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Old 05-18-06, 09:15 AM   #1
TallRider
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21.15mm quill stem with manufacturing defect - what to do? (pics)

I've not yet ridden it much, but I've noticed that the stem on the Schwinn Traveler that I converted to a fixed-gear, rocks side-to-side when torque on the bars while sprinting or climbing out of the saddle. The quill stem is one of those old, smaller-diameter ones - 21.15mm or 0.833" quill width (Typical quill stems for 1" steere tubes are 22.2mm; the old Schwinns and some other bikes have the 1" outer diameter of the steerer tube, but the tubing walls are thicker so the interior diameter is 21.15mm instead of 22.2mm.) I've tried raising and lowering the quill stem, tightening the bolt really tight, etc., and no change - the stem still rocks back and forth slightly but noticeably.
I've got another Schwinn with the same dimension steerer tube and quill stem, so I swapped the stems back and forth to isolate the problem: stem or bike?

Turns out the machined angle at the bottom of the quill stem, the part that contacts against the wedge which tightens to hold the stem in the steerer tube, is machined at a slightly wrong angle, so that the bottom of the wedge contacts the quill, but the top of the wedge is set a bit away from the quill. The stem that doesn't rock, from the other bike, has the angle machined such that the wedge is flush against the bottom of the quill over its whole contact area. And I made sure that both wedges are exactly the same dimension, and I even switched them back and forth between the stems. The problem is entirely with the aluminum part of the quill stem from the Traveler. Here are some pictures.

Good stem:


Bad stem:


Also, here are two shots of the stems when the quill is loosened a bit. Angle and contact stay the same in both instances.

Good stem:


Bad stem:


It appears that the original machining on the bad stem was done at a slightly wrong angle.
I don't know what to do here. I can't swap the good stem out for the bad one, because the bad one is 10cm extension and the good one is 8cm, and I want the longer extension.
Here are my options:
1. machine the quill to the optimal angle. This is doable, though tricky, but I don't have the tools. I assume a belt sander would work best? Could a bike shop do this for me?
2. buy a new stem. Only, stems in 21.15mm quill are very hard to find, especially with a long (10 or 11cm extension). The old SR stems come up on eBay every now and then, but usually the seller doesn't realize that they are for a smaller dimemsion, and I need to figure that out from pictures. Even so, the ones that come up are usually 8cm, not 10 or 11cm. There is a local bike co-op of sorts, and they may have something. Bike shop may have something in a bin, too.
3. sand down a 22.2mm quill stem. This is a lot, though, removing 0.5mm of quill width all the way around. Would take a long time Probably safe, as the old SR stems at 21.15mm appear to be identical to the SR stems for 22.2mm, but the 21.15 were simply machined down narrower - there's a nice little ridge where the narrower part starts.
4. ream the steerer tube out to 22.2mm internal diameter so it accepts regular quill stems. Since the outer diameter of the steerer tube is normal 1", I assume that this would be okay and not unsafe - the dimensions would end up as that of a typical fork. However, it may be difficult to do, and/or expensive.

Any feedback is appreciated. Thanks.

Last edited by TallRider; 05-18-06 at 01:46 PM.
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Old 05-18-06, 09:32 AM   #2
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I don't know Tim. It's kind of annoying to have to get hard to find items like a 21.15mm stem. If that was me i'd pickup a new fork (assuming you don't have a very expensive one already). or ream the steerer.

I'd do 3 if not wanting to spend much money but it sounds like it would take a while. Advantage of ream/new fork is that regular size quill stems are like $10 in a million lengths...

Flip a coin?
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Old 05-18-06, 09:39 AM   #3
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Thanks for the thoughts. Do you know how much it would cost to have a bike shop ream the steerer? I guess I'll just head down there, bring the quill stems, and ask them if it would cost more to ream the steerer or sand down the quill's contact area with the wedge so that it's at the correct angle.

