Maintenance Manuals

Hobbes@spnb&s.com said:

jim beam said:

Frank Drackman said:

"jim beam" <[email hidden]> wrote in message
news:[email hidden]...
> Ryan Cousineau wrote:
>> In article <[email hidden]>,
>> BigJulie <[email hidden]> wrote:
>>
>>> sutherland's
>>>
>>> http://www.amazon.com/Sutherlands-Handbook-bicycle-mechanics-Sutherland/dp/091
>>> 4578065/ref=pd_bbs_2/102-4791940-4852967?ie=UTF8&s=books&qid=1191039436&sr=8-2
>>>
>>>
>>> On Sep 29, 12:05 am, Mark <[email hidden]> wrote:
>>>> Well as I am increasingly intrigued by the mechanics of bikes. There
>>>> is a lot I just have never taken apart, put back together, and frankly
>>>> don't fully understand how things work. I wondered if there is a book
>>>> that is accepted as "the book to have on bike maintenance" that shows
>>>> pictures and step by step instructions much the way the Chiltons book
>>>> does for auto repair.
>>>>
>>>> I'd also be interested in books on bike design. Now I would like to
>>>> keep the theory to a practical level. No I have no idea to turn this
>>>> into an engineering project. I am already married to an engineer and
>>>> the last thing one needs is two engineers in the same house. lol
>> At a much lower price, Zinn and the Art of Mountain Bike Maintenance (and
>> the similar Road Bike Maintenance) are good Chilton-level books. I'd just
>> get the one for your primary kind of ride, as much of the material
>> overlaps, and the differences aren't liable to catch you out unless
>> you're a roadie and you decide to start doing your own fork maintenance
>> on your MTB.
>>
>> Sheldonbrown.com seems like it has directions on virtually every
>> mechanical repair known to cycling, so it's almost as good as having your
>> own bike manual.
>>
>> I make no submission on most bike design books, but regular contributor
>> here Jobst Brandt literally wrote the book
> /a/ book.
>
>> on bicycle wheels, called "The Bicycle Wheel," and it covers both the
>> theory of wheels and the proper procedure for wheelbuilding.
>>
> procedure, yes. theory? some of it is badly awry. spoke tension "as
> high as the rim can bear" for example is based on a fundamental
> misunderstanding by the author and that is of the most practical [and
> costly] consequence to the novice builder - excess tension can cause a
> higher propensity for rim buckling and directly cause rim cracking. the
> book should should be amended to specify spoke tension "as determined by
> the rim manufacturer".
I guess that we all saw that coming...sad

what's sad? having to correct gross error? or being gullible so that
having smoke blown up your skirt seems like it's a good thing?

This is NOT torquing a bolt until it starts to strip and then backing off a
little. Stop pretending it is. The phrase "as high as the rim can bear" does NOT
equal "higher than the rim can bear."

you don't understand the problem. because the rim doesn't pretzel
doesn't mean it's not at its strength limit. pretzel means yield. but
fatigue loading for aluminum is typically 1/3 yield. if spoke tension
is close to the limit of gross yield, it surely shouldn't be too hard to
understand that point loading is also beyond that necessary to ensure a
decent fatigue life - particularly in highly anisotropic materials like
rim extrusions where strength is much lower perpendicular to the
extrusion axis.

Quoted message said:

Using the specified tension from the
manufacturer is a convenient, well documented determination of how high a
tension the rim can bear. Not a bad thing. Not necessarily in conflict with the
other.

If you want to keep beating this horse please continue in private, there's
nothing but bones and maggots left and it smells bad. Stop.

ignorance is no excuse. i want the facts corrected so that people stop
wasting their money by prematurely destroying their rims with excess
spoke tension. what do /you/ want? other than to not be confronted
with uncomfortable reality that's you've been misled of course.

Quoted message said:

Peter Cole said:

Frank Drackman said:

