppliers had 21mm machinery to make stems for other companies. Cheaper so a few companies bought. Not many.
What was happening, and what will happen to yours, is a common occurrence. Tightening and loosening the stem again and again, or even a couple times too hard will push the wedge out and tear and bulge the steer tube. It may even be too thin to act as a footing for the swedge and push through the first time you tighten it down. The question isn't can you, it's should you.
As you mentioned somewhere up there, it must be hogged out to more than 22mm.... whatever to fit. there has to be wiggle room to insert the stem.
The steer tube becomes too thin. There are threads there on the outside not helping with this situation also. At that point it is a danger to ride.
I've pulled apart many old bikes with bulged steer tubes. It was a common occurrence in the "old days"
Best is to just buy another used fork for $30-50. We have a co-op salvage here where a proper 22mm i.d. fork for that would be $6

Im not dissin ya', you're just over thinking it as far as the steer tube is concerned.
Turning down, grinding down, honing down the stem is still just a hard answer to an easy question.
A cheap fork and you have a worldly choice of stems. Even a stoker adapter stem would be a good choice.
Just sayin'

dddd

Manufacturers budget their design, testing and tooling over many thousands of units, so can produce a safe, consistent product at low cost.

Whenever we modify something, we forego the testing stage altogether before actually using it on our bike. So we must be mindful of ALL the possible repercussions.

We don't for example know much about how the steerer seam was welded and thus how it (the seam weld) would hold up to any reaming or boring operation.

My gut tells me that carefully done, this could be fine. Most steerer bulge-outs I've seen were due to someone using a big wrench and severely over-tightening the quill bolt, because they didn't know any better.

I note that GB made stems of identical design but with different quill OD's, 21.1 and 22.2, and I measured the ID to be the same on both stems. So they trusted that metal!
We don't know however why they trusted it. But Schwinn actually tested stuff like the stems they bought, they had very high standards.

I modified my stem's bar clamp after considering the beefy appearance of the clamp, and noting that it was made by the world's largest supplier of such stems AND that I weigh only 142lbs. I made the judgement without any testing and am living with it. I know that the size of the rider has a very direct correlation to many bike part's realized durability and safety, and this affects my judgement a great deal.

dddd

One more consideration here is the very long length of the OP's needed stem quill, suggesting that steel might be the preferred material in this case. Also the type of handlebar and levers will affect the leverage loading in the same direction that the quill's extra length is causing higher bending force, which may combine to produce extremely high stress at the lower end of the quill. The GB stems I mentioned did not have an extended length quill nor any rise to their (horizontal) extension.

thook

i'm only going by what was told me here at least once...THAT IT CAN BE DONE. and some of ya'll seem to think i'm dead set on doing it. i'm not overthinking. if i don't fully understand something, i will ask questions until i do....unless i get frustrated and say eff it. but, given the contradictions between replies in this thread, isn't it easy to see where one might be inclined to continue questioning? for example, if the OD on a 21.1 and 22.2 steerer are the same, then milling the inside of the 21.1 would bring the wall thickness to the same as a 22.2 steerer, right? so, it would seem at least somewhat logical there's no problem given than millions of 22.2 steer tubes are out there UNDAMAGED. that being said, as it's been pointed out, there's risks. different types of steel. unknown factors. okay. i can accept that. i'd read elsewhere that one reason among others that schwinn used the 21.1 size was because they used a poorer quality steel and had to compensate somehow. and, eventually, they used better grades to where they then adopted 22.2. those bulged steerers i would imagine to be a symptom of that. plus, meat heads hammering down on the external hex head bolts that used to be used vs the allen heads. harder to torque those down as much....though, i'm sure it's been done

ps. of course you don't have to be a frame builder. that question was more about what are your qualifications? you gotta admit, there's a lot data that gets thrown around without experience to back it up. at least you didn't get ballistic like that one guy did...geez. iow's, thanks

thook

you see that curved promax i posted earlier? if correct, that's the same height i would get from any common dirt drop (ie. kalloy) quill at around 180mm to the insertion line. and, i will need all of that.

fyi, and fwiw, i'm not intending to take this bike/build down mtb trails or throwing myself off jumps with it. more of a gravel crushing light trail root hopper, if that makes sense.

thook

waaaiiitt just a minute. i have a question. okay....for the sake of discussion and learning ONLY, steerer tubes are not straight throughout. they taper getting thicker toward the crown. is this tapering or butting done with milling after the tubing has already been rolled and welded/drawn?

dddd

The taper-down area might get touched up with a milling process, but the tubes are butted to begin with.

The taper is kind of critical in that it has to be abrupt enough to prevent the stem from being wedged (even slightly) into the tapered area, since that would allow the stem to possibly lift free of the taper a millimeter and then suddenly be very loose.

In fact I once bought a Schwinn Circuit having such a short head tube and steerer that the OEM Cinelli 1A stem could not be inserted nearly to the limit line!
And what the PO did was to file away heavily at the end of the quill and wedge until it fit into the taper and got the limit line closer to the top nut.
Well, I was accelerating hard from a stop heading through an intersection and yep, the handlebar and stem lifted out of the steerer, not completely but with a complete/sudden loss of steering control. I threw out my left leg and kept myself upright with a couple of hard kicks to the passing pavement, and did make it to a stop without falling.

verktyg 

thook dddd

Many bikes were made with a straight piece of pipe for a steerer tube!

Back in the 70's maybe earlier, Peugeot, Motobecane and Raleigh to name a few European marques did it that way. They sometimes brazed in a split sleeve at bottom of the "pipe" to give some reinforcement in the fork crown area. It saved a few cents!

This photo shows the underside of a Peugeot U018 fork crown with a split sleeve.



Per dddd this shows the effect of a butted or tapered ID on a short steerer.




verktyg

macstuff 

I've had this same situation myself. One of the reasons I put together my own bikes is that Im mis-shapen from the standpoint of the commercial bike company. I have to have a smaller frame bike but a bit more arm room. This leaves me with small frames and long seat posts and long bar stems. At this point I've got all my riders dialed in but I had an early Schwinn Racer I bought with a crunched f/wheel, fork & handlebars. I went to the salvage and got the replacement parts and I really liked riding it around but had to raise the bars. Here is where I ran into your same problem. I had bought an entire 21mm front end and didn't realize the difference. I was stuck with 21mm choices and there really aren't any other than different post 66' Schwinn stems and very few aftermarket.
I admit.... I thought the same as you at first. Except with me it was fleeting. But I spent a lot of time trying to talk myself out of getting a proper fork. But when I finally did, I put an excellent fork on it and it rode sooooo much better. Also then put a long stem double adjustable on it and it is a real comfortable bike to ride.
That was a long time ago but I still have that bike and it wears the same fork and stem.

The first pic is the replacement cast iron Ashtabulah 21mm i.d. fork
The second is with an NOS Tange 7c fork that was Schwinn re-placement, still 21mm stem. It was 3/4 chrome wit ha cap
Third is with an unknown maker fork that I found at the salvage for $10. It is stamped Reynolds 531 and has Japanese tips. Socks and crown chrome. 22mm i.d.

thook

macstuff thanks for sharing yeah, i can see your dilemma and needing lots of post and stem. i've seen a couple of those types of stems in my searches on ebay and elsewhere. i'd have chosen either of them on a last resort basis. i've got a 21.1 stem on the way, though.