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Pin pointing an issue with quill stems

Old 12-08-09, 09:33 PM
  #1  
liberalswine
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Pin pointing an issue with quill stems

This is kind of simple, yet complicated at the same time, and not to mention perplexing. So I thought I'd get some advice on here.

In late August, I took a nasty spill due to my drops shifting while engaging in some sprints. Unfortunately, the last thing I remember was being off my seat and cranking hard. When I woke up, I had a crowd around me telling me not to move. This little mishap resulted in a broken shoulder- fractured scapulae to be exact.

When I received my bike back a month later, I was took more inspection to see why my drops shifted as described by a fellow rider who saw the whole thing during the incident. It appears that even when the nut on the quill stem was completely tightened, it shifted with a bit of force when hugging the front tire between my legs. So I thought, perhaps it was my quill stem. I was using a Nitto during the time and tried my other quill stem which was a specialized. I tried the specialized stem and it did the same thing. So I was certain that the steerer tube was pretty much done.

I bought a new Tange infinity fork for an awesome price of 30 bucks, got it cut and did the install. I then threw on the Nitto stem, tightened it up and the same thing happened. Then tried the specialized quill stem, same thing! So, now I thought it was the nut on both of the stems (sorry for lack of terminology) that were an issue. At this time, I remembered that I had an old Salsa quill stem that was in storage and tried that out. Surprisingly, it did! So at this point I was certain it was the nut. So, wanting to use the flashy nitto stem, I exchanged the nut from the Salsa stem and installed it on the Nitto stem. Unfortunately, the drops started to move again so my theory was completely washed down the drain.

Any suggestions to why the Salsa quill stem only works? It seems irrelevant that all of the quill stems are different lengths due to the fact that I've tried tightening the various combinations of these components at different heights.

Thanks!
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Old 12-08-09, 09:54 PM
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You're putting the stems in too far. See the section titled "Too low! Danger" at this link near the bottom of the page.

https://www.sheldonbrown.com/handsup....-compatibility
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Old 12-08-09, 09:54 PM
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Let's verifiy the clamp diameter of the bars, the stems and that the bar clamp area is not damaged or crushed in any way.
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Old 12-08-09, 10:01 PM
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Originally Posted by operator View Post
Let's verifiy the clamp diameter of the bars, the stems and that the bar clamp area is not damaged or crushed in any way.
Bar clamp area is not damaged from what I inspected. And as mentioned, the quill stems were installed at different heights just for trial and error. I'll get you guys the complete specs of the quill stems when I get a chance. Two of the stems are currently at my parent's place, so I won't be getting there til next week. I'll keep ya updated
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Old 12-08-09, 11:29 PM
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Originally Posted by liberalswine View Post
Any suggestions to why the Salsa quill stem only works? It seems irrelevant that all of the quill stems are different lengths due to the fact that I've tried tightening the various combinations of these components at different heights.

Thanks!
I'd guess that the Salsa stem is steel and the Specialized and Nitto stems are aluminum. I'd also guess that this allows the Salsa stem to expand a little further inside the steerer tube for the same tightening force on the binder screw.

Were all the stems torqued to the same degree? Were they all lubricated the same? Did the wedges all clamp at the same spot?
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Old 12-09-09, 12:28 AM
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Originally Posted by Jeff Wills View Post
I'd guess that the Salsa stem is steel and the Specialized and Nitto stems are aluminum. I'd also guess that this allows the Salsa stem to expand a little further inside the steerer tube for the same tightening force on the binder screw.

Were all the stems torqued to the same degree? Were they all lubricated the same? Did the wedges all clamp at the same spot?
Can we confirm with the OP whether the STEM is not being secured in the steertube or if the bar is not properly secured in the stem? I'm under the impression it's the latter.
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Old 12-09-09, 03:03 AM
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Originally Posted by operator View Post
Can we confirm with the OP whether the STEM is not being secured in the steertube or if the bar is not properly secured in the stem? I'm under the impression it's the latter.
+1
I'd also interpret the phrase "the drops shifting" as if it's the bar that's rotating in the stem rather than it's the stem sliding out of the steerer tube.
Then again, it's beyond me why anyone would believe that the height of the stem would influence the bar's resitance against rotating axially...

The phrase "nut" on a quill stem is a bit ambiguous. It can be the nut by the bar clamp, but it can also be the wedge at the bottom of the stem. And if it's the wedge they come in two different versions, one basically cylindrical but cut at an angle, one like a truncated cone(wich is rarer).
Swapping wedges(the cylindrical kind) between stems isn't as simple as it may seem. There's no defined standard for the angle of the cut(which has to match a corresponding angle at the stem) so swapping these between stems can easily result in a poor fit and poor clamping ability.
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Old 12-09-09, 03:16 AM
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OP is:
hugging the front tire between my legs
... when testing the stems, so I'm assuming he's turning the bars side-to-side.
Most stems will twist in this way if you really reef on them.
This may not be what actually caused the crash, mind you.
A loose bar-binder bolt could yield a catastrophic crash. This may be what the other rider actually described when he said:
(his) drops shifted
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Old 12-09-09, 06:11 AM
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So the theory stands as follows:
1) crash reason is bar rotated in the stem clasp, along its main axis
2) pre-ride testing of various fixes consists of attempts at twisting the quill stem around the steerer axis

Seems a bit odd. Might have to wait for the OP to come back with more info.
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Old 12-09-09, 06:28 AM
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I have many quill stem bikes, from high end custom made 20lbs road racing bikes to 40lbs Schwinn Typhoons, all of quill stems on them hold tight enough to damage the front wheel long before the stem rotates. I can't imagine what the issue is.

Edit, maybe the Schwinn steel rims will hold and allow the stem to rotate, not the alloy rimmed road bikes.
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Old 12-09-09, 10:05 AM
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One thing that always threw people off was the fact that the quill stem wedge bolt needs to be greased on the threads, the wedge nut should be greased where it slides/wedges against the stem and a thin layer of grease should be applied to outside surface of the stem and the wedge so that 1) it tightens properly and 2) doesn't sieze in the fork tube. Whenever people saw this at the bike shop I worked at they always asked "Won't that grease cause the stem to slide out?" No I had to answer it actually works the opposite it allows everything to tighten up quite nicely. That along with not inserting the stem to far down into the fork....
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Old 12-09-09, 10:20 AM
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Originally Posted by canopus View Post
...That along with not inserting the stem to far down into the fork....
Why is this an issue?
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Old 12-09-09, 10:35 AM
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Originally Posted by Mr IGH View Post
Why is this an issue?
Read post #2 up there ^^^
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Old 12-09-09, 10:37 AM
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Originally Posted by Mr IGH View Post
Why is this an issue?
If the fork is butted at the bottom and you try to insert the stem to far down into the fork you try to jam the quill stem into the butted portion of the steerer tube when it is tightened only a portion of the quill is doing its job and it could come loose from the butted tube and cause...well bad things to happen.

Illustration from Sheldon's site
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