Torque

I've recently acquired a flashy carbon-framed bike (realising as a
result that I'm basically a lugged-steel-last-for-ever person, but too
late now).

One notable thing about it is that several of its fitments specify
torques on them. I have a torque wrench but I really need one that can
manage less torque and has 1/4in drive so I can easily fit hex keys to
it.

So the question is: how much do these matter? In particular my
intuition is that for a traditional frame there was a big margin
between "a bit too tight" and "damage the frame / strip threads" while
for a carbon frame things might be a lot more fussy. But that's really
based on some notion that carbon is brittle compared to steel (which I
guess it probably is) rather than the perhaps more correct idea that
"writing torques on things makes them look more high-end".

(The reason this matters is that some of these are adjustments
(handlebars etc) that I tend do make on the first few rides, so I want
to know if I should lug a torque wrench around with me for a bit, or if
I can just use my old multitool thingy and do it all up a little too
tight to be safe: better than handlebars moving while on the bike!)

Thanks

--tim

On Jan 30, 4:29*am, Tim Bradshaw wrote:
I've recently acquired a flashy carbon-framed bike (realising as a
result that I'm basically a lugged-steel-last-for-ever person, but too
late now).

One notable thing about it is that several of its fitments specify
torques on them. *I have a torque wrench but I really need one that can
manage less torque and has 1/4in drive so I can easily fit hex keys to
it.

So the question is: how much do these matter? *In particular my
intuition is that for a traditional frame there was a big margin
between "a bit too tight" and "damage the frame / strip threads" while
for a carbon frame things might be a lot more fussy. *But that's really
based on some notion that carbon is brittle compared to steel (which I
guess it probably is) rather than the perhaps more correct idea that
"writing torques on things makes them look more high-end".

(The reason this matters is that some of these are adjustments
(handlebars etc) that I tend do make on the first few rides, so I want
to know if I should lug a torque wrench around with me for a bit, or if
I can just use my old multitool thingy and do it all up a little too
tight to be safe: better than handlebars moving while on the bike!)


While you might get away with "a little too tight" on alloy
components, carbon stuff is indeed different and "altt" can be a very
bad thing. Carbon is incredibly strong and surprisingly durable but
fares relatively poorly when involved in clamped interfaces.

On things like handlebars, also consider using specific "carbon
assembly paste." It's a grease-like paste containing a fine abrasive
like fumed silica in it to provide some "tooth" to minimize undesired
movement without having to resort to excessive clamping force. Some
folks have suggested that toothpaste also works as a readily available
substitute for the real stuff.

You may also want to experiment a bit with your torque wrench at home
to develop a feel for the rated torques so that you can make
adjustments on the road with simpler tools.

But for carbon, "too tight" is, in fact, too tight.

DR

lotta posts in RBT on this....try optimizing english language
searching in RBT and online..its magic....
'your manufacturer' has the specs...email or call....

we also hear rumors of LBS crunching parts using a torque wrench....

search 'TORQUE LUBRICATION EFFECTS'

IF NEW to this area, get a board, nuts, bolts, drill, insert and
torque by hand then measure with wrench....try balsa ? fiberglass from
the boat yard...

after yawl get a grip opn it, yawl find an ability to not snap
anything off...just feels that way

locktite is a biggie here as with lock, snug is enough.

On 30 jan, 12:29, Tim Bradshaw wrote:
I've recently acquired a flashy carbon-framed bike (realising as a
result that I'm basically a lugged-steel-last-for-ever person, but too
late now).

One notable thing about it is that several of its fitments specify
torques on them. *I have a torque wrench but I really need one that can
manage less torque and has 1/4in drive so I can easily fit hex keys to
it.

So the question is: how much do these matter? *In particular my
intuition is that for a traditional frame there was a big margin
between "a bit too tight" and "damage the frame / strip threads" while
for a carbon frame things might be a lot more fussy. *But that's really
based on some notion that carbon is brittle compared to steel (which I
guess it probably is) rather than the perhaps more correct idea that
"writing torques on things makes them look more high-end".

(The reason this matters is that some of these are adjustments
(handlebars etc) that I tend do make on the first few rides, so I want
to know if I should lug a torque wrench around with me for a bit, or if
I can just use my old multitool thingy and do it all up a little too
tight to be safe: better than handlebars moving while on the bike!)

Thanks

--tim

Test setup.
Remember what you want to change.
Make change at home.
Test new setup next ride.

Or
Use carbon paste.
Change set up on your ride and tighten the bolts very conservative.
There is a margin between tightened very conservative and moving the
bars while riding when you avoid rough terrain.
At home tighten the bolts further with the specd torque.

Or
Take you torque wrench with you.

Never torque a bit too high.

Lou

On 1/30/2012 6:29 AM, Tim Bradshaw wrote:
I've recently acquired a flashy carbon-framed bike (realising as a
result that I'm basically a lugged-steel-last-for-ever person, but too
late now).

One notable thing about it is that several of its fitments specify
torques on them. I have a torque wrench but I really need one that can
manage less torque and has 1/4in drive so I can easily fit hex keys to it.

So the question is: how much do these matter? In particular my intuition
is that for a traditional frame there was a big margin between "a bit
too tight" and "damage the frame / strip threads" while for a carbon
frame things might be a lot more fussy. But that's really based on some
notion that carbon is brittle compared to steel (which I guess it
probably is) rather than the perhaps more correct idea that "writing
torques on things makes them look more high-end".

(The reason this matters is that some of these are adjustments
(handlebars etc) that I tend do make on the first few rides, so I want
to know if I should lug a torque wrench around with me for a bit, or if
I can just use my old multitool thingy and do it all up a little too
tight to be safe: better than handlebars moving while on the bike!)


I'm with DR. I would probably hand tighten a bottle cage or maybe a
brake mount but that's about it. I would say that any place that specs
a torque, you should use it. Carbon frames are probably not as brittle
as I'm afraid they are (never known someone who cracked one) but they
are certainly expensive enough to take care.

On 2012-01-30 16:27:39 +0000, Duane Hebert said:

I'm with DR. I would probably hand tighten a bottle cage or maybe a
brake mount but that's about it. I would say that any place that specs
a torque, you should use it. Carbon frames are probably not as brittle
as I'm afraid they are (never known someone who cracked one) but they
are certainly expensive enough to take care.

Thanks (& thanks to the other people who responded). I'll carry it
with me for a while (it's not huge since it's a 1/4in-drive one for the
things I might want to fiddle with, and experience tells me that the
"remember to adjust when I get home" thing means I forget to do it). I
have the same fear about brittleness, and the same intuition that it's
probably not rational, but why take risks with an expensive thing as
you say.

Tim Bradshaw wrote:
I've recently acquired a flashy carbon-framed bike (realising as a
result that I'm basically a lugged-steel-last-for-ever person, but too
late now).

One notable thing about it is that several of its fitments specify
torques on them. I have a torque wrench but I really need one that can
manage less torque and has 1/4in drive so I can easily fit hex keys to it.

Sounds to me like you just came up with justification for buying a new
tool. That in itself isn't a bad thing.

On steel and aluminum, it took me many years, starting as a kid, to
correctly judge "tight enough" vs. "too tight." Having developed that
judgment, I don't use a torque wrench except on really critical fasteners.

If I were to do something as unlikely as buy a carbon frame, there's no
way I'd trust my judgment, at least at first. I'd buy the tool and use it.


--
- Frank Krygowski

Frank Krygowski wrote:

Sounds to me like you just came up with justification for buying a new
tool. That in itself isn't a bad thing.

Well, I wanted to get a 1/2 to 1/4 in adaptor, but could only find 1/2 to
3/8 and 3/8 to 1/4 locally, and stacking them was just getting too much (I
know, order one on intarweb, but I feel better if I'm making some effort to
keep the last decent tool shop near me in business).

Tim Bradshaw wrote:
Frank Krygowski wrote:

Sounds to me like you just came up with justification for buying a new
tool. That in itself isn't a bad thing.

Well, I wanted to get a 1/2 to 1/4 in adaptor, but could only find 1/2 to
3/8 and 3/8 to 1/4 locally, and stacking them was just getting too much (I
know, order one on intarweb, but I feel better if I'm making some effort to
keep the last decent tool shop near me in business).


Snap On doesn't seem to offer one.

Your 1/2" torque wrench can resolve small increments for
carbon bicycle frame fastener values? Mine can't. For
example, modern carbon frame seat post binder values are
typically 4 to 6nm, hard to see on a 0-10-20-30 scale.

Tools typically used for that application, such as the
Mariposa, are scaled 0~15nm by 1nm increments.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

http://www.summitracing.com/search/P...=torque+wrench

exp with no wrench/wrench per Holtman...stronger you are, higher
torques are accurately possible or correct physical pulling position
with helper bar increases accuracy

with jug holders....and loctite only a seated bolt is
necessary...surely toy can seat a bolt after examing the seat for
flatness off course ! and bolt threads....and with lubing loctite.

the bars and uppper stem are no boig deal again per H.....find when
the works moves ubder your common pressure...somewhat loose is ok for
the eventual .8 crash