Stem Bolt Failure - longish

Colin Marshall said:

Just a warning from a fellow cyclist. Solido/Soladio stem about 2 years
old, maybe 20,000km, no nasty accidents previously.

Just left a set of traffic lights, luckily, doing no more than about
10-15km when over the bars I went, lucky its was early so hardly any
traffic. Landed heavily on the head, yes wearing a helmet, looked at the
bike, to make sure it was OK, a Litespeed Siena, and saw the handlebars
hanging. Got up, very sore and moved myself across to the footpath.
Looked at the stem and noticed the bolts had broken off, only 2 but both
gone, so face plate came off and bars came off. 5 minutes earlier and it
would have been much worse, going down a ramp off a bridge doing about
40km instead!

Shoulder is stuffed, headache, lots of bruises and cuts. Bike seems to
be OK, got it to the shop and all looks good.

This is the second time I've had equipment failure, a few years ago the
handlebars snapped! Starting to get paranoid about bike equipment now.
Bike gets looked after and goes to the shop for a yearly check up,
usually after the winter.

So not sure how to keep this from happening, but alas will try and get
out on Monday for a ride, the old story about getting back on the horse.
BTW, there was a taxi going the other way with passengers, they had a
good laugh, glad someone was entertained anyway. Lady stopped to see how
I was, very nice of her, thanks.

Off to ponder what to do next about bike equipment.

Well if your longish stem bolt failed, maybe you should try a longer one?

:P.

Colin Marshall said:

This is the second time I've had equipment failure, a few years ago the
handlebars snapped! Starting to get paranoid about bike equipment now.
Bike gets looked after and goes to the shop for a yearly check up,
usually after the winter.

Glad you're mainly okay.

Equipment failure seems way too common with bikes. You don't hear about
this with cars very much. Even the cheapest and nastiest low end cars at
least seem to maintain basic structural integrity with minimal
maintenance.

What happened to you and what happened to dutcy recently I'd equate to a
car wheel snapping at the axle. It just doesn't happen very much, and
people get sued when it does.

--
..dt

bummer about your injuries.

Some light things just aren't worth the risk.

is this the stem?
http://www.cinelli.it/eng/bici/attacchi/ahead/SOLIDO.html

[img]cinelli.itsolido.jpgOpen ↗[/img]

Those stems came supplied with titanium bolts - the Solido that I bought did
anyway. The first thing I did was replace the titanium bolts with stainless
steel ones when I put it into use. I used the Ti bolts for the bottle
cages - if a bottle cage falls off the damage isn't so great.

Nick

"Colin Marshall" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Just a warning from a fellow cyclist. Solido/Soladio stem about 2 years
old, maybe 20,000km, no nasty accidents previously.

Just left a set of traffic lights, luckily, doing no more than about
10-15km when over the bars I went, lucky its was early so hardly any
traffic. Landed heavily on the head, yes wearing a helmet, looked at the
bike, to make sure it was OK, a Litespeed Siena, and saw the handlebars
hanging. Got up, very sore and moved myself across to the footpath. Looked
at the stem and noticed the bolts had broken off, only 2 but both gone, so
face plate came off and bars came off. 5 minutes earlier and it would have
been much worse, going down a ramp off a bridge doing about 40km instead!

Shoulder is stuffed, headache, lots of bruises and cuts. Bike seems to be
OK, got it to the shop and all looks good.

This is the second time I've had equipment failure, a few years ago the
handlebars snapped! Starting to get paranoid about bike equipment now.
Bike gets looked after and goes to the shop for a yearly check up, usually
after the winter.

So not sure how to keep this from happening, but alas will try and get out
on Monday for a ride, the old story about getting back on the horse. BTW,
there was a taxi going the other way with passengers, they had a good
laugh, glad someone was entertained anyway. Lady stopped to see how I was,
very nice of her, thanks.

Off to ponder what to do next about bike equipment.

a few years ago when quill stems were being lightened with alu wedge-bolts, I replaced them with steel bolts. I knew a big guy who busted one during a sprint, causing him to crash

531Aussie said:

bummer about your injuries.

Some light things just aren't worth the risk.

is this the stem?
http://www.cinelli.it/eng/bici/attacchi/ahead/SOLIDO.html

[image:
http://www.cinelli.it/snap/prodotti/attacchi/prodotto/solido.jpg]

Yup that's the one

Colin Marshall said:

Just a warning from a fellow cyclist. Solido/Soladio stem about 2 years
old, maybe 20,000km, no nasty accidents previously.

There's a theory going around that 2-3 years of regular use is
replaceme-o-clock for high-stress items like stems and bars,
if they're lightweight racing parts anyway.

