safest stem?

Mike Jacoubowsky said:

Quoted message said:

Quoted message said:

> Seems to me that a stem is a good place to use some steel that's less
> brittle than aluminum. Salsa makes a steel threadless stem that costs
> about $40USD. Very nice stuff. Then again, I've got a stupid amount of
> miles on aluminum stems without failure. Maybe I'm just not man enough
> to wrench it apart. :sigh:
Dude was riding a Fuji track bike, geared at 53x13 (in Atlanta's rolling
terrain). He was sprinting up a hill (faster than anyone around him,
mind you) and then this happened:
http://tinyurl.com/ycdg73
http://tinyurl.com/ydlwa7

which is why i say stick to single-piece cold forged stems! [apart from
the clamp of course.]

You mean like the one I had fail? It was a Mavic forged aluminum stem, and
the bottom part of the handlebar clamp, where the tightening bolt threaded
into, simply pulled away from the rest of the stem.

got a pic? not many people cold forge - it costs more. i've not seen
this mavic stem, but if the material was good, theres still no guarantee
the design was right - need design /and/ material.

Quoted message said:

The threads didn't
strip, but rather the section the threads were in just separated. I replaced
that with an Ibis titanium stem; the handlebar pinch bolt broke on that one
(and during a sprint, no less... why I didn't go down is completely beyond
me).

Now I've got a massively-big & sorta ugly Bontrager carbon stem, which would
probably take a chainsaw to kill. 140 grams, which is about 40 grams heavier
than some of the modern ultralight aluminum stems these days. Yeah, it would
be nicer if they'd engineer something a bit lighter, but it's also nice that
I don't worry about stem failures anymore.

actually, carbon can be great in that respect - much less fatigue. the
issue with a stem is whether it's one of the on-piece items and built
appropriately or whether it's bonded to aluminum ends like some of the
poor designs are. i'd not bother with the latter.

the ultimate in old quill stems was nitto, imo. beautiful cold forging
of the very highest quality.

Quoted message said:

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

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

Quoted message said:

Paul Hobson said:

landotter wrote:
> Callistus Valerius wrote:
>> What would be the safest threadless road stem out there, with a face
>> plate
>> so you don't have to remove the shifters etc? Of all the bike
>> components, I
>> always look at the stem as the most scary, as a failure would be
>> catastrophic. I've seen lots of metal [censored] break that looked a hell of
>> a
>> lot stronger than a bicycle stem, thus the paranoia. I've ridden
>> around a
>> 100,000 miles and never had a failure, and I have had two bolt and 4
>> bolt
>> stems, and never a failure or a crack in any of them. But is there
>> such a
>> thing as a fail-safe one, with the specs I listed?
> Seems to me that a stem is a good place to use some steel that's less
> brittle than aluminum. Salsa makes a steel threadless stem that costs
> about $40USD. Very nice stuff. Then again, I've got a stupid amount of
> miles on aluminum stems without failure. Maybe I'm just not man enough
> to wrench it apart. :sigh:
Dude was riding a Fuji track bike, geared at 53x13 (in Atlanta's rolling
terrain). He was sprinting up a hill (faster than anyone around him,
mind you) and then this happened:
http://tinyurl.com/ycdg73
http://tinyurl.com/ydlwa7

which is why i say stick to single-piece cold forged stems! [apart from
the clamp of course.]

Quoted message said:

Paul Hobson said:

Dude was riding a Fuji track bike, geared at 53x13 (in Atlanta's rolling
terrain). He was sprinting up a hill (faster than anyone around him,
mind you) and then this happened:
http://tinyurl.com/ycdg73
http://tinyurl.com/ydlwa7

Looking at the first picture, the fracture surface that is closest to
the table, on both the quill and the extension, looks dark. If you
put the stem back together and looked at it from the front of the
bike, the area I'm talking about would be at 3 to 5 o'clock. If this
is not a trick of the light, it suggests there was already a fairly
substantial crack in the stem before the final separation.

that's the truth! it's most unlikely all that cracking happened
immediately - regular visual inspection should have caught it.

Quoted message said:

Something about the way the exposed crack surface on the quill
doesn't touch the quill tube makes me wonder if the extension was
mitered carefully to fit onto the quill, although maybe it was and
the mitered surface is all hidden under the weld.

that may be true, but one of the obvious issues is very poor melt depth
- the weld pool is largely cosmetic. but even /that/ is academic - the
cracking is not in the weld, but the heat affected zone of the
extension, and well beyond. cheap cheesy garbage. i don't have any
welded stems.