"jim beam" <[email hidden]> wrote in message
news:[email hidden]...
> Ryan Cousineau wrote:
>> In article <[email hidden]>,
>> BigJulie <[email hidden]> wrote:
>>
>>> sutherland's
>>>
>>> http://www.amazon.com/Sutherlands-Handbook-bicycle-mechanics-Sutherland/dp/091
>>> 4578065/ref=pd_bbs_2/102-4791940-4852967?ie=UTF8&s=books&qid=1191039436&sr=8-2
>>>
>>>
>>> On Sep 29, 12:05 am, Mark <[email hidden]> wrote:
>>>> Well as I am increasingly intrigued by the mechanics of bikes. There
>>>> is a lot I just have never taken apart, put back together, and frankly
>>>> don't fully understand how things work. I wondered if there is a book
>>>> that is accepted as "the book to have on bike maintenance" that shows
>>>> pictures and step by step instructions much the way the Chiltons book
>>>> does for auto repair.
>>>>
>>>> I'd also be interested in books on bike design. Now I would like to
>>>> keep the theory to a practical level. No I have no idea to turn this
>>>> into an engineering project. I am already married to an engineer and
>>>> the last thing one needs is two engineers in the same house. lol
>> At a much lower price, Zinn and the Art of Mountain Bike Maintenance (and
>> the similar Road Bike Maintenance) are good Chilton-level books. I'd just
>> get the one for your primary kind of ride, as much of the material
>> overlaps, and the differences aren't liable to catch you out unless
>> you're a roadie and you decide to start doing your own fork maintenance
>> on your MTB.
>>
>> Sheldonbrown.com seems like it has directions on virtually every
>> mechanical repair known to cycling, so it's almost as good as having your
>> own bike manual.
>>
>> I make no submission on most bike design books, but regular contributor
>> here Jobst Brandt literally wrote the book
> /a/ book.
>
>> on bicycle wheels, called "The Bicycle Wheel," and it covers both the
>> theory of wheels and the proper procedure for wheelbuilding.
>>
> procedure, yes. theory? some of it is badly awry. spoke tension "as
> high as the rim can bear" for example is based on a fundamental
> misunderstanding by the author and that is of the most practical [and
> costly] consequence to the novice builder - excess tension can cause a
> higher propensity for rim buckling and directly cause rim cracking. the
> book should should be amended to specify spoke tension "as determined by
> the rim manufacturer".
I guess that we all saw that coming...sad

And completely wrong, it's not what the book says at all.

Dear Peter,

Here's what the 3rd edition says:

FINDING THE RIGHT TENSION

The following method works well in determining proper spoke tension
for conventional road rims of up to 43 0 grams with 36 spokes. Tighten
all the spokes a quarter turn at a time, starting at the valve stem
hole. Once a distinct tone can be made by plucking, and spokes are not
easily squeezed together by grasping them in pairs, it is time to
check tension. After each round of tightening, test the tension by
stress relieving. If the wheel becomes untrue in two large waves
during stress relieving, the maximum, safe tension has been exceeded.
Approach this tension carefully to avoid major rim distortions. When
the wheel loses alignment from stress relieving, loosen all spokes a
half turn before retruing the wheel

Cheers,

Carl Fogel

Yes, I know, I have that edition.

It also describes, in a previous section "Final Tensioning", use of a
tensiometer (with drawing), and comparison by tone to a known good wheel
as methods of achieving proper tension.

In the context, the method described above is given as an alternative
with the stated qualifications (<430g, 36 spokes), presumably for those
without tensiometers.

He goes on to say that for heavy rims or road rims with less than 32
spokes that tensioning is usually at the limit when nipples can no
longer be easily turned.

The overall impression I get is that Jobst is trying to give people a
feel for how tight spokes should be. It seems obvious that, for rims
where the manufacturer has specified a maximum spoke tension, those
limits should be observed, and a tensiometer is required to do that.

From its online manual, Mavic indicates that conventional 3 cross
wheels should have tensions in the 70-90kg range. They also set weight
limits on their road wheels (2008) for 100kg, bike rider & gear. Both
seem low. Perhaps wheel builders using Mavic product should read the
fine print carefully and never build without a tensiometer.

It would be interesting to know what the actual tension would be if the
quoted procedure was followed for the kind of rim described. As far as
I know, no one has reported that.

Peter Cole said:

Quoted message said:

Peter Cole said:

