safest stem?
Callistus Valerius
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 sh*t 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?
landotter
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:
jim beam
be real safe. replace handlebars at the same time. use o/s
stem/handlebars of the highest quality you can afford too if you want to
be even safer. cold forged.
David L. Johnson
So, you have all this personal experience with the reliability of these
stems, but yet you are paranoid about them braking? Yes, I know that
stems have been known to break, and sometimes without the rider being
aware until it failed catastrophically. But this is a rare occurrence.
Certainly seat post failures are more common, and painful to contemplate.
Are you as paranoid about those? Forks can fail, cranks, etc. Usually
there are warning signs, if you will look for them. Do that, or give up
the sport as being too dangerous.
I sincerely doubt that there is a single stem that is unbreakable. Yes,
steel would be less likely to fail without obvious warnings, but then you
should also use steel cranks, seatposts, and forks by that logic.
Certainly cost does not correlate with failure risk, in fact some of the
most expensive are expensive precisely because they are lighter, hence
weaker.
Stuff happens, but it happens less if you watch for signs of cracking, and
listen for new creaks and other unusual noises. And yes, a broken stem can
cause a fall. But you can fall with a perfectly sound bike as well.
Relax and enjoy the ride.
--
David L. Johnson
__o | Do not worry about your difficulties in mathematics, I can
_`\(,_ | assure you that mine are all greater. -- A. Einstein
(_)/ (_) |
Kurd
"Callistus Valerius" <jazz...@hotmail.com> wrote in message
news:1H_mh.7056$yx6....@newsread2.news.pas.earthlink.net...
Probably something sexy and practical like this, available from any local
bike shop with a QBP catalog:
http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=SM9252
/sarcasm
Paul Hobson
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
\\paul
jobst....@stanfordalumni.org
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.
Jobst Brandt
landotter
Paul Hobson wrote:
>
> Dude was riding a Fuji track bike, geared at 53x13 (in Atlanta's rolling
> terrain).
Slightly less steep than our Nashville hills, but still--that's a nutso
gear on the street. I ride 42x15 fixed around here and moan that I
gotta get a 16. Now I really feel inadequate. ;-)
>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
That looks like an absolute crap weld in the first place! Scary! I've
never had anything major break on a bike. [/me knocks on desk]
***
off topic:
While I got your attention, what's a good and fairly cheap place to
grab eats in Atlanta that's got some local flair? I'll be passing
through this spring and staying over by that new IKEA store.
Traditional southern is nice, but if there's international cuisine of
merit in the area, that's my cuppa as well. Hole in the wall sorta
place is preferred, and if it's just a shack with a window and a Coke
machine then it'll likely get 5 landotter stars! I'll eat anything from
decent vegetarian (hold the sprouts) to pork cracklins.
Shame I won't have room for a bike in the car, I'd have hooked up with
ya for a fixie tour de 'lanta. Five people in a Jetta, this should be
fun...
jim beam
the clamp of course.]
Paul Hobson
> Paul Hobson wrote:
>
>> Dude was riding a Fuji track bike, geared at 53x13 (in Atlanta's rolling
>> terrain).
>
> Slightly less steep than our Nashville hills, but still--that's a nutso
> gear on the street. I ride 42x15 fixed around here and moan that I
> gotta get a 16. Now I really feel inadequate. ;-)
He's since switched to 48x15 having learned the benefits of a higher
cadence (shakes head)
>> 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
>
> That looks like an absolute crap weld in the first place! Scary! I've
> never had anything major break on a bike. [/me knocks on desk]
Yeah. That was our assessment as well. Still, dude's an animal. He's
about 5' 9" - 10". Slender and not much taller than me...but massive
legs. He also lives off of coffee, candy, and the occasional beer.
> ***
> off topic:
>
> While I got your attention, what's a good and fairly cheap place to
> grab eats in Atlanta that's got some local flair? I'll be passing
> through this spring and staying over by that new IKEA store.
Ah, my old side of town (still where I commute to everyday).
> Traditional southern is nice, but if there's international cuisine of
> merit in the area, that's my cuppa as well. Hole in the wall sorta
> place is preferred, and if it's just a shack with a window and a Coke
> machine then it'll likely get 5 landotter stars! I'll eat anything from
> decent vegetarian (hold the sprouts) to pork cracklins.
Trad. Southern:
-Bobby & June Country Kitchen on 14th St between Mecaslin St and State
St (this is right next to Atlantic Station/IKEA)
-Son's Place at Hurt St and Decatur Ave
Vegan/Black Hebrew Southern:
-Soul Vegetarian No. 2 on N. Highland between Ponce de Leon and North
Ave (a little pricey, but good!)