Callistus Valerius said:

What would be the safest threadless road stem out there, with a face plate
so you don't have to remove the shifters etc? Of all the bike components, I
always look at the stem as the most scary, as a failure would be
catastrophic. I've seen lots of metal [censored] break that looked a hell of a
lot stronger than a bicycle stem, thus the paranoia. I've ridden around a
100,000 miles and never had a failure, and I have had two bolt and 4 bolt
stems, and never a failure or a crack in any of them. But is there such a
thing as a fail-safe one, with the specs I listed?

100,000 miles?

Various people, companies offer custom stems. You could have an extra
solid one built just for you. Would not be the cheapest stem around.
But I reckon you could spec about any thickness of steel you want.
Extra gussetts, braces, etc.

Clive George said:

Detatching the handlebars doesnt' necessarily cause brake loss. Ok, it's
probably not going to be easy when you're not ready for it, and drops will
be harder than flats, but I did once ride a bike home with brakes but no
steering - you just hold the bars and remember that moving them doesnt'
achieve anything :-)

If you are braking and don't have something to keep you on the bike,
like your hands on the bars, you effectively have no brakes.
-------------------
Alex

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

Quoted message said:

Clive George said:

Detatching the handlebars doesnt' necessarily cause brake loss. Ok, it's
probably not going to be easy when you're not ready for it, and drops
will
be harder than flats, but I did once ride a bike home with brakes but no
steering - you just hold the bars and remember that moving them doesnt'
achieve anything :-)

If you are braking and don't have something to keep you on the bike,
like your hands on the bars, you effectively have no brakes.

You've tried it, have you? Granted, it's harder than with properly attached
bars. But did you know some unicycles have brakes?

clive

Callistus Valerius said:

What would be the safest threadless road stem out there, with a face plate
so you don't have to remove the shifters etc? Of all the bike components, I
always look at the stem as the most scary, as a failure would be
catastrophic. I've seen lots of metal [censored] break that looked a hell of a
lot stronger than a bicycle stem, thus the paranoia. I've ridden around a
100,000 miles and never had a failure, and I have had two bolt and 4 bolt
stems, and never a failure or a crack in any of them. But is there such a
thing as a fail-safe one, with the specs I listed?

There's some old stem fatigue test data here:
http://www.damonrinard.com/stemtesting.htm

On Thu, 4 Jan 2007 17:05:46 -0000, "Clive George"
<[email hidden]> wrote:

[snip]

Quoted message said:

But did you know some unicycles have brakes?

clive

Dear Clive,

Some unicycles have brakes? I'm fascinated!

I assume that they're not parking brakes. 🙂

My vague impression was that unicycles are fixies and go so slowly and
precariously that they need nothing but leg braking.

Oodles of details about unicycles speed and braking would be nice, or
even just a link. I don't expect videos of unicycles laying down
skidmarks, but this sounds like fun.

Cheers,

Carl Fogel

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

Quoted message said:

Clive George said:

But did you know some unicycles have brakes?

Some unicycles have brakes? I'm fascinated!

I assume that they're not parking brakes. 🙂

Yup.

Quoted message said:

My vague impression was that unicycles are fixies and go so slowly and
precariously that they need nothing but leg braking.

Pretty much. But there are exceptions.

Quoted message said:

Oodles of details about unicycles speed and braking would be nice, or
even just a link. I don't expect videos of unicycles laying down
skidmarks, but this sounds like fun.

I've heard of them being used on munis and cokers (large wheeled road ones)
to relieve pressure on knees during descents. Google for unicycle brake
should get you as much info as I can.

cheers,
clive

Quoted message said:

On Thu, 4 Jan 2007 17:05:46 -0000, "Clive George"
<[email hidden]> wrote:

[snip]

Quoted message said:

But did you know some unicycles have brakes?

Quoted message said:

Some unicycles have brakes? I'm fascinated!
I assume that they're not parking brakes. 🙂

My vague impression was that unicycles are fixies and go so slowly and
precariously that they need nothing but leg braking.

Oodles of details about unicycles speed and braking would be nice, or
even just a link. I don't expect videos of unicycles laying down
skidmarks, but this sounds like fun.

http://www.fixedgeargallery.com/2006/dec/JacobKnable.htm

As you can see, the is attached to the seat of the unicycle. IMO, this
doesn't helps Clive's claim that you don't need the brakes to be
attached to a fixed point in order to work.