Frank Drackman wrote:
> "jim beam" <[email hidden]> wrote in message
> news:[email hidden]...
>> Ryan Cousineau wrote:
>>> In article <[email hidden]>,
>>> BigJulie <[email hidden]> wrote:
>>>
>>>> sutherland's
>>>>
>>>> http://www.amazon.com/Sutherlands-Handbook-bicycle-mechanics-Sutherland/dp/091
>>>>
>>>> 4578065/ref=pd_bbs_2/102-4791940-4852967?ie=UTF8&s=books&qid=1191039436&sr=8-2
>>>>
>>>>
>>>>
>>>> On Sep 29, 12:05 am, Mark <[email hidden]> wrote:
>>>>> Well as I am increasingly intrigued by the mechanics of bikes.
>>>>> There
>>>>> is a lot I just have never taken apart, put back together, and
>>>>> frankly
>>>>> don't fully understand how things work. I wondered if there is
>>>>> a book
>>>>> that is accepted as "the book to have on bike maintenance" that
>>>>> shows
>>>>> pictures and step by step instructions much the way the Chiltons
>>>>> book
>>>>> does for auto repair.
>>>>>
>>>>> I'd also be interested in books on bike design. Now I would
>>>>> like to
>>>>> keep the theory to a practical level. No I have no idea to turn
>>>>> this
>>>>> into an engineering project. I am already married to an
>>>>> engineer and
>>>>> the last thing one needs is two engineers in the same house. lol
>>> At a much lower price, Zinn and the Art of Mountain Bike
>>> Maintenance (and the similar Road Bike Maintenance) are good
>>> Chilton-level books. I'd just get the one for your primary kind of
>>> ride, as much of the material overlaps, and the differences aren't
>>> liable to catch you out unless you're a roadie and you decide to
>>> start doing your own fork maintenance on your MTB.
>>>
>>> Sheldonbrown.com seems like it has directions on virtually every
>>> mechanical repair known to cycling, so it's almost as good as
>>> having your own bike manual.
>>>
>>> I make no submission on most bike design books, but regular
>>> contributor here Jobst Brandt literally wrote the book
>> /a/ book.
>>
>>> on bicycle wheels, called "The Bicycle Wheel," and it covers both
>>> the theory of wheels and the proper procedure for wheelbuilding.
>>>
>> procedure, yes. theory? some of it is badly awry. spoke tension
>> "as high as the rim can bear" for example is based on a fundamental
>> misunderstanding by the author and that is of the most practical
>> [and costly] consequence to the novice builder - excess tension can
>> cause a higher propensity for rim buckling and directly cause rim
>> cracking. the book should should be amended to specify spoke
>> tension "as determined by the rim manufacturer".
> I guess that we all saw that coming...sad
And completely wrong, it's not what the book says at all.

Dear Peter,

Here's what the 3rd edition says:

FINDING THE RIGHT TENSION

The following method works well in determining proper spoke tension
for conventional road rims of up to 43 0 grams with 36 spokes. Tighten
all the spokes a quarter turn at a time, starting at the valve stem
hole. Once a distinct tone can be made by plucking, and spokes are not
easily squeezed together by grasping them in pairs, it is time to
check tension. After each round of tightening, test the tension by
stress relieving. If the wheel becomes untrue in two large waves
during stress relieving, the maximum, safe tension has been exceeded.
Approach this tension carefully to avoid major rim distortions. When
the wheel loses alignment from stress relieving, loosen all spokes a
half turn before retruing the wheel

Cheers,

Carl Fogel

Yes, I know, I have that edition.

It also describes, in a previous section "Final Tensioning", use of a
tensiometer (with drawing), and comparison by tone to a known good wheel
as methods of achieving proper tension.

In the context, the method described above is given as an alternative
with the stated qualifications (<430g, 36 spokes), presumably for those
without tensiometers.

He goes on to say that for heavy rims or road rims with less than 32
spokes that tensioning is usually at the limit when nipples can no
longer be easily turned.

The overall impression I get is that Jobst is trying to give people a
feel for how tight spokes should be. It seems obvious that, for rims
where the manufacturer has specified a maximum spoke tension, those
limits should be observed, and a tensiometer is required to do that.

From its online manual, Mavic indicates that conventional 3 cross
wheels should have tensions in the 70-90kg range. They also set weight
limits on their road wheels (2008) for 100kg, bike rider & gear. Both
seem low. Perhaps wheel builders using Mavic product should read the
fine print carefully and never build without a tensiometer.

It would be interesting to know what the actual tension would be if the
quoted procedure was followed for the kind of rim described. As far as
I know, no one has reported that.

to avoid pretzel? what's the point? longevity depends on avoiding rim
cracking and fatigue, and the manufacturer has reported that already.
increasing tension doesn't increase strength so there's no point seeking
more of it.

In article <[email hidden]>,

Qui si parla Campagnolo-www.vecchios.com said:

Ryan Cousineau said:

In article <[email hidden]>,
"Frank Drackman" <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Quoted message said:

I guess that we all saw that coming...sad

Actually, thanks to killfiles, I didn't see it at all.

--
Ryan Cousineau [email hidden]://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

Which killfile do you use> And is it applicable to Google groups?

Been here before...some authors beg for killfile.

My primary newsreader is the venerable MT-Newswatcher on the Mac. It has
an integrated killfile system which allows me to kill articles by
subject, author, with or without a time limit, and in a single group,
across all groups, or in just one branch of a hierarchy (eg I could kill
an author, but only in rec.bicycles.* groups, so I could still read
their sci.astronomy posts). It surely has more power than even that, but
I have not yet needed it.

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

jim beam said:

Peter Cole wrote:

Quoted message said:

Quoted message said:

It would be interesting to know what the actual tension would be if
the quoted procedure was followed for the kind of rim described. As
far as I know, no one has reported that.

to avoid pretzel? what's the point?

I'm not sure what you're trying to say. Jobst infers that following his
alternate procedure will result in a spoke tension of around 100kg.

