How important is it to apply the correct torque?

On 10/03/2007 18:27, Duncan Smith said,

Quoted message said:

So, really how important is it? If I were to just ignore the torque
settings and tighten the bolts as normal - that'd be kind of all-right
wouldn't it?

I wonder how many people here have been cycling for decades and
maintaining their bikes for all that time, and have never used a torque
wrench?

I've certainly never had anything fall off yet.

--
Paul Boyd
http://www.paul-boyd.co.uk/

Duncan Smith said:

The instructions for fitting a front disc brake are very specific
about how much torque to apply; 5Nm here, 6.2Nm there, etc. In the
interests of self-sufficiency I'd ideally like to avoid the LBS, but a
torque-wrench from Wiggle is about £90 which I don't fancy forking out
for.

£90 is silly. I was sure there must be something more sensible.

Wiggle sell Park Torque Wrenches for about £30-odd, in two versions. The
smaller is 0-7Nm (60 inch pounds). The larger 0-70Nm (600 inch pounds). To
do up the bolts you describe above, you need the smaller one, you'd find it
hard to judge the difference between 5 and 6Nm (let alone 6.2!) on a
"pointer" wrench reading to 70Nm.

Quoted message said:

So, really how important is it? If I were to just ignore the torque
settings and tighten the bolts as normal - that'd be kind of all-right
wouldn't it?

Depends on your view of "safe", and if you have a feel for "about right" for
that type of fixing.

I'd be happy to do all bike things by hand feel, though I don't have a bike
with disk brakes.
On cars and motorcycles, I use a torque wrench for anything safety critical.

Quoted message said:

There's similar instructions when fitting cleats that can be ignored
without too much bother (although I did have one snap once that may
have been over-tightened..)

Illustating one potential issue of over-tightening. Not too much of an issue
on a cleat. Could be more serious on a disk brake.

- Nigel

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

in message <[email hidden]>, Paul Boyd

(') said:

On 10/03/2007 18:27, Duncan Smith said,

Quoted message said:

So, really how important is it? If I were to just ignore the torque
settings and tighten the bolts as normal - that'd be kind of all-right
wouldn't it?

I wonder how many people here have been cycling for decades and
maintaining their bikes for all that time, and have never used a torque
wrench?

Me.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

((DoctorWho)ChristopherEccleston).act();
uk.co.bbc.TypecastException: actor does not want to be typecast.
[adapted from autofile on /., 31/03/05]

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

Quoted message said:

The instructions for fitting a front disc brake are very specific
about how much torque to apply; 5Nm here, 6.2Nm there, etc. In the
interests of self-sufficiency I'd ideally like to avoid the LBS, but a
torque-wrench from Wiggle is about £90 which I don't fancy forking out
for.

So, really how important is it? If I were to just ignore the torque
settings and tighten the bolts as normal - that'd be kind of all-right
wouldn't it?

I'd say it can be done by hand, so long as you've got an idea of how tight
these things mean. If you undertighten, the bolts may come out - so check
after a bit of riding and tighten properly if necessary. If you overtighten,
your choice is basically one of strip the head, threads, or snap the screw -
if you've an idea how much a screw can take, you'll be fine.

But remember those numbers are really quite small - so don't stick it on a
long bar.

cheers,
clive

Duncan Smith said:

The instructions for fitting a front disc brake are very specific
about how much torque to apply; 5Nm here, 6.2Nm there, etc. In the
interests of self-sufficiency I'd ideally like to avoid the LBS, but a
torque-wrench from Wiggle is about £90 which I don't fancy forking out
for.

Get one from Sheldon http://sheldonbrown.com/tork-grip.html

--
Don Whybrow

Sequi Bonum Non Time

"To communicate with Mars, converse with spirits, To report the
behaviour of the sea monster, Describe the horoscope,
haruspicate or scry, Observe disease in signatures." (T.S.Eliot)

Mark said:

Hi

Duncan Smith said:

The instructions for fitting a front disc brake are very specific
about how much torque to apply; 5Nm here, 6.2Nm there, etc. In the
interests of self-sufficiency I'd ideally like to avoid the LBS, but
a torque-wrench from Wiggle is about £90 which I don't fancy forking
out for.