Bike shops are going to struggle to tell you if it's about
to fail, they'd need xray equipment!

Gemma_k said:

"Bleve" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

There's a theory going around that 2-3 years of regular use is

replaceme-o-clock for high-stress items like stems and bars,
if they're lightweight racing parts anyway.

And some high-end stems come with specific instructions to replace all the
high-end fixings at certain intervals. I know 3Tdoes...

Quoted message said:

Bike shops are going to struggle to tell you if it's about
to fail, they'd need xray equipment!

I'm a nerdy engineering type - and I used to crack-test my racing
handlebars!! not too hard to do if you've got a crack testing kit!
So I've just switched to carbon...

What sort of kit would that be? I'm a (DNF) chem eng nerdy type,
didn't do much materials science - got as far as busting up
concrete in a press and writing gibberish prac reports to see if the
tutors
actually read them (they didn't read them ...)

Gemma_k said:

"Bleve" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

There's a theory going around that 2-3 years of regular use is

replaceme-o-clock for high-stress items like stems and bars,
if they're lightweight racing parts anyway.

And some high-end stems come with specific instructions to replace all the
high-end fixings at certain intervals. I know 3Tdoes...

Quoted message said:

Bike shops are going to struggle to tell you if it's about
to fail, they'd need xray equipment!

I'm a nerdy engineering type - and I used to crack-test my racing
handlebars!! not too hard to do if you've got a crack testing kit!
So I've just switched to carbon...

Hmmmmm I seem to remember that carbon cracks too 🙂

Bleve said:

Gemma_k said:

"Bleve" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

>There's a theory going around that 2-3 years of regular use is

replaceme-o-clock for high-stress items like stems and bars,
if they're lightweight racing parts anyway.

And some high-end stems come with specific instructions to replace all the
high-end fixings at certain intervals. I know 3Tdoes...

Quoted message said:

Bike shops are going to struggle to tell you if it's about
to fail, they'd need xray equipment!

I'm a nerdy engineering type - and I used to crack-test my racing
handlebars!! not too hard to do if you've got a crack testing kit!
So I've just switched to carbon...

What sort of kit would that be? I'm a (DNF) chem eng nerdy type,
didn't do much materials science - got as far as busting up
concrete in a press and writing gibberish prac reports to see if the
tutors
actually read them (they didn't read them ...)

There are dye kits for crack testing engine components. Use dye, Wipe
off, see crack with or without special light.

And the cheap method. Use oil on component. Wipe clean. Dust with
chalk. Cracks will show up as chalk lines.

Not foolproof tho

Kathy said:

Bleve wrote:

Quoted message said:

There are dye kits for crack testing engine components. Use dye, Wipe
off, see crack with or without special light.

And the cheap method. Use oil on component. Wipe clean. Dust with
chalk. Cracks will show up as chalk lines.

*nod*

Quoted message said:

Not foolproof tho

I wonder if from an LBS liability point of view, they'd be worth
doing? If the test isn't reliable - and it would be time
consuming - you'd have to pull the stem, the bars, the bartape,
levers etc off, root around for maybe an hour or so and then
not come up with a conclusive result either way unless there was
surface cracking? Would most cracks start at the outside surfaces?
And if so, would they then be so advanced that the failure was
imminent? I crank on my bars pretty hard (heavy roady sprinter)
and I'm always a bit worried that the [censored] things will bust off
in my hands one day at full tilt!

I'll talk to my mech-engie friends and see what they suggest 🙂

And a little more for carl..........

--- Cracking will most definately start at the surface
--- Crack testing is never 100% reliable - proof loading is more reliable
(but still not 100% - it will never simulate the real loading
conditions/environment)
--- The initation of fatigue cracks will occur after 95% of the cycles to
failure. The remaining 5% is crack growth. Failure will occur once you reach
a critical crack size for a given stress.

- Jimbo

"> > Not foolproof tho

Quoted message said:

I wonder if from an LBS liability point of view, they'd be worth
doing? If the test isn't reliable - and it would be time
consuming - you'd have to pull the stem, the bars, the bartape,
levers etc off, root around for maybe an hour or so and then
not come up with a conclusive result either way unless there was
surface cracking? Would most cracks start at the outside surfaces?
And if so, would they then be so advanced that the failure was
imminent? I crank on my bars pretty hard (heavy roady sprinter)
and I'm always a bit worried that the [censored] things will bust off
in my hands one day at full tilt!

I'll talk to my mech-engie friends and see what they suggest 🙂

Jimbo Jones said:

And a little more for carl..........

--- Cracking will most definately start at the surface
--- Crack testing is never 100% reliable - proof loading is more reliable
(but still not 100% - it will never simulate the real loading
conditions/environment)
--- The initation of fatigue cracks will occur after 95% of the cycles to
failure. The remaining 5% is crack growth. Failure will occur once you reach
a critical crack size for a given stress.

Cool. Thankyou. So basically (and this makes sense)
once cracks show up, the thing's rooted and will fail
pretty soon, or very soon if placed under excessive
stress?

Bleve said:

Cool. Thankyou. So basically (and this makes sense)
once cracks show up, the thing's rooted and will fail
pretty soon, or very soon if placed under excessive
stress?

Yup.

As a prime example: get out a note. Any note -- five dollar, ten dollar,
twenty, fifty, one hundred; doesn't matter. Try to tear it. Then cut a
very small slit in it and try to tear it again. Consider how much more
easily you can rip it the second time.

I would suggest that you make that slit near the corner, and in such a
direction that it's going to take the corner rather than the whole note,
by the way. 🙂

As soon as something starts to fail, that failure will extend through
the material. No ifs, buts, or maybes. How fast depends solely on how
much force is being exerted upon the material around the failure.

--
My Usenet From: address now expires after two weeks. If you email me, and
the mail bounces, try changing the bit before the "@ to usenet".

Bleve said:

Kathy said:

Bleve wrote:

Quoted message said:

There are dye kits for crack testing engine components. Use dye, Wipe
off, see crack with or without special light.

And the cheap method. Use oil on component. Wipe clean. Dust with
chalk. Cracks will show up as chalk lines.

*nod*

Quoted message said:

Not foolproof tho

I wonder if from an LBS liability point of view, they'd be worth
doing? If the test isn't reliable - and it would be time
consuming - you'd have to pull the stem, the bars, the bartape,
levers etc off, root around for maybe an hour or so and then
not come up with a conclusive result either way unless there was
surface cracking? Would most cracks start at the outside surfaces?
And if so, would they then be so advanced that the failure was
imminent?

YEah if you can see a crack failure is imminent... or so we used to
assume in car engines.

I crank on my bars pretty hard (heavy roady sprinter)

Quoted message said:

and I'm always a bit worried that the [censored] things will bust off
in my hands one day at full tilt!

I'll talk to my mech-engie friends and see what they suggest 🙂

Bleve said:

Jimbo Jones said:

And a little more for carl..........

--- Cracking will most definately start at the surface
--- Crack testing is never 100% reliable - proof loading is more reliable
(but still not 100% - it will never simulate the real loading
conditions/environment)
--- The initation of fatigue cracks will occur after 95% of the cycles to
failure. The remaining 5% is crack growth. Failure will occur once you reach
a critical crack size for a given stress.

Cool. Thankyou. So basically (and this makes sense)
once cracks show up, the thing's rooted and will fail
pretty soon, or very soon if placed under excessive
stress?

It will fail at the next availiable worse possible moment.

On 2005-09-26, dave (aka Bruce)
was almost, but not quite, entirely unlike tea:

Quoted message said:

Bleve said:

Cool. Thankyou. So basically (and this makes sense)
once cracks show up, the thing's rooted and will fail
pretty soon, or very soon if placed under excessive
stress?

It will fail at the next availiable worse possible moment.

What I've never understood about worst possible moments, is they are
local minima, so Murphy seeks out them naturally, and it will go for
the first one available.

But what if you have 2 worst-possible-moments, very close to each
other in time, but the second one is so much more worse than the first
one.

It will fail at the first one, and you will get the part replaced, and
while the part is being replaced, the opportunity for the second
worst-possible-moment has been and gone.

The paradox of Murphy's Law proven. QED.

--
TimC

Quoted message said:

aibohphobia, n., The fear of palindromes

And here I thought it was the fear of robotic Japanese dogs.
-- Tom "Tom" Harrington

TimC said:

On 2005-09-26, dave (aka Bruce)
was almost, but not quite, entirely unlike tea:

Quoted message said:

Bleve said:

Cool. Thankyou. So basically (and this makes sense)
once cracks show up, the thing's rooted and will fail
pretty soon, or very soon if placed under excessive
stress?

It will fail at the next availiable worse possible moment.

What I've never understood about worst possible moments, is they are
local minima, so Murphy seeks out them naturally, and it will go for
the first one available.

But what if you have 2 worst-possible-moments, very close to each
other in time, but the second one is so much more worse than the first
one.

It will fail at the first one, and you will get the part replaced, and
while the part is being replaced, the opportunity for the second
worst-possible-moment has been and gone.

Here you show your youthfullness young student

It will survive the first test. And allow you to sigh with relief
before failing at the second moment,

Quoted message said:

The paradox of Murphy's Law proven. QED.