Quoted message said:

longevity depends on avoiding rim
cracking and fatigue, and the manufacturer has reported that already.
increasing tension doesn't increase strength so there's no point seeking
more of it.

Mavic (and most others I presume) spec a min and max. I haven't seen
anyone (including Jobst) recommending using more than the max spec. So
what's the problem?

You seem to be sure that Jobst's alternate method will produce higher
than max spec spoke tensions. How do you know that?

I've used lots of wheels, Mavic & others, the only cracking I ever got
was with Mavic Reflex rims (2). I don't know what tension they were
built to, I don't think it was very high, they had to be Locktited. All
of my other rims just wore out on the brake track.

jim beam' aka evan williams said:

Ryan Cousineau said:

...
I make no submission on most bike design books, but regular
contributor here Jobst Brandt literally wrote the book

/a/ book.

Quoted message said:

on bicycle wheels, called "The Bicycle Wheel," and it covers both the
theory of wheels and the proper procedure for wheelbuilding.

procedure, yes. theory? some of it is badly awry. spoke tension "as
high as the rim can bear" for example is based on a fundamental
misunderstanding by the author and that is of the most practical [and
costly] consequence to the novice builder - excess tension can cause a
higher propensity for rim buckling and directly cause rim cracking. the
book should should be amended to specify spoke tension "as determined by
the rim manufacturer".

I wonder if "jim" has a macro for anti-Jobst replies?

--
Tom Sherman - Holstein-Friesland Bovinia
A Real Cyclist [TM] keeps at least one bicycle in the bedroom.

--
Posted via a free Usenet account from http://www.teranews.com

Tom 'Johnny Sunset' Sherman said:

jim beam' aka evan williams said:

Ryan Cousineau said:

...
I make no submission on most bike design books, but regular
contributor here Jobst Brandt literally wrote the book

/a/ book.

Quoted message said:

on bicycle wheels, called "The Bicycle Wheel," and it covers both the
theory of wheels and the proper procedure for wheelbuilding.

procedure, yes. theory? some of it is badly awry. spoke tension "as
high as the rim can bear" for example is based on a fundamental
misunderstanding by the author and that is of the most practical [and
costly] consequence to the novice builder - excess tension can cause a
higher propensity for rim buckling and directly cause rim cracking.
the book should should be amended to specify spoke tension "as
determined by the rim manufacturer".

I wonder if "jim" has a macro for anti-Jobst replies?

that's "corrective", not "anti-jobst".

Peter Cole said:

jim beam said:

Peter Cole wrote:

Quoted message said:

Quoted message said:

It would be interesting to know what the actual tension would be if
the quoted procedure was followed for the kind of rim described. As
far as I know, no one has reported that.

to avoid pretzel? what's the point?

I'm not sure what you're trying to say. Jobst infers that following his
alternate procedure will result in a spoke tension of around 100kg.

"infers"??? how can you infer a number??? oh, wait, it's /convenient/
to state it after the fact! my mistake.

Quoted message said:

Quoted message said:

longevity depends on avoiding rim cracking and fatigue, and the
manufacturer has reported that already. increasing tension doesn't
increase strength so there's no point seeking more of it.

Mavic (and most others I presume) spec a min and max. I haven't seen
anyone (including Jobst) recommending using more than the max spec. So
what's the problem?

what is numerical about "as high as the rim can bear"??? modern deep
profile rims can take much more stress before they buckle, but the alloy
from which they are made is just as anisotropic and very similar in
yield. a rim stiff enough to take double spoke tension [as determined
by the jobstian method] before buckling isn't going to make rims last
very long when it comes to cracking. use of a tensiometer is therefore
essential.

Quoted message said:

You seem to be sure that Jobst's alternate method will produce higher
than max spec spoke tensions. How do you know that?

because i've tried it!

Quoted message said:

I've used lots of wheels, Mavic & others, the only cracking I ever got
was with Mavic Reflex rims (2). I don't know what tension they were
built to,

er,...

Quoted message said:

I don't think it was very high,

that's a cop-out - for someone purporting to be an engineer, it's also
remarkably incurious.

Quoted message said:

they had to be Locktited.

eh? aren't you one of those that condemns loctite?

Quoted message said:

All
of my other rims just wore out on the brake track.

as will happen to all rims if accident or excess spoke tension doesn't
kill them first.

On Sep 30, 11:23 pm, jim beam <[email hidden]> wrote:

Peter Cole wrote:

snip

Quoted message said:

Quoted message said:

You seem to be sure that Jobst's alternate method will produce
higher than max spec spoke tensions. How do you know that?

Quoted message said:

because i've tried it!

Specifically, which 36 hole, conventional cross-section rim of 430 or
less grams did you try this on and what is your source for the
manufacturer's recommended spoke tension range? I'm asking because
I've learned from previous threads to not believe anything you say.
The exclamation point you put after your statement doesn't lift it
above the normal credibility level of zero.