Yikes. Both of my torque wrenches together would cost less than that.
I expect Halfords sell them from £25 or so (haven't looked at one in a
while).

They do. Others sell them for even less (Screwfix is about £12.50).
However, its necessary to check the range they work over. Typical car
wrenches are for much higher figures than 5Nm, so you'll never set them
accurately to 5Nm and might as well use hand-feel.

- Nigel

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

Paul Boyd said:

On 10/03/2007 18:27, Duncan Smith said,

Quoted message said:

So, really how important is it? If I were to just ignore the torque
settings and tighten the bolts as normal - that'd be kind of all-right
wouldn't it?

I wonder how many people here have been cycling for decades and
maintaining their bikes for all that time, and have never used a torque
wrench?

I've certainly never had anything fall off yet.

I had lights, gear selector and something else fall off.
Today I had to tighten a bolt on a recently fitted mud guard.
I had a derailer cage fall apart a couple of weeks (light usage) after
stripping it down.

One the other hand I often overtighten stuff. I have snapped a bolt
holding a caliper brake together, and stripped a thread installing
handle bars on a new bike.

Last year I bought a 8-60Nm wrench from a well known toy shop, which I
use for larger bolts on the bike, it can also help give a feeling for
torques.
Alternatively hang a weight on a piece of string tied to an allen key.

Martin.

Duncan Smith said:

So, really how important is it? If I were to just ignore the torque
settings and tighten the bolts as normal - that'd be kind of all-right
wouldn't it?

Yes, 'kind off', but maybe not good enough for a safety critical
component?
Also, from the designer's viewpoint, you:
- design something with a bolted joint
- calculate what clamping load you want
- specify a bolt size / grade / torque to achieve that clamping load
(with a large margin of error)
- you'd really it to work like that in real life, so you put the
torque in the assembly instructions (and for good measure you put a
locking compound on the bolt so it will be unlikely to work loose)
How much did the disc brake etc. cost? Wouldn't you rather be
confident of it working as the designer/manufacturer intented?

Duncan Smith said:

The instructions for fitting a front disc brake are very specific
about how much torque to apply; 5Nm here, 6.2Nm there, etc. In the
interests of self-sufficiency I'd ideally like to avoid the LBS, but a
torque-wrench from Wiggle is about £90 which I don't fancy forking out
for.

So, really how important is it? If I were to just ignore the torque
settings and tighten the bolts as normal - that'd be kind of all-right
wouldn't it?

There's similar instructions when fitting cleats that can be ignored
without too much bother (although I did have one snap once that may
have been over-tightened..)

Many thanks,

Duncan.

I'm a torque wrench nazi but even so with disc bolts i usually go by good
and tight by hand with an torx key, more important is to make sure you
have some thread lock on them.
--
Three wheels good, two wheels ok

www.catrike.co.uk

Simon Brooke said:

in message <[email hidden]>, Paul Boyd

(') said:

On 10/03/2007 18:27, Duncan Smith said,

Quoted message said:

Quoted message said:

So, really how important is it? If I were to just ignore the torque
settings and tighten the bolts as normal - that'd be kind of all-right
wouldn't it?

Quoted message said:

I wonder how many people here have been cycling for decades and
maintaining their bikes for all that time, and have never used a torque
wrench?

Me.

--
[email hidden] (Simon Brooke)http://www.jasmine.org.uk/~simon/

((DoctorWho)ChristopherEccleston).act();
uk.co.bbc.TypecastException: actor does not want to be typecast.
[adapted from autofile on /., 31/03/05]

<aol> Me too! </aol>

....until I started working with carbon stuff, in particular clamping
carbon bars into stems. I've seem two sets of bars fail around the
stem clamp area, and when the stem face plate was removed, it appeared
as though the clamp had been overtightened - small cracks in the
lacquer on the bars, under and around the clamp area.

Now they may all be like that, or the cracks may have happened after
the bar had failed, or, or, or...