A new fork probably isn't an option, for a few reasons.
* I like the paint job
* it's for a 27" wheel
* the head tube is really, really, really long
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Old 05-18-06, 10:27 AM   #4
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A flat smooth cut file properly applied should fix the problem. File a bit on the high spots, check for fit, repeat. Lowes, Home Depot, Sears or the local Ace Hardware should have a suitable file fairly cheap.

I wouldn't go to the expense of machining the quill or reaming the steerer either. The Al quill should be rather easy to hand file to the proper angle. Just go slow and try-fit frequently.
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Old 05-18-06, 10:57 AM   #5
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Good thought, HillRider. I've actually got a file, and already used it to remove a bur from the contact surface of hte wedge, that I'd thought might be causing the problem (it wasn't). should work like butter on the aluminum. I may try a belt-sander if the file is too much of a pain; I've got a neigbor who does lots of carpentry.

As for other options, the bike shop mechanics looked at me blankly when I asked about reaming the steerer tube - they had no idea how they'd do it, apparently, and didn't have the tools. Framebuilder stuff, apparently.
I was surprised that they had no constructive thoughts on the issue. But then again, they don't spend time working old bikes over. And on my end, I've never actually touched a threadless steering system, or integrated crank/bb system, unless you count steel ashtabula one-piece cranks in the latter category
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Old 05-18-06, 11:29 AM   #6
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Are you sure the problem is in the stem and not the wedge? Maybe you can just swap wedges. Worth a try at least.
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Old 05-18-06, 12:49 PM   #7
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Quote:
Originally Posted by HillRider
A flat smooth cut file properly applied should fix the problem. File a bit on the high spots, check for fit, repeat. Lowes, Home Depot, Sears or the local Ace Hardware should have a suitable file fairly cheap.

I wouldn't go to the expense of machining the quill or reaming the steerer either. The Al quill should be rather easy to hand file to the proper angle. Just go slow and try-fit frequently.
+1 This sounds like the best approach to me. Best case, you get it to work, worst case, you're no worse off than you were before. If it absolutely won't work, start scouring ebay for one of those "ridged" stems in the size you want. There are some big sellers that seem to always have a good variety of SR stems, seatposts, Dia-Compe and Weinman brakes, etc. Good luck with it-
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Old 05-18-06, 01:13 PM   #8
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It looks to me like the wedge just got drilled off angle. I'd just file it down. Better yet, head out to the LBS and look for a used wedge. It's not like it's a precision machined part.

One thing that I noticed from all of your pictures is no grease on your stems. Maybe you just cleaned it off for the pictures, but those stems need lots of grease. Make sure to get plenty in the angled space between the stem and the wedge and cover the wedge as completely as you can. Wedges are just cheapo steel castings that are drilled and tapped. If you don't grease them they will rust and often get severely stuck. Unthread the wedge and make sure you get a good dollop of grease on the bolt threads. Also, make certain to get the contacting surfaces of the stem and the wedge well greased so they can slide against each other.

