Is this a death stem?
04-25-15 | 10:46 PM
#1
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Joined: Sep 2012
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From: Toronto, ON, Canada
Is this a death stem?
Seems to have just one slot at the expander, slot end is cut at an angle, no unusual wear patterns. There is a hole in the clamp area as you can see in the photos.
I am having a hard time finding a nice replacement 22.0 stem that will fit my existing handlebars (26.0 cinelli and a funny 25.2 Ava that came with this stem).
I am having a hard time finding a nice replacement 22.0 stem that will fit my existing handlebars (26.0 cinelli and a funny 25.2 Ava that came with this stem).
04-25-15 | 11:02 PM
#2
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Joined: Jul 2009
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Bikes: 1986 Alan Record Carbonio, 1985 Vitus Plus Carbone 7, 1984 Peugeot PSV, 1972 Line Seeker, 1986(est.) Medici Aerodynamic (Project), 1985(est.) Peugeot PY10FC
The slit for the wedge not having a round relieving hole at the top tells me it is, as that is where the crack happens that makes them death stems....
04-25-15 | 11:05 PM
#3
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From: Portland, OR
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
I don't know about that being a "death" stem but that exposed bolt can be a very unpleasant place to land. Not very different from the ubiquitous stems of the Peugeot UO-8. As a teenager, I approached a downhill intersection at speed, on the hoods with my fingers over the brake levers. I hit a rock I didn't see, lost my grip and landed sternum first on the bolt. Entered the intersection with my hands down by the front hub. No other injuries, but man, did my sternum hurt!
Ben
Ben
04-26-15 | 05:21 AM
#5
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Joined: Feb 2013
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From: Monkey Bottom, NC
Bikes: A bunch of old steel bikes + an ICE trike
See The Headbadge: Death Stems Demystified: AVA and ATAX for a fairly detailed description. Yours looks more like the "spearpoint" stem than the problem stem. Personally, I would drill a small relief hole at the top of the slot, deburr to get rid of sharp edges, and then use it. It appears that it has had very little use.
04-26-15 | 06:58 AM
#6
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Joined: Jan 2007
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Greetings
First the disclaimer: I am not an engineer, expert or in any way qualified to make a credible opinion as to the safety of any specific, group or category of bicycle stem or stems be they new, used or vintage of any material or method of fabrication or of any design. (I am also not a lawyer - please see "A Fish Called Wanda").
Be that as it may (I love the subjunctive), the following picture from Sheldon Brown, when he mentions "Death Stem", shows:
2 slits; one on the front and one on the back. Yours has 1.
From Brown and Rinard on testing failures, a summary:
"Most of the other failures were cracks in the quill tube, extension tube or the weld connecting these two tubes. Here's a sampling of the notes on failure modes:
Cracked in quill at bottom weld. Cracked in extension at quill. Welds polished around quill. Did not break.Cracked in quill, across weld.Cracked in quill, across weld.Quill cracked below bottom weld.Cracked along top of extension and on the compression side of quill weld.Cracked in quill, across weld.Cracked in extension at handlebar clamp. Across weld."Link: Stem Fatigue Testing, by Damon Rinard
The weld appears as a weak point which is no surprise. These were new stems.
John Allen explains a group of failures on the horizontal bit:
Hazardous bicycle handlebar stems i.e., design flaws you didn't think of.
Multiple other manufacturers made comparable stems with the same design (single slit) - Pivo, Philippe, Cinelli for a very long time. There are all kinds of anecdotes suggesting superlight aluminum stems have a higher failure.Lots of stories of new ones failing too.
w.r.t. your actual question: stress relief holes are put in at the time of manufacture, before micro failure has started. In adding one now, you may or may not drill out all of the fatigued zone (which may not be visible to the naked eye).
One final note, I think it was Jobst Brandt who didn't know his stem had broken until he removed it to change handlebars.
I hope this helps. Ultimately make your best decision for you.
r
First the disclaimer: I am not an engineer, expert or in any way qualified to make a credible opinion as to the safety of any specific, group or category of bicycle stem or stems be they new, used or vintage of any material or method of fabrication or of any design. (I am also not a lawyer - please see "A Fish Called Wanda").
Be that as it may (I love the subjunctive), the following picture from Sheldon Brown, when he mentions "Death Stem", shows:
2 slits; one on the front and one on the back. Yours has 1.
From Brown and Rinard on testing failures, a summary:
"Most of the other failures were cracks in the quill tube, extension tube or the weld connecting these two tubes. Here's a sampling of the notes on failure modes:
Cracked in quill at bottom weld. Cracked in extension at quill. Welds polished around quill. Did not break.Cracked in quill, across weld.Cracked in quill, across weld.Quill cracked below bottom weld.Cracked along top of extension and on the compression side of quill weld.Cracked in quill, across weld.Cracked in extension at handlebar clamp. Across weld."Link: Stem Fatigue Testing, by Damon Rinard
The weld appears as a weak point which is no surprise. These were new stems.
John Allen explains a group of failures on the horizontal bit:
Hazardous bicycle handlebar stems i.e., design flaws you didn't think of.
Multiple other manufacturers made comparable stems with the same design (single slit) - Pivo, Philippe, Cinelli for a very long time. There are all kinds of anecdotes suggesting superlight aluminum stems have a higher failure.Lots of stories of new ones failing too.
w.r.t. your actual question: stress relief holes are put in at the time of manufacture, before micro failure has started. In adding one now, you may or may not drill out all of the fatigued zone (which may not be visible to the naked eye).
One final note, I think it was Jobst Brandt who didn't know his stem had broken until he removed it to change handlebars.
I hope this helps. Ultimately make your best decision for you.
r
Last edited by raymond1354; 04-26-15 at 07:00 AM. Reason: signature
04-26-15 | 06:11 PM
#8
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Joined: Jan 2015
Posts: 117
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From: Ontario Canada
Bikes: mostly old steel 70's 80's 90's
If you are considering going through the trouble of drilling a relief hole, removing burrs and such, you should also think of glass bead blasting the stem. The glass bead process is much like "shot peening" and relieves the surface tension on metal. I think that these stems should be OK for people who know how to heed the warning signs.
04-26-15 | 06:49 PM
#9
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Joined: Mar 2014
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From: Hopkinton, MA
Bikes: 1938 Raleigh Record Ace (2), 1938 Schwinn Paramount, 1961 Torpado, 1964? Frejus, 1980 Raleigh 753 Team Pro, Moulton, other stuff...
If it's a cast stem (one can tell by the fine lines at the mold parting) IMOO DON'T use it.