Quoted message said:

modern deep profile rims can take much more stress before they > buckle.... a rim stiff enough to take double spoke tension [as > determined by the jobstian method] before buckling isn't going to > make rims last very long when it comes to cracking. use of a > tensiometer is therefore essential.

Everyone would be aware of this either from their own knowledge,
experience and common sense or from having read Jobst's book. Nothing
like stating the obvious as if it's an original and profound
revelation from the sage of RBT, jim - never in doubt, often in error
- beam.

--

Spike

Quoted message said:

On Sep 30, 11:23 pm, jim beam <[email hidden]> wrote:

Peter Cole wrote:

snip

Quoted message said:

Quoted message said:

You seem to be sure that Jobst's alternate method will produce
higher than max spec spoke tensions. How do you know that?

Quoted message said:

because i've tried it!

Specifically, which 36 hole, conventional cross-section rim of 430 or
less grams did you try this on and what is your source for the
manufacturer's recommended spoke tension range? I'm asking because
I've learned from previous threads to not believe anything you say.
The exclamation point you put after your statement doesn't lift it
above the normal credibility level of zero.

Quoted message said:

modern deep profile rims can take much more stress before they > buckle.... a rim stiff enough to take double spoke tension [as > determined by the jobstian method] before buckling isn't going to > make rims last very long when it comes to cracking. use of a > tensiometer is therefore essential.

Everyone would be aware of this either from their own knowledge,
experience and common sense or from having read Jobst's book. Nothing
like stating the obvious as if it's an original and profound
revelation from the sage of RBT, jim - never in doubt, often in error
- beam.

Dear Spike,

Sorry, but people aren't actually reading "The Bicycle Wheel," which
is probably why they don't quote it.

The book does _say_ to use a tensiometer to determine the correct
tension, but only in the sense of measuring an already established
correct tension for later use in building the next identical wheel.

The book says that the correct tension is _first_ determined by other
methods, namely raising tension on 36-spoke count wheels until
squeezing spoke pairs together produces a deformed wheel or when the
spokes on low-count or deep-section wheels can no longer be tightened
without excessive windup:

"The final tension of a wheel built by feel is affected by the mood of
its builder. By using a tension measuring tool a builder can establish
proper tension, then repeat it. Such a tool, a tensiometer, measures
the deflection of a spoke over a given span in response to a standard
load. The dial is calibrated in tension or displacement. Either
measure is equally useful for wheel building. It is not necessary to
know the actual tension but only that the tension has reached the
desired mark. The correct maximum tension for a specific wheel design
must still be determined first by stress relieving. For some deep
section rims or wheels with few spokes, the limit of tension is
reached when spokes can no longer be tightened further without
excessive windup. For subsequent wheels of the same type the
tensiometer can accurately and quickly determine whether spokes have
reached the predetermined tension."

--3rd edition

Obviously, deep-section 36-spoke rims can stand more tension before
distorting than MA-2's.

I'm not arguing about wheel-building methods, just pointing out that
people who want to claim that Jobst's book says something ought to
provide quotes to back up their claims.

As far as I can see, Jim Beam's description is closer to being
accurate--the book says to raise tension until the rim fails to stay
in shape if you squeeze the spoke pairs, or to tighten low-count
spokes until the spoke wind-up reaches some undefined "excessive"
point.

If anyone has suggestions about other passages, I'll be glad to search
my scanned 3rd edition or browse through the first two editions. None
of them have an index (indexing was expensive back then), so I
sympathize with text-scholars who vaguely remember whatever edition
they have saying _something_ and are having trouble finding it.

(The deep section/low count/spoke windup comments were added in the
3rd edition. The book was re-written almost sentence by sentence,
twice, so don't be surprised if you have trouble finding things.
Remember, the first edition was based on and referred to 5, 6, and 7
speed rear wheels--things changed rapidly between 1981 and 1993.)

The only example of specific tension in the 3rd edition is this: "If
its spokes are tensioned to 1000 N, a 36-spoke wheel will support
approximately 400 kg."

The 1,000 Newtons mentioned is just an example for an ensuing
discussion of when spokes might go slack, not a specific tension
recommendation. It's the equivalent of 102 kgf, and a common figure
for many wheels today.

In any case, Jobst expects that to be reduced by 30% through the
constriction of the inflated tire:

"Although spoke tension is the principal static load on the rim,
tubular tire inflation has a similar effect. When inflated, the tire
becomes fatter and shrinks in circumference. The resulting force
depends on the tire cross section, cord angle and inflation pressure.
A tubular racing tire, inflated to 0.86 MPa, for instance, shrinks
with a force of 300 N (see Equation 8 in Part III). Its effect on
spoke tension can be detected with a tensiometer."