In your original post you say that the stem is rocking from side to side. I would not believe that is the stem. That's the headset. If the stem is rocking, then there has to be some gap between the outside surface of the stem and the inside surface of the headset bearing race. These should fit very closely. Get some calipers and measure. They should be within 0.5mm or less. If they don't then there is a mismatch and your handlebars will rock. How the quill&wedge are seated have nothing to do with that. Did you buy this bike new? If not, it's possible that the stem got replaced at some point and they installed one with the wrong O.D. and did not properly match it to the headset. You could install a shim in there to stop the movement. It's better to get a stem and headset that match properly.
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Old 05-18-06, 02:10 PM   #9
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I'd say if there's a mismatch between stem and headset, it would be the headset (or part of it) that's been switched out, not the stem. The Schwinns of that era definitely used that size stem (.833"). But if the top nut on the headset is for a standard (22.2mm) quill, that might be the problem. Along those same lines, I recently tried to install the top nut off of a headset that had been on a Schwinn (21.15mm stem) and put it on a standard fork/stem (22.2mm), and the inside diameter of the nut was too small for the 22.2mm stem. I used my dremel tool to sand it out a little, and it fit fine. So you might take a look at the space between the inside of the top nut and the stem. There shouldn't be a noticeable gap there. If there's a space between these two parts, the stem might not be supported properly, and that might be what's causing the movement.
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Old 05-18-06, 02:49 PM   #10
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Well, this is baffling. I thought that I'd swapped the wedge bolts last night, to isolate whether the problem was the aluminum quill stem or the wedge bolt. But I guess I hadn't. But after gorn and cascade168 mentioned the wedge, I tried swapping wedges again, and noticed that now neither stem has side-to-side play in either bike's steerer tube. It's all the more strange because the stems appear to be machined at the same dimension, and the difference is in the wedge bolt of the initially-problematic stem having been drilled off-kilter.
But then I swapped the wedge bolts back, having the off-kilter one on the initially rocking stem, and it doesn't rock anymore. Earlier, there was a clear feeling of rocking when I torqued on the bars, with crisp outer limits, not just flexing of the stem.
Anyway, this fits with The Fixer's experience, that slightly off-kilter wedge/quill interfaces don't matter too much. But now I have no idea what was causing/allowing the rocking earlier. The only thing that I've done is a little bit of filing of burrs on the wedge and bottom of the quill of the stem that was rocking earlier. So, that may have cleared things up.

On other points:
HillRider mentioned eBay for these old Ridged stems. I've been looking lately, for the last three weeks, and have yet to see one longer than 80mm. But will keep looking (though not as hard now, as things appear to be working okay).

cascade168 said that there should be no ability to rock. Which is true, unless you're talking about a small bit of rocking. Any quill stem fits into the steerer tube with a small bit of play, so that the interface isn't a pain to work with; usually tightening it into the tube eliminates that play. Both stems are the same size, both labeled 0.833 (inches) on the back, both from SR, and before tightening the wedge, the two stems have the same or similar amount of slight play within the steerer tube.

Both stems are original - both bikes had the original handlebar tape on them, never been unwrapped. Per well biked's question, the top nut fits perfectly in both stems.

And, the headset is perfectly adjusted. It was definitely the stem. The problematic stem rocked on both bikes, while the other stem didn't rock on either bike.

And yeah, I'd just wiped the grease off when removing the stems to experiment with different combinations.


So, in conclusion, I don't know what the problem was. Which is annoying. But it's at least happy, that there's no problem I can find now. Thanks for the suggestions, and sorry to have (apparently) led y'all on a goose chase.
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Old 05-18-06, 03:09 PM   #11
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One more thing, and this really helps to solve whatever problem may have existed.
I'd first realized that the quill was smaller and the steerer tube narrower when I tried to stick a 10-year-old welded aluminum quill stem into the Schwinn Traveler, instead of the old forged SR stem. The newer stem didn't fit into the head tube. In fact, the wedge (which was made of aluminum on that newer stem) didn't even fit through the headset's locknut.

However, I've got a Nitto quill stem, for standard 22.2mm steerer tube, that had a steel wedge on the bottom. On a whim, I tried to put the steel wedge into the steerer tube of the Schwinn, and lo and behold, it fit! And this despite the wedge having 0.875 stamped on the bottom (0.875" = 22.2mm). So, I replaced the off-kilter-drilled wedge with the wedge from the Nitto stem, and will grab another newer designed-for-22.2mm aluminum wedge to use with the Nitto stem whenever I start running it again.
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Old 05-18-06, 05:00 PM   #12
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It's always nice when a problem is found to be not a problem. For the record, I wasn't the one who suggested E-bay. I'm always leery of them.
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Old 05-19-06, 12:37 AM   #13
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Tim,

I think I've got one on an old junked traveler. I'll see if its the narrow stem tomorrow.
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