...but just in case, I now use a torque wrench on these bits, and also
on any "fancy" bits I happen across, e.g. titanium bolt sets. Maybe
it's just fear of the voodoo on my part, but I think that I'm familiar
enough with how tight to go on steel or aluminium, I just like the
extra security in materials that I'm less familiar with.

As an aside, I feel that I would have been overtightening small
fasteners by a considerable margin beyond the figure given in
installation instructions (the clicks seem to start at a lower "force"
on the wrench than I would have expected them to). I reckon I was
close enough on large fasteners (pedals -> crank, crank bolts etc.).

regards,

bookieb

Quoting Paul Boyd <[email hidden]>:

Quoted message said:

I wonder how many people here have been cycling for decades and
maintaining their bikes for all that time, and have never used a torque
wrench?

Crank installation is the thing I like a torque wrench for - jolly tight
but not too tight is awkward.
--
David Damerell <[email hidden]> Distortion Field!
Today is Saturday, March - a weekend.

Martin Dann <[email hidden]> whizzed past me shouting

Quoted message said:

I had lights, gear selector and something else fall off.
Today I had to tighten a bolt on a recently fitted mud guard.
I had a derailer cage fall apart a couple of weeks (light usage) after
stripping it down.

Go to your local hardware shop, tool dealer or Halfrauds and ask for a
tube of thread fixative. Also buy Nylock nuts in 4mm and 5mm sizes.
Nylock nuts turn stiffly so they won't vibrate off. No cyclist of sense
uses any other for lamps, mudguards and the like.

Where you've got to use Shimano's own nut, squeeze a little threadfix
onto the screw thread before you put the nut on: it has the same effect
but ONLY ONCE, so you need to reapply it after stripping down.

--
Sue ]🙁🙂

Why aren't we demandng regular retests for motorists?
Lots of them would obviously fail and that'd solve the congestion problem too.

Sue White wrote on 18/03/2007 09:59 +0100:

Quoted message said:

Martin Dann <[email hidden]> whizzed past me shouting

Quoted message said:

I had lights, gear selector and something else fall off.
Today I had to tighten a bolt on a recently fitted mud guard.
I had a derailer cage fall apart a couple of weeks (light usage) after
stripping it down.

Go to your local hardware shop, tool dealer or Halfrauds and ask for a
tube of thread fixative. Also buy Nylock nuts in 4mm and 5mm sizes.
Nylock nuts turn stiffly so they won't vibrate off. No cyclist of sense
uses any other for lamps, mudguards and the like.

Where you've got to use Shimano's own nut, squeeze a little threadfix
onto the screw thread before you put the nut on: it has the same effect
but ONLY ONCE, so you need to reapply it after stripping down.

Just make sure you get the right one. Some, such as Studlock, are
designed to make a permanent fixing and you will need to heat everything
up if you ever want to undo the fixing. Threadlock and Nutlock are
intended to allow disassembly.

--
Tony

"...has many omissions and contains much that is apocryphal, or at least
wildly inaccurate..."
Douglas Adams; The Hitchhiker's Guide to the Galaxy

Tony Raven <[email hidden]> whizzed past me shouting

Quoted message said:

Sue White wrote on 18/03/2007 09:59 +0100:

Quoted message said:

Martin Dann <[email hidden]> whizzed past me shouting

Quoted message said:

I had lights, gear selector and something else fall off.
Today I had to tighten a bolt on a recently fitted mud guard.
I had a derailer cage fall apart a couple of weeks (light usage)
after stripping it down.

Go to your local hardware shop, tool dealer or Halfrauds and ask for
a tube of thread fixative. Also buy Nylock nuts in 4mm and 5mm sizes.
Nylock nuts turn stiffly so they won't vibrate off. No cyclist of
sense uses any other for lamps, mudguards and the like.
Where you've got to use Shimano's own nut, squeeze a little
threadfix onto the screw thread before you put the nut on: it has the
same effect but ONLY ONCE, so you need to reapply it after stripping

Just make sure you get the right one. Some, such as Studlock, are
designed to make a permanent fixing and you will need to heat
everything up if you ever want to undo the fixing. Threadlock and
Nutlock are intended to allow disassembly.