--3rd edition

That reduces the _effective_ spoke tension from about 100 kgf to about
70 kgf. Dianne's measurements suggest about a reduction of about 15
kgf for 700c box-section clinchers.

On a less pedantic note, the "kgf" commonly used nowadays for spoke
tension does not appear in the 3rd edition of 1993, just the two cited
passages with "kg".

It's possible that tensiometers were so rare back in 1981-1993 that no
manufacturers gave recommended kgf (or kg or newton or pound) tensions
for their rims, and that Jobst was simply giving the best possible
advice for the era when you had to find the right tension yourself.
Only after tensiometers became widely available would manufacturers
start giving the recommendations that can still be darned hard to find
today.

If so (and it's just a theory that tension recommendations were scarce
or non-existent), then Jobst was simply suggesting that using a
tensiometer to record whatever tension you found best by using other
methods was a quick and convenient way to build the next wheel.

Build the first wheel by raising tension until spoke-squeezing put it
out of true or the spokes began to wind up excessively (before anyone
sneers, try to define how much wind-up is excessive), measure the
results with a tensiometer (and also use it to check for even tension
all around the wheel), record the tension, and presto! The next wheel
is much quicker and easier to build because you just tighten it to the
X marked on your tensiometer.

Cheers,

Carl Fogel

Quoted message said:

On Sep 30, 11:23 pm, jim beam <[email hidden]> wrote:

Peter Cole wrote:

snip

Quoted message said:

Quoted message said:

You seem to be sure that Jobst's alternate method will produce
higher than max spec spoke tensions. How do you know that?

Quoted message said:

because i've tried it!

Specifically, which 36 hole, conventional cross-section rim of 430 or
less grams did you try this on

i've done this test on several wheels with different rims - mavic open
pro, x517, x618, etc. and of course, an ma2. spoke count and lacing
make no difference.

Quoted message said:

and what is your source for the
manufacturer's recommended spoke tension range?

i called mavic's tech department. 1-888-go-mavic. they're very helpful.

Quoted message said:

I'm asking because
I've learned from previous threads to not believe anything you say.

that's a personal issue for you spike. if i state something like
"modulus = stress/strain", you can independently verify "believability"
for yourself. and you could verify "believability" of the above too if
you had a tensiometer. and used it.

Quoted message said:

The exclamation point you put after your statement doesn't lift it
above the normal credibility level of zero.

that's a personal issue for you spike.

Quoted message said:

Quoted message said:

modern deep profile rims can take much more stress before they > buckle.... a rim stiff enough to take double spoke tension [as > determined by the jobstian method] before buckling isn't going to > make rims last very long when it comes to cracking. use of a > tensiometer is therefore essential.

Everyone would be aware of this either from their own knowledge,
experience and common sense or from having read Jobst's book. Nothing
like stating the obvious as if it's an original and profound
revelation from the sage of RBT, jim - never in doubt, often in error
- beam.

"obvious"? it's apparently not "obvious" to jobst since he doesn't
cover this in his book. kind of a serious omission since the excess
spoke tension his procedure causes is directly responsible for rim
destruction that costs consumers and manufacturers a small fortune.

Quoted message said:

Sorry, but people aren't actually reading "The Bicycle Wheel," which
is probably why they don't quote it.

The book does _say_ to use a tensiometer to determine the correct
tension, but only in the sense of measuring an already established
correct tension for later use in building the next identical wheel.

To me, this would presume no manufacturer's spec on max spoke tension.
Otherwise, if you had a max spec and a tensiometer, why exceed it?

Quoted message said:

The book says that the correct tension is _first_ determined by other
methods, namely raising tension on 36-spoke count wheels until
squeezing spoke pairs together produces a deformed wheel or when the
spokes on low-count or deep-section wheels can no longer be tightened
without excessive windup:

Quoted message said:

Obviously, deep-section 36-spoke rims can stand more tension before
distorting than MA-2's.

What this approach does is determine the maximum spoke tension by
finding the rim buckling point and then backing off considerably to
establish a safety margin.

The buckling point is determined by the rim cross section (thin column
buckling). The load that causes this buckling is circumferential
compression. It's not obvious to me that the wider, less tall cross
sections of older rims like the MA-2 buckled under less load than the
newer narrow/tall cross sections (Reflex, Open Pro). My guess is that
the MA-2 would be (a little) more buckle resistant, if anything.

Quoted message said:

I'm not arguing about wheel-building methods, just pointing out that
people who want to claim that Jobst's book says something ought to
provide quotes to back up their claims.

As far as I can see, Jim Beam's description is closer to being
accurate--the book says to raise tension until the rim fails to stay
in shape if you squeeze the spoke pairs, or to tighten low-count
spokes until the spoke wind-up reaches some undefined "excessive"
point.