However, intuitively, I feel that a free floating, hand brake could
work, it would just have to be used very delicately so that you
decelerate at the same rate as the bike. I think this comes from the
tine I rode my fixie home from the store with bags in each hand, and
slowed down the bike (not to a full stop) while riding no handed using
only back pressure on the pedals.
\\paul

jobst.brandt said:

Callistus Valerius said:

What would be the safest threadless road stem out there, with a face
plate so you don't have to remove the shifters etc? Of all the bike
components, I always look at the stem as the most scary, as a failure
would be catastrophic. I've seen lots of metal [censored] break that looked
a hell of a lot stronger than a bicycle stem, thus the paranoia. I've
ridden around a 100,000 miles and never had a failure, and I have had
two bolt and 4 bolt stems, and never a failure or a crack in any of
them. But is there such a thing as a fail-safe one, with the specs I
listed?

For non-quill stems, I would consider only ones with redundancy, such as
four bolt clamp plate and two stem clamp bolts. Without that one bolt
failure leaves the bicycle with a detached handlebar. In other words,
neither steering nor brakes. Not a recoverable situation considering
that such a bolt failure would be occurring at a stressful instant.

Thomson stems have four handlebar clamp bolts but use a different design
for the steerer clamp -- I don't know what to call it but my Syncros stem
has the same design. There's no redundancy but I'm not sure it's needed.

The stems on my two bikes have just two handlebar clamp bolts but they're
both at the bottom, the top being held by a hinge on one (Syncros), and
interlocking/captured on the other (Klein MC3). This seems OK in case a
single bolt fails, and it eliminates the problem of upper and lower bolts
not being torqued evenly.

However stems do fail in places other than at the bolts, and we have no
way of knowing the good ones from the bad without published tests. Damon
Rinard did such a test several years ago, but most of the stems he tested
are probably no longer available. Even if they're the same product in
name, they may be totally different.

OEM stems from major companies like Trek (ie, Bontrager) are probably a
good bet. These companies are concerned about liability, and have the
engineering and quality control resources to ensure safe products.

As with many things bike, I chose my stems because they were the only ones
available in the size I wanted that fit. If I had other options I might
have chosen differently.

Matt O.

Chalo said:

Callistus Valerius wrote:

Quoted message said:

Quoted message said:

What would be the safest threadless road stem out there, with a face plate
so you don't have to remove the shifters etc?

Quoted message said:

Thomson Elite is the strongest, most proven stem for its weight that I
know of.

Proven how? It looks good to me too, but...

Matt O.

Quoted message said:

100,000 miles?

Various people, companies offer custom stems. You could have an extra
solid one built just for you. Would not be the cheapest stem around.
But I reckon you could spec about any thickness of steel you want.
Extra gussetts, braces, etc.

-----
I average around 15,000 miles a year (300/week). Since I started riding, I
logged my miles. I got into cycling for fitness, so logging miles just
seemed the thing to do. Then I just got into riding, but never got out of
the habit of logging the monthly totals off the computers of the three road
bikes I ride. I do minimal mountain biking, maybe 800 miles a year that are
not included in that figure, as I think they are two different things. I
live in Arizona so I ride all year, and probably only log 4 hours on the
rollers in a whole year.

Clive George said:

Quoted message said:

For non-quill stems, I would consider only ones with redundancy,
such as four bolt clamp plate and two stem clamp bolts. Without
that one bolt failure leaves the bicycle with a detached handlebar.
In other words, neither steering nor brakes. Not a recoverable
situation considering that such a bolt failure would be occurring
at a stressful instant.

Quoted message said:

Detatching the handlebars doesnt' necessarily cause brake loss. Ok,
it's probably not going to be easy when you're not ready for it, and
drops will be harder than flats, but I did once ride a bike home
with brakes but no steering - you just hold the bars and remember
that moving them doesnt' achieve anything :-)

Visualize hands grasping the handlebar and one of two bar clamp screws
failing. The handlebar is free in the air with brake cables attached.
How does the rider move his hands onto the brake levers and how does
he apply the brakes? I don't think your experience occurred as bars
suddenly becoming detached while traveling over road hazards great
enough to initiate such a failure.