A reliable shop wouldn't sell you that instead of the normal sort, but
Halfords might. And blokes never read the instructions...

--
Sue ];(🙂

Why aren't we demandng regular retests for motorists?
It'd probably work better than hanging or castrating them
and certainly be cheaper than life imprisonment.

Sue White wrote on 18/03/2007 22:11 +0100:

Quoted message said:

A reliable shop wouldn't sell you that instead of the normal sort, but
Halfords might. And blokes never read the instructions...

That is a sexist slur. We will read the instructions if everything else
has failed ;-)

--
Tony

"...has many omissions and contains much that is apocryphal, or at least
wildly inaccurate..."
Douglas Adams; The Hitchhiker's Guide to the Galaxy

Sue White said:

Tony Raven <[email hidden]> whizzed past me shouting

Quoted message said:

Sue White wrote on 18/03/2007 09:59 +0100:

Quoted message said:

Martin Dann <[email hidden]> whizzed past me shouting
>
> I had lights, gear selector and something else fall off.
> Today I had to tighten a bolt on a recently fitted mud guard.
> I had a derailer cage fall apart a couple of weeks (light usage)
>after stripping it down.
>
Go to your local hardware shop, tool dealer or Halfrauds and ask for
a tube of thread fixative. Also buy Nylock nuts in 4mm and 5mm sizes.
Nylock nuts turn stiffly so they won't vibrate off. No cyclist of
sense uses any other for lamps, mudguards and the like.
Where you've got to use Shimano's own nut, squeeze a little
threadfix onto the screw thread before you put the nut on: it has the
same effect but ONLY ONCE, so you need to reapply it after stripping

Quoted message said:

Quoted message said:

Just make sure you get the right one. Some, such as Studlock, are
designed to make a permanent fixing and you will need to heat
everything up if you ever want to undo the fixing. Threadlock and
Nutlock are intended to allow disassembly.

Quoted message said:

A reliable shop wouldn't sell you that instead of the normal sort, but
Halfords might. And blokes never read the instructions...

In an emergency a drop of kiwifruit juice works as a spanner
strippable nut lock.

--
Chris Malcolm [email hidden] DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Tony Raven said:

Sue White wrote on 18/03/2007 22:11 +0100:

Quoted message said:

A reliable shop wouldn't sell you that instead of the normal sort, but
Halfords might. And blokes never read the instructions...

That is a sexist slur. We will read the instructions if everything else
has failed ;-)

A few years ago I had a problem with a computer that I had owned for
well for a year. I got the instruction manuals out and found them still
shrink wrapped.

Martin.

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

Tony Raven said:

Sue White wrote on 18/03/2007 22:11 +0100:

Quoted message said:

A reliable shop wouldn't sell you that instead of the normal sort, but
Halfords might. And blokes never read the instructions...

That is a sexist slur. We will read the instructions if everything else
has failed ;-)

A few years ago I had a problem with a computer that I had owned for
well for a year. I got the instruction manuals out and found them still
shrink wrapped.

Martin.

Computers are not as complicated as bikes.
--
Cheers
the.Mark

in message <[email hidden]>, the.Mark

(') said:

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

Tony Raven said:

Sue White wrote on 18/03/2007 22:11 +0100:
>
> A reliable shop wouldn't sell you that instead of the normal sort,
> but
> Halfords might. And blokes never read the instructions...
>

That is a sexist slur. We will read the instructions if everything
else has failed ;-)

A few years ago I had a problem with a computer that I had owned for
well for a year. I got the instruction manuals out and found them still
shrink wrapped.

Martin.

Computers are not as complicated as bikes.

The average desktop computer these days has more working parts than all the
aircraft that had been produced anywhere in the world before 1945
(probably before 1970) put together. I'm pretty much prepared to bet that
my desktop computer (of the order of 100,000,000,000 working parts) has
more working parts than all the bicycles ever built put together.

Computers are quite complicated. Users, however...

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
Iraq war: it's time for regime change...
... go now, Tony, while you can still go with dignity.
[update three years after this .sig was written: it's still relevant]