*Authentic* _Cuban_ sandwiches
-Kool Korner's on 14th and State St (*hole* in wall, take out only, but
damn good at $4.70 a piece after tax).
As a last resort, go to Eat's on Ponce. Bobby and June's is probably
right up your alley and damn close to where you'll be. The hours are
shifted kind of early (6am - 2pm?), so you definitely need to be there
by not long after "lunchtime." It's pretty busy, but you tend get
seated fairly quickly. I prefer Son's personally as it's more 'Soul'
food than 'Southern' (shades of gray, really), but much less convenient
to find. Also, if you end up spending too much money at IKEA, eat
there. It's dirt cheap and pretty alright too.
> Shame I won't have room for a bike in the car, I'd have hooked up with
> ya for a fixie tour de 'lanta. Five people in a Jetta, this should be
> fun...
Question: how are you going to be getting anything home? I'm a student
a GA Tech (a few blocks from AS/IKEA), drop me a buzz off line for a
phone number if you get lost/whatever. (switch the words to numbers)
\\paul
Mike Jacoubowsky
>>> 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. 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.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"jim beam" <spamv...@bad.example.net> wrote in message
news:0radnecb584IDAHY...@speakeasy.net...
Chalo
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?
Thomson Elite is the strongest, most proven stem for its weight that I
know of.
landotter
Paul Hobson wrote:
> Ah, my old side of town (still where I commute to everyday).
>
> > Traditional southern is nice, but if there's international cuisine of
> > merit in the area, that's my cuppa as well. Hole in the wall sorta
> > place is preferred, and if it's just a shack with a window and a Coke
> > machine then it'll likely get 5 landotter stars! I'll eat anything from
> > decent vegetarian (hold the sprouts) to pork cracklins.
>
> Trad. Southern:
> -Bobby & June Country Kitchen on 14th St between Mecaslin St and State
> St (this is right next to Atlantic Station/IKEA)
> -Son's Place at Hurt St and Decatur Ave
>
I've heard great stuff about Son's! I'm a greens lover, so we'll see if
they stack up to Nashville's Swett's.
> Vegan/Black Hebrew Southern:
> -Soul Vegetarian No. 2 on N. Highland between Ponce de Leon and North
> Ave (a little pricey, but good!)
Sounds crazy! On the short list. Who doesn't love
Vegan/Black/Hebrew/Southern cuisine? LOL My passengers are semi-veg
Swedish salon-commies, so they'll probably pass out from the
authenticity.
>
> *Authentic* _Cuban_ sandwiches
> -Kool Korner's on 14th and State St (*hole* in wall, take out only, but
> damn good at $4.70 a piece after tax).
That is the thing I'm talkin' about! Yeah!
>
> As a last resort, go to Eat's on Ponce. Bobby and June's is probably
> right up your alley and damn close to where you'll be. The hours are
> shifted kind of early (6am - 2pm?), so you definitely need to be there
> by not long after "lunchtime." It's pretty busy, but you tend get
> seated fairly quickly. I prefer Son's personally as it's more 'Soul'
Know zaktly what you're talking about. Son's is the top of the list.
> food than 'Southern' (shades of gray, really), but much less convenient
> to find. Also, if you end up spending too much money at IKEA, eat
> there. It's dirt cheap and pretty alright too.
Har, I've eaten at half a dozen IKEA's. The food is actualy quite
spectacular for the money. I'm a Swede and was chagrined when I got the
meatball special in 'lanta last time. Tasted just like in Gothenburg.
:D
>
> > Shame I won't have room for a bike in the car, I'd have hooked up with
> > ya for a fixie tour de 'lanta. Five people in a Jetta, this should be
> > fun...
>
> Question: how are you going to be getting anything home? I'm a student
> a GA Tech (a few blocks from AS/IKEA), drop me a buzz off line for a
> phone number if you get lost/whatever. (switch the words to numbers)
> \\paul
Not there for shopping, Paul, just that I'm having relatives fly over
from Swedeland. We'll be sending them off and welcoming them in Memphis
and Atlanta to save some bucks. Got some killer hotel discounts from a
friend of my momma's so we can make the pickup and dropoff points a bit
of a party.
Thanks so much for the recommendations, Paul! More than I could ever
have found on those internet tubes. May the Flying Spaghetti Monster
annoint you!
-Max in Nashville
b...@mambo.ucolick.org
> 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.
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.