There is nothing wrong with this method until the spoke tension exceeds
that which the spoke bed can take without cracking. Presumably, it is
that limit which is reflected in the manufacturer's maximum spoke
tension spec. -- for those who publish such things.

A quick look at online data seems to show Sun recommending 110kg max for
all road rims, and Mavic 70-90kg for "classic" rims. This would seem to
indicate Mavic rims have weaker spoke beds, at least in "classic" rims,
something many of us have observed directly. Other Mavic rims have max
tension spec up to 160kg.

My question was what is the actual tension achieved with Jobst's method
using rims that fit his criteria. He implies that will get you to around
100kg.

Quoted message said:

The only example of specific tension in the 3rd edition is this: "If
its spokes are tensioned to 1000 N, a 36-spoke wheel will support
approximately 400 kg."

Quoted message said:

The 1,000 Newtons mentioned is just an example for an ensuing
discussion of when spokes might go slack, not a specific tension
recommendation. It's the equivalent of 102 kgf, and a common figure
for many wheels today.

All the equations in the back of the book seem to take 100kg as nominal
spoke tension. I assumed that the "buckle point" method got him there
with the typical rims he referenced, otherwise I don't know why he'd use
it as a nominal number.

Quoted message said:

In any case, Jobst expects that to be reduced by 30% through the
constriction of the inflated tire:

Quoted message said:

(see Equation 8 in Part III). Its effect on
spoke tension can be detected with a tensiometer."

One of us is misunderstanding that equation. I interpret it to mean that
the circumferential force from tire inflation nets (compression minus
expansion) to ~400N. Immediately above in equation #7, he calculates the
compressive rim force from spoke tension at 5730N, roughly a 7% change
in spoke tension, assuming a purely linear effect.

I don't understand what this has to do with anything, though.

Quoted message said:

If so (and it's just a theory that tension recommendations were scarce
or non-existent), then Jobst was simply suggesting that using a
tensiometer to record whatever tension you found best by using other
methods was a quick and convenient way to build the next wheel.

That's what he said. If spoke breakage isn't a limit (as shown), then
the only limits to spoke tension are rim buckling and bed cracking.
Buckling can be experimentally determined easily with his method.

As for bed cracking, if Jobst's method gets you to 100kg for "classic"
rims, you're good for all Sun road rims (according to them), but a bit
high for Mavic. Since Mavic knows how to make rims that can take 160kg
or more, it seems like they made their "classics" a bit on the dainty
side. Perhaps they should have made that better known -- even a feature:
"Our rims require 20% less spoke tension!".

jim beam said:

Peter Cole wrote:

Quoted message said:

Quoted message said:

Mavic (and most others I presume) spec a min and max. I haven't seen
anyone (including Jobst) recommending using more than the max spec. So
what's the problem?

what is numerical about "as high as the rim can bear"??? modern deep
profile rims can take much more stress before they buckle, but the alloy
from which they are made is just as anisotropic and very similar in
yield. a rim stiff enough to take double spoke tension [as determined
by the jobstian method] before buckling isn't going to make rims last
very long when it comes to cracking. use of a tensiometer is therefore
essential.

Jobst excluded heavy and/or deep section and/or low spoke count rims
from his alternate method.

If you had a tensiometer, and a manufacturer's max spoke tension spec.,
it would seem obvious to anyone to use both. The obvious context of his
method is where a spec and perhaps even a tensiometer weren't available.

Quoted message said:

Quoted message said:

You seem to be sure that Jobst's alternate method will produce higher
than max spec spoke tensions. How do you know that?

because i've tried it!

I don't believe you've reported this before. What rim and what was your
final tension?

Quoted message said:

Quoted message said:

I've used lots of wheels, Mavic & others, the only cracking I ever got
was with Mavic Reflex rims (2). I don't know what tension they were
built to,

er,...

Quoted message said:

I don't think it was very high,

that's a cop-out - for someone purporting to be an engineer, it's also
remarkably incurious.

Quoted message said:

they had to be Locktited.

eh? aren't you one of those that condemns loctite?

I cite the Locktite as evidence they weren't too high. I didn't build
the wheel. It was my first bike purchase when I reentered cycling many
years ago. I only became curious after the fact when a wheel that had to
be Locktited to keep nipples from unscrewing also cracked spoke holes. I
started learning about wheels. That was my last wheel to use Locktite.
Also my last one to crack.

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

Quoted message said:

that's a personal issue for you spike. if i state something like "modulus
= stress/strain", you can independently verify "believability" for
yourself.

Just like you can verify "believability" of beamboy statements like
-"sikorski [sic] materials lecture more than 30 years ago" on non-existent
CF helo rotors
-cracking sound made by CF is used as damage indicator by aircraft
manufacturers
-he is a "former metallurgist"... er, make that "metallurgist"
-etc, etc, etc...

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

Quoted message said:

Tom 'Johnny Sunset' Sherman said:

I wonder if "jim" has a macro for anti-Jobst replies?

that's "corrective", not "anti-jobst".

That's "anti-Jobst", not "corrective".

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

Quoted message said:

Quoted message said:

Specifically, which 36 hole, conventional cross-section rim of 430 or
less grams did you try this on

i've done this test on several wheels with different rims - mavic open
pro, x517, x618, etc. and of course, an ma2. spoke count and lacing make
no difference.

Then you should be able to post pictures of these on your little flickr
website. At least 4 rims mentioned there.

Mark said:

Well as I am increasingly intrigued by the mechanics of bikes. There
is a lot I just have never taken apart, put back together, and frankly
don't fully understand how things work. I wondered if there is a book
that is accepted as "the book to have on bike maintenance" that shows
pictures and step by step instructions much the way the Chiltons book
does for auto repair.

I'd also be interested in books on bike design. Now I would like to
keep the theory to a practical level. No I have no idea to turn this
into an engineering project. I am already married to an engineer and
the last thing one needs is two engineers in the same house. lol

And there's Talbot's Designing and Building Your Own Frameset, but I
had no idea it was so expensive now. I'll have to move mine to the
safe!

http://www.amazon.com/Designing-Building-Your-Own-Frameset/dp/0960241833

Cheers,

Mark said:

I wondered if there is a book
that is accepted as "the book to have on bike maintenance" that shows
pictures and step by step instructions much the way the Chiltons book
does for auto repair.

Hi Mark,

I noticed that (before the thread shifted to a discussion on
wheelbuilding) no one mentioned the four-volume Barnett's manual. It
uses detailed step-by-step procedures. I've been very happy with it.

Regards,
Anthony

Quoted message said:

Quoted message said:

On Sep 30, 11:23 pm, jim beam <[email hidden]> wrote:

Quoted message said:

Peter Cole wrote:

Quoted message said:

snip

Quoted message said:

Quoted message said:

> You seem to be sure that Jobst's alternate method will produce
> higher than max spec spoke tensions. How do you know that?

Quoted message said:

Quoted message said:

because i've tried it!

Quoted message said:

Specifically, which 36 hole, conventional cross-section rim of 430 or
less grams did you try this on and what is your source for the
manufacturer's recommended spoke tension range? I'm asking because
I've learned from previous threads to not believe anything you say.
The exclamation point you put after your statement doesn't lift it
above the normal credibility level of zero.

Quoted message said:

Quoted message said:

modern deep profile rims can take much more stress before they > buckle.... a rim stiff enough to take double spoke tension [as > determined by the jobstian method] before buckling isn't going to > make rims last very long when it comes to cracking. use of a > tensiometer is therefore essential.

Quoted message said:

Everyone would be aware of this either from their own knowledge,
experience and common sense or from having read Jobst's book. Nothing
like stating the obvious as if it's an original and profound
revelation from the sage of RBT, jim - never in doubt, often in error
- beam.

Dear Spike,

Sorry, but people aren't actually reading "The Bicycle Wheel," which
is probably why they don't quote it.

The book does _say_ to use a tensiometer to determine the correct
tension, but only in the sense of measuring an already established
correct tension for later use in building the next identical wheel.

The book says that the correct tension is _first_ determined by other
methods, namely raising tension on 36-spoke count wheels until
squeezing spoke pairs together produces a deformed wheel or when the
spokes on low-count or deep-section wheels can no longer be tightened
without excessive windup:

"The final tension of a wheel built by feel is affected by the mood of
its builder. By using a tension measuring tool a builder can establish
proper tension, then repeat it. Such a tool, a tensiometer, measures
the deflection of a spoke over a given span in response to a standard
load. The dial is calibrated in tension or displacement. Either
measure is equally useful for wheel building. It is not necessary to
know the actual tension but only that the tension has reached the
desired mark. The correct maximum tension for a specific wheel design
must still be determined first by stress relieving. For some deep
section rims or wheels with few spokes, the limit of tension is
reached when spokes can no longer be tightened further without
excessive windup. For subsequent wheels of the same type the
tensiometer can accurately and quickly determine whether spokes have
reached the predetermined tension."

--3rd edition

Obviously, deep-section 36-spoke rims can stand more tension before
distorting than MA-2's.

I'm not arguing about wheel-building methods, just pointing out that
people who want to claim that Jobst's book says something ought to
provide quotes to back up their claims.

As far as I can see, Jim Beam's description is closer to being
accurate--the book says to raise tension until the rim fails to stay
in shape if you