Jobst Brandt

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

Quoted message said:

Clive George said:

Quoted message said:

For non-quill stems, I would consider only ones with redundancy,
such as four bolt clamp plate and two stem clamp bolts. Without
that one bolt failure leaves the bicycle with a detached handlebar.
In other words, neither steering nor brakes. Not a recoverable
situation considering that such a bolt failure would be occurring
at a stressful instant.

Quoted message said:

Detatching the handlebars doesnt' necessarily cause brake loss. Ok,
it's probably not going to be easy when you're not ready for it, and
drops will be harder than flats, but I did once ride a bike home
with brakes but no steering - you just hold the bars and remember
that moving them doesnt' achieve anything :-)

Visualize hands grasping the handlebar and one of two bar clamp screws
failing. The handlebar is free in the air with brake cables attached.
How does the rider move his hands onto the brake levers and how does
he apply the brakes?

I feel you're making elementary mistakes, like not reading what I wrote. He
moves his fingers onto the brake levers exactly as he would if the handlebar
were attached to the bike. I did say flats would be a lot easier - your
hands could well be in the right position already. With drops, it would
probably only work from the drops rather than the hoods.

Quoted message said:

I don't think your experience occurred as bars
suddenly becoming detached while traveling over road hazards great
enough to initiate such a failure.

I don't think you're being helpful here. What I said happened, happened. I'm
neither lying nor mistaken. (and your sentence doesn't actually parse...)

I intended a vaguely hunerous anecdote - I even put a smiley on to help
those who are a bit impaired in this department. You have gone on the
attack, basically accusing me of lying. I consider that offensive. If you
want, we can carry on this discussion in a civilised manner - but you will
first have to withdraw your accusation. Your move.

clive

Matt O'Toole said:

Quoted message said:

Thomson Elite is the strongest, most proven stem for its weight that I
know of.

Proven how? It looks good to me too, but...

I've heard it has been proof tested to over 3000 lbs. of vertical load.

As far as I can tell, it is the long-term favorite stem among
downhillers, whose other long-term favorite parts tend to be strong but
heavy.

Chalo

jim beam wrote:
the ultimate in old quill stems was nitto, imo. beautiful cold forging

Quoted message said:

of the very highest quality.

I thought so too until mine broke. It is the only stem I've ever had
break...

Quoted message said:

Visualize hands grasping the handlebar and one of two bar clamp
screws failing. The handlebar is free in the air

....after the second screw failed as well. Before that it is free to
rotate but not free to move. Good question how long the second
screw will withstand the bending force.

--
MfG/Best regards
helmut springer

Yeah, I was going to question that as well. Thanks for making it easy
Chalo. They say "twice as strong in fatigue as other models tested".
Theirs is steel alloy, so they could have picked all 'single nut' 'AL
clamp' posts. Duh, twice as strong.

In fact if I didn't need a seatpost shim to make it work, I was
consdering buying one. But am happy with my $10 Kalloy machined AL with
new $5 dual nut steel bracket, which was easy to cut down to size and
grind edges smooth. Thompsons are nicer with brackets included, but
they are not giving anything away. They are about as expensive as you
can get, except for the plastic carbon ones.

But when a company implies stronger, its from the metal samples/clamp
configurations they tested. Metal is metal, and that's a lot of what
you're paying for: generalized advertising that makes you feel good.
Metal is either cast/machined or forged. Forged is stronger, but also
expands and contracts more with temperature, and is not as uniform
material for altering later. If Thomson has a special metal
formulation, then they should state it. They should include sample
product comparison data and measures as well if not just blowing smoke.
Except for Chinese metals not processed to required grade
certifications, metal grades are metal grades. Some are purtier than
others.

But for one piece clamp/posts, they have all the requirements for easy
road adjustments with allen screw. I just wouldn't want to cut one down
and sand it smooth: it would just take a little longer.

imo

Chalo said:

Matt O'Toole said:

Quoted message said:

Thomson Elite is the strongest, most proven stem for its weight that I
know of.

Proven how? It looks good to me too, but...

I've heard it has been proof tested to over 3000 lbs. of vertical load.

As far as I can tell, it is the long-term favorite stem among
downhillers, whose other long-term favorite parts tend to be strong but
heavy.

Chalo

Oh yeah, Seat posts were what I was considering, but same difference
in all respects to stems.
Thompson makes high quality, high dollar reliable products that are
over marketed with verifiable evidence lacking: which I think is a
percentage of what you are paying for.

They may be over specified materials in their 'steel alloy', which may
be good for off roaders.
But I'd still consider one, as its one of the better products in
features if you have a popular size.

But it would have to be cost beneifted on known features I can verify:
not touchy feely descriptions.

imo

ddog said:

Yeah, I was going to question that as well. Thanks for making it easy
Chalo. They say "twice as strong in fatigue as other models tested".
Theirs is steel alloy, so they could have picked all 'single nut' 'AL
clamp' posts. Duh, twice as strong.

In fact if I didn't need a seatpost shim to make it work, I was
consdering buying one. But am happy with my $10 Kalloy machined AL with
new $5 dual nut steel bracket, which was easy to cut down to size and
grind edges smooth. Thompsons are nicer with brackets included, but
they are not giving anything away. They are about as expensive as you
can get, except for the plastic carbon ones.

But when a company implies stronger, its from the metal samples/clamp
configurations they tested. Metal is metal, and that's a lot of what
you're paying for: generalized advertising that makes you feel good.
Metal is either cast/machined or forged. Forged is stronger, but also
expands and contracts more with temperature, and is not as uniform
material for altering later. If Thomson has a special metal
formulation, then they should state it. They should include sample
product comparison data and measures as well if not just blowing smoke.
Except for Chinese metals not processed to required grade
certifications, metal grades are metal grades. Some are purtier than
others.

But for one piece clamp/posts, they have all the requirements for easy
road adjustments with allen screw. I just wouldn't want to cut one down
and sand it smooth: it would just take a little longer.

imo

Chalo said:

Matt O'Toole said:

> Thomson Elite is the strongest, most proven stem for its weight that I
> know of.

Proven how? It looks good to me too, but...

I've heard it has been proof tested to over 3000 lbs. of vertical load.

As far as I can tell, it is the long-term favorite stem among
downhillers, whose other long-term favorite parts tend to be strong but
heavy.

Chalo

ddog said:

Oh yeah, Seat posts were what I was considering, but same difference
in all respects to stems.
Thompson makes high quality, high dollar reliable products that are
over marketed with verifiable evidence lacking: which I think is a
percentage of what you are paying for.

I haven't tuned in to any media featuring bike industry ads (except the
websites of bike manufacturers and retailers) since the mid-'90s. I
have never seen Thomson advertise or sponsor any of the bike-related
events I have attended during the same time. So I have to take your
word for it that Thomson products are heavily marketed. What I've
noted is that they have won the loyalty of many of the riders I know
who break stuff.

I can't speak from direct experience about Thomson stems, because I
haven't used one. I have used Thomson seatposts, though, and they have
a distinction: They are the only seatposts I've ever tried that I can
extend more than about 25cm without bending. I don't ride on harsh
surfaces, I don't jump my bike; but I do weigh about 375 lbs and
measure 6'8". I've had cause to try many a long seatpost, and I've
bent all of them except those of two manufacturers-- L. H. Thomson and
myself. Mine don't bend because I make them of very thick pieces of
the strongest materials I can get my hands on. Typically I use 7075
aluminum, and I use wall thicknesses from 5mm on up to solid rod.

I've bent SR Laprade posts, guaranteed IRD Racing posts, welded
chromoly posts, straight chromoly posts, even 3mm thick seamless
chromoly tubing I bought in the pursuit of a stronger, longer seatpost.
Thomson posts have never bent on me, even the 410mm length when
extended to near its limit.

Quoted message said:

They may be over specified materials in their 'steel alloy',

They don't use steel alloy except in their annoyingly proprietary
bolts. The posts and stems are made of 7075 aluminum. The seatposts
use a forging which is machined to net size. Since I have not seen
claims that the stems are machined from forgings, I assume that they
are machined from billet.

Quoted message said:

But it would have to be cost beneifted on known features I can verify:
not touchy feely descriptions.

http://lhthomson.com/elite_features.htm

You can believe these claims or not, but there are assertions here that
come with units attached, and that can be tested. The most specific
strength claim is as follows:

"The Thomson seatpost has a clamp, head, and upper tube strong enough
to withstand 350 foot-lbs of torque. The tube will start to yield and
bend at the seat tube clamp at about 250 foot-lbs of torque."

I've not performed any controlled tests on my Thomson seatposts, but
they have succeeded on a pass/fail basis where others have failed.

Chalo