Ben
Kenny
landotter wrote:
>
>
> While I got your attention, what's a good and fairly cheap place to
> grab eats in Atlanta that's got some local flair?
Waffle House?
Tim McTeague
ddog
http://www.nashbar.com/profile.cfm?sku=10679&PID=1204522
Above looks like $79 Oval stem but only $20. Blindly buying fixed stems
after another seems stupid to me. But need stem adapter, stem, bars,
and tape ($59 + shipping from 2 places).
This is not spam, but the result of hours of stem research :-)
Thanks!!
John Forrest Tomlinson
I think you should use whatever you currently use, but replace it
regularly -- perhap every 50K or 80K miles.
That said, I'd speculate Salsa steel stems and lower-end Ritchey stems
are particularly durable.
--
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************
Qui si parla Campagnolo
Ritchey Comp or Salsa steel one.
Clive George
news:459c90a0$0$80056$742e...@news.sonic.net...
> 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.
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 :-)
cheers,
clive
jim beam
>>>> 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.
> 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.
jim beam
> Paul Hobson wrote:
>
>> 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.
>
> 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.
russell...@yahoo.com
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.
Alex
Clive George wrote:
> 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
Clive George
news:1167930178....@11g2000cwr.googlegroups.com...
You've tried it, have you? Granted, it's harder than with properly attached
bars. But did you know some unicycles have brakes?
clive
almos...@yahoo.com
There's some old stem fatigue test data here:
http://www.damonrinard.com/stemtesting.htm
carl...@comcast.net
<cl...@xxxx-x.fsnet.co.uk> wrote:
[snip]
> 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
Clive George
news:3hhqp25f6p7bcblss...@4ax.com...
> On Thu, 4 Jan 2007 17:05:46 -0000, "Clive George"
> <cl...@xxxx-x.fsnet.co.uk> wrote:
>
>> But did you know some unicycles have brakes?
>
>
> I assume that they're not parking brakes. :)
Yup.
> 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.
> 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
Paul Hobson
> On Thu, 4 Jan 2007 17:05:46 -0000, "Clive George"
> <cl...@xxxx-x.fsnet.co.uk> wrote:
>
> [snip]
>
>> But did you know some unicycles have brakes?
carl...@comcast.net wrote:
> 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
Matt O'Toole
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.
Matt O'Toole
Proven how? It looks good to me too, but...
Matt O.
Crescentius Vespasianus
>
> 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.
jobst....@stanfordalumni.org
>> 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.
> 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
Clive George
news:459d5f21$0$80066$742e...@news.sonic.net...
> Clive George writes:
>
>>> 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.
>
>> 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.
> 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
Chalo
Matt O'Toole wrote:
>
> > 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
Peter Cole
the ultimate in old quill stems was nitto, imo. beautiful cold forging
> of the very highest quality.
>
I thought so too until mine broke. It is the only stem I've ever had
break...
Helmut Springer
> 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
ddog
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
ddog
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
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.
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.
> 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.
> 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
ddog
You should do a commercial for them doing a jump or something.
I'm 240-250 and 6', so a more compact load. Lots of variables in
construction variables
and riding components/forces. I've dealt with materials in
manufacturing, job shops, and foundry's so I'm pretty comfortable with
different material specs. I have to admit, there's a lot of shabby
components, like the single nut AL seat post clamps and threadless
stems; so if you don't research for several hours at least on web, I
could see where you had failures. China material grades are crap, so
that's another wild card right there.
Tried 6 different seats before I found SpiderFlex crotchless saddle. I
couldn't ride without it. But with it, constant spinning and no
problems.
I can see where you would rather not take chances and get the best
possible you can get. Post a link of you and your bike. I would be very
interested to see the combo. You sound like a professional football
player. I can't believe my Raleigh Supercourse rides so smooth with me
on it. I just feel sorry for your bike, lol. I used to engineer
man/machine interfaces in manufacturing. I'd always get the smallest
person and the biggest person to test my systems and make sure my
ranges were covered. That's why I'd like to see your setup and how you
are handling weight. Of course when I go to Walmart Groceries, I have a
hundred pounds on my Army duffle bag on my back. I'm planning to get a
front rack for additional reinforcment there, and when get new wheels,
will get the Phil Woods touring hubs.
Thanks,
Phil Bailey
Tim McNamara
jim beam <spamv...@bad.example.net> wrote:
> b...@mambo.ucolick.org wrote:
> > Paul Hobson wrote:
> >
> >> 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.
Although I don't see any obvious polishing of any part of the edges,
which I'd expect to see if the crack had been there a while. OTOH it
seems like it'd take a really bit hit to just snap it off in on shot.
> > 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.
It sure looks like the extension was just barely attached.
> cheap cheesy garbage. i don't have any welded stems.
I share your opinion. I don't have any welded aluminum stems for this
very reason. I've had one welded aluminum stem that started to crack
(3ttt as I recall), and I have had some Salsa and a couple of
Ritchey/Nitto welded steel stems that never showed any signs of failure.
Tim McNamara
Peter Cole <peter...@comcast.net> wrote:
How'd it break? And which Nitto model?
Mike Jacoubowsky
>>> 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.
Nope, happened before I became camera-crazy. Which means sometime before
1998, I'm thinking. The stem was very similar in appearance to a 3TTT model
at the time.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
"jim beam" <spamv...@bad.example.net> wrote in message
news:uuydnffvoIQThQDY...@speakeasy.net...
Andrew Lee
> 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?
>
> know of.
>
Do you remember this thread?
Michael Press
<1167916965.1...@i15g2000cwa.googlegroups.com>
,
"Qui si parla Campagnolo" <pe...@vecchios.com> 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 sh*t 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?
>
> Ritchey Comp or Salsa steel one.
Copy says the face plate is Al.
What about the single bolt steering tube clamp?
<http://xoomgear.com/manufacturer/Salsa/stems//Salsa_S_U_L_/368/>
--
Michael Press
Matt O'Toole
The problem with stems isn't ultimate strength, but fatigue.
Downhillers do not put anywhere near the number of fatigue cycles on stems
that road riders do. What downhill MTB accumulates tens of thousands of
miles?
Matt O.
Peter Cole
"Technomic". It broke right in the middle of the vertical part. These
are tall stems, but I didn't have it anywhere near maximum extension.
It was a benign break, other than being out a $40 stem, in that the
binder bolt held things together, much like a QR will hold a broken axle.
jim beam
other way around. downhillers experience much greater stress and are
therefore subject to much more fatigue. the cycles may have a lower
count, but with a higher stress, that is to be expected. check out an
s-n graph.
Mark Hickey
>Matt O'Toole wrote:
I'm betting (and think I recall reading) that this simply isn't true.
The ultimate stress on a stem isn't simply a matter of the size of the
bump. On a downhill racing bike, when the front wheel slams into a
three inch rock, the fat, low-pressure tire absorbs a great deal of
the impact, and any remaining impact that reaches the stem has to be
transmitted through a VERY cushy fork (one that probably has 5-6
inches of travel). The result is that the stem is loaded for a longer
period (as the tire and fork "soak up the bump"), but at a lower
magnitude.
OTOH, when a road bike hits a 1/2" rock, the 100psi (or more) tire can
only absorb so much of the impact, and the fork doesn't help a bit (at
least in a vertical sense - flexing fore/aft does help extend the
period). The period of the impact's effects is much shorter, but also
or a much greater amplitude.
Think of it this way - imagine trying to drive a nail using a bicycle
stem on an upside-down bicycle as the contact point with the nail, and
hammering on the front tire. You'd certainly have to work to get the
road bike's nail driven, but you'd never, ever get the nail driven
using the downhill bike as a buffer.
Mark "don't try that at home, kids" Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame
jobst....@stanfordalumni.org
Hey! That's my model for Brinelled head bearings. Its that (chip
seal) road impact on the tire that indents bearing balls into their
races.
Jobst Brandt
jim beam
the flights of imaginative fantasy people spew on this group to justify
their prejudice is sometimes quite amazing! there /is/ a reason
downhill bikes are made of strong fatigue resistant componentry you know....
Mark Hickey
>Mark Hickey writes:
>> Think of it this way - imagine trying to drive a nail using a
>> bicycle stem on an upside-down bicycle as the contact point with the
>> nail, and hammering on the front tire. You'd certainly have to work
>> to get the road bike's nail driven, but you'd never, ever get the
>> nail driven using the downhill bike as a buffer.
>
>Hey! That's my model for Brinelled head bearings. Its that (chip
>seal) road impact on the tire that indents bearing balls into their
>races.
Next time I'll put an attribution... ;-)
Thing is, I wish you hadn't commented... now Jim Beam is going to feel
obligated to explain how "it can't be so if Jobst agrees"... sigh.
Mark Hickey
jim beam
and i say so. but he keeps lecturing on materials applications and
theory and getting it badly wrong. now, you may not have areas of
expertise where intrusion of misinformation is a problem, but in
technical applications, it is.
jobst....@stanfordalumni.org
What did he say tangentially???
Jobst Brandt