Torque wrench question

PJay said:

Certain tools (BB tool, cassette lockring tool) require a variety of
adapters/sockets to fit them to the wrench. For example the BB tool fits
in a fairly long socket I have. Does extending the tool part away from the
wrench affect torque or should it be just as accurate?

Doesn't affect the torque. Torque is force times lever arm.

Quoted message said:

Regarding the BB, the general advice seems to be 'do it up nice and
tight', which I have done. There's no play when grabbing the cranks and
trying to move the BB, and I've ridden the bike reasonably hard with no
sign of movement or creaking from the BB area so I'm assuming that things
are fine. Are there any symptoms of too loose or too tight a BB I should
be looking out for?

By the time the crank gets loose, damage may have already occurred. It's
more common for a crank bolt to be under torqued than over torqued.

If you don't have a torque wrench, you can at least approximate the torque
by knowing the distance of from where you're applying the force (lever arm)
and approximating how many pounds of force you're applying (e.g., 10 lbs of
force and a 6" lever arm equals 5 ft-lbs).

Here are some common torque values for bikes:

http://www.faqs.org/faqs/bicycles-faq/part2/section-33.html

Art Harris

PJay said:

I'm still a bit unsure of myself around maintenance issues so I've been
using a torque wrench for a lot of bolts (hopefully one day I'll develop a
good feel for things without a torque wrench).

Torque to failure and then back off a quarter turn. Works for me.

Jasper

PJay said:

Certain tools (BB tool, cassette lockring tool) require a variety of
adapters/sockets to fit them to the wrench. For example the BB tool fits in
a fairly long socket I have. Does extending the tool part away from the
wrench affect torque or should it be just as accurate?

Torque is torque, which is just force times moment arm. Theoretically the
elasticity of the steel in the extending bits matters (especially on the
narrow bits), since part of the torque will be used to twist the tools
slightly, but I rather suspect that no bike part is going to be doing that
to any *significant* degree.

Jasper

PJay said:

I'm still a bit unsure of myself around maintenance issues so I've been
using a torque wrench for a lot of bolts (hopefully one day I'll develop a
good feel for things without a torque wrench).

People that work on other things, like cars, don't wish to develop a
'feel', why should you?

Quoted message said:

Certain tools (BB tool, cassette lockring tool) require a variety of
adapters/sockets to fit them to the wrench. For example the BB tool fits in
a fairly long socket I have. Does extending the tool part away from the
wrench affect torque or should it be just as accurate?

Regarding the BB, the general advice seems to be 'do it up nice and tight',
which I have done. There's no play when grabbing the cranks and trying to
move the BB, and I've ridden the bike reasonably hard with no sign of
movement or creaking from the BB area so I'm assuming that things are fine.
Are there any symptoms of too loose or too tight a BB I should be looking
out for?

Depends on the BB type. If it is a cup and ball BB, nice and tight'=it
is being killed as you ride it. For cart bearing type, tight is right.
If the crank is loose, via the BB spindle on a cart BB, something is
wrong.

Quoted message said:

Cheers,
PJay

Jasper Janssen said:

Torque is torque, which is just force times moment arm. Theoretically the
elasticity of the steel in the extending bits matters (especially on the
narrow bits), since part of the torque will be used to twist the tools
slightly, but I rather suspect that no bike part is going to be doing that
to any *significant* degree.

A socket (or an extension) twisting will not diminish
the torque at the bolt being tightened.

If you put a piece of foam rubber on top of your bathroom
scale before you stand on it, the scale's reading of your
weight won't be reduced. It's not like some of your weight is
used up by the foam and isn't also bearing down on the scale.

Tom Ace

Jasper Janssen said:

Torque is torque, which is just force times moment arm. Theoretically the
elasticity of the steel in the extending bits matters (especially on the
narrow bits), since part of the torque will be used to twist the tools
slightly, but I rather suspect that no bike part is going to be doing that
to any *significant* degree.

Incorrect. No matter the amount of twist, the torque is not reduced.
The twisting merely raises the energy requirement (torque times
angle).

Joe

PJay said:

Certain tools (BB tool, cassette lockring tool) require a variety of
adapters/sockets to fit them to the wrench. For example the BB tool fits in
a fairly long socket I have. Does extending the tool part away from the
wrench affect torque or should it be just as accurate?

It will be just as accurate.

--

David L. Johnson

__o | A mathematician is a machine for turning coffee into theorems.
_`\(,_ | -- Paul Erdos
(_)/ (_) |

Jasper Janssen said:

PJay said:

I'm still a bit unsure of myself around maintenance issues so I've been
using a torque wrench for a lot of bolts (hopefully one day I'll develop a
good feel for things without a torque wrench).

Torque to failure and then back off a quarter turn. Works for me.

But if the part failed, you sort of have to replace something, don't you?

--

David L. Johnson

__o | Deserves death! I daresay he does. Many that live deserve
_`\(,_ | death. And some that die deserve life. Can you give it to
(_)/ (_) | them? Then do not be too eager to deal out death in judgement.
-- J. R. R. Tolkein

David L. Johnson said:

Jasper Janssen said:

PJay said:

I'm still a bit unsure of myself around maintenance issues so I've been
using a torque wrench for a lot of bolts (hopefully one day I'll develop a
good feel for things without a torque wrench).

Torque to failure and then back off a quarter turn. Works for me.

But if the part failed, you sort of have to replace something, don't you?

Sort of.

Jasper

Qui si parla Campagnolo said:

PJay said:

I'm still a bit unsure of myself around maintenance issues so I've been
using a torque wrench for a lot of bolts (hopefully one day I'll develop a
good feel for things without a torque wrench).

People that work on other things, like cars, don't wish to develop a
'feel', why should you?

Cars are a whole lot more finicky about many things than bikes are, as in
the room between not tight enough and a snapped bolt is fairly narrow.
Bikes, not so much. Also, snapped bolts are much less of a problem as
well.

The high end of weight weenie and carbon-everything, Record this and Dura
Ace that, may be a bit of an exception, but even there you're not likely
to take anyone else with you when you crash -- unlike a Ford Explorer
ploughing into someone's home.

Jasper

"Qui si parla Campagnolo" wrote: People that work on other things, like
cars, don't wish to develop a 'feel', why should you?
^^^^^^^^^^^^^^^^^
Even skilled mechanics don't use a torque wrench on every fastener. The
"feel" for the proper tightness of a fastener is a rudimentary part of
mechanical skill.

The tire shops use a torque wrench to check the tightness of lug nuts, but I
don't even carry one in my car--do you?

On Sun, 30 Oct 2005 18:18:55 GMT, Jasper Janssen <[email hidden]>

Quoted message said:

Cars are a whole lot more finicky about many things than bikes are, as in
the room between not tight enough and a snapped bolt is fairly narrow.

After real tight comes real loose !

No I don't suppose I need to develop a 'feel' but it does seem that mention
of torque wrenches results in lot of comments about how you don't need them
and about developing a 'feel' for tightness.

I use torque wrenches because I have next to no skill or experience around
bike maintenance (although I'm keen to learn) and playing around with doing
up bolts without a torque wrench and guessing torque before checking things
with a torque wrench shows just how wildly inaccurate I am! Equally if you
have lots of experience and work on bikes regularly I'm sure that you can
develop a good feel for things but if like me your new to it and only
intend, for example, to whip the BB out every 6 months or so I guess it's
going to be tougher to do. Also a book on maintenance however good it is (I
have Zinn and the art of MTB maintenance) can't check things over for you
and say whether you've done things right or wrong.

I'm lacking confidence in my abilities and I guess that a torque wrench
makes things feel a little safer. I suppose this might mean developing an
over-reliance on the wrenches rather than developing a feel for things but I
suppose we've all got to start somewhere.

"Qui si parla Campagnolo" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

PJay said:

I'm still a bit unsure of myself around maintenance issues so I've been
using a torque wrench for a lot of bolts (hopefully one day I'll develop
a
good feel for things without a torque wrench).

People that work on other things, like cars, don't wish to develop a
'feel', why should you?

Quoted message said:

Certain tools (BB tool, cassette lockring tool) require a variety of
adapters/sockets to fit them to the wrench. For example the BB tool fits
in
a fairly long socket I have. Does extending the tool part away from the
wrench affect torque or should it be just as accurate?

Regarding the BB, the general advice seems to be 'do it up nice and
tight',
which I have done. There's no play when grabbing the cranks and trying to
move the BB, and I've ridden the bike reasonably hard with no sign of
movement or creaking from the BB area so I'm assuming that things are
fine.
Are there any symptoms of too loose or too tight a BB I should be looking
out for?

Depends on the BB type. If it is a cup and ball BB, nice and tight'=it
is being killed as you ride it. For cart bearing type, tight is right.
If the crank is loose, via the BB spindle on a cart BB, something is
wrong.

Quoted message said:

Cheers,
PJay

Leo Lichtman said:

The tire shops use a torque wrench to check the tightness of lug
nuts, but I don't even carry one in my car--do you?

Do they do that to make sure you can't possibly loosen them with a
normal lug wrench?

--
Ray "cross wrench in the trunk" Heindl
(remove the Xs to reply)

On Sun, 30 Oct 2005 21:23:41 GMT, Ray Heindl <[email hidden]>

Quoted message said:

Leo Lichtman said:

The tire shops use a torque wrench to check the tightness of lug
nuts, but I don't even carry one in my car--do you?

Do they do that to make sure you can't possibly loosen them with a
normal lug wrench?

No, they use the air gun on them to ensure that.

Nowadays with alloy wheels, they can't get away with that all the time
though. Alloys typically can only be torqued fairly loosely before they
break and they need to be fairly close to that point before the nuts stop
spinning off after a few miles.

Jasper

Leo Lichtman said:

"Qui si parla Campagnolo" wrote: People that work on other things, like
cars, don't wish to develop a 'feel', why should you?
^^^^^^^^^^^^^^^^^
Even skilled mechanics don't use a torque wrench on every fastener. The
"feel" for the proper tightness of a fastener is a rudimentary part of
mechanical skill.

The tire shops use a torque wrench to check the tightness of lug nuts, but I
don't even carry one in my car--do you?

If I had a flat, after putting on the spare, I would go to where I
bought the tires and have them repair/replace and then torque the
bolts. To not warp the disc which can be expensive. I don't continue to
drive for days or even hours.

I'm a bike mechanic, not a car mechanic but every decent, non-car
dealer' wrench I have ever talked to uses a torque wrench on things
like drive train bolts and head bolts. IT is NOT a rudimentary part of
mechanical skill. It is the lazy mechanic that doesn't take the few
extra seconds to use a torque wrnch instead of just a 'wrench'. The
difference between a good mechanic and a great one.

"Qui si parla Campagnolo" wrote: (clip) every decent, non-car dealer'
wrench I have ever talked to uses a torque wrench on things like drive train
bolts and head bolts. IT is NOT a rudimentary part of mechanical skill.
(clip)
^^^^^^^^^^^^^^^^^
Please read what I said. I did NOT say that good mechanics NEVER use torque
wrenches. Critical applications like head bolts, bearing cap bolts, etc
need to be torqued to spec. However, if any mechanic insisted on torquing
all the bolts on every job, he would be so slow he'd be out on his ear.
People who work with tools develop a "feel" for tightening torque.

Please tell me what kind of torque wrench you carry on your bike, since you
say you need it to make roadside repairs reliably.

Qui si parla Campagnolo said:

Leo Lichtman wrote:

Quoted message said:

Quoted message said:

Even skilled mechanics don't use a torque wrench on every fastener. The

^^^^^

Quoted message said:

Quoted message said:

"feel" for the proper tightness of a fastener is a rudimentary part of
mechanical skill.

Quoted message said:

If I had a flat, after putting on the spare, I would go to where I
bought the tires and have them repair/replace and then torque the
bolts. To not warp the disc which can be expensive. I don't continue to
drive for days or even hours.

Which disc can be warped by too loose lugnuts? The one the lugs are on?
I've never heard of that being an issue. Something I have heard about is
alloy rims cracking from too highly torqued lugnuts and, respectively,
alloys falling off because the tyre shop didn't dare put it on hard
enough.

The fullsize spare on my parent's car is a steel rim, though, rather than
an alloy, so that's not an issue, and because it's fullsize you can keep
driving it as long as you want, modulo that the spare will probably be
underinflated when you put it on, since it's highly inaccessible during
normal use, that it'll be unworn whereas the rest of the tyres might be a
bit worn by then (why did it puncture, after all), which can unbalance
things a bit, and that you don't have a spare *left*, which is a bit
problematic (but since the odds of puncturing car tyres are close to zero
these days, not that much of one).

Most spares these days are smaller than the rest of your wheels, which
means your front or rear diff, if it's on one of the drive wheels, will
constantly be 'turning a corner' and wearing way too fast. Which is why
they come with fairly severe speed and distance limits.

Quoted message said:

I'm a bike mechanic, not a car mechanic but every decent, non-car
dealer' wrench I have ever talked to uses a torque wrench on things
like drive train bolts and head bolts. IT is NOT a rudimentary part of

Sure, there are lots of fasteners, especially on cars, where torque is
critical. It's becoming more so for bikes, especially with clamping carbon
bits and all that jazz. Most fasteners on bikes, especially the
low-zoot-factor ones, though? Not so much. It's not that many decades ago
that a typical car could be worked in in your backyard with basic farmyard
tools and not a torque wrench in sight.

Quoted message said:

mechanical skill. It is the lazy mechanic that doesn't take the few
extra seconds to use a torque wrnch instead of just a 'wrench'. The
difference between a good mechanic and a great one.

I think the difference between a good mechanic and a great one is knowing
when you *don't* need the torque wrench.

Jasper

Qui si parla Campagnolo said:

I'm a bike mechanic, not a car mechanic but every decent, non-car
dealer' wrench I have ever talked to uses a torque wrench on things
like drive train bolts and head bolts. IT is NOT a rudimentary part of
mechanical skill. It is the lazy mechanic that doesn't take the few
extra seconds to use a torque wrnch instead of just a 'wrench'. The
difference between a good mechanic and a great one.

I think I'll aspire to mere goodness. It sounds less hoity-toity.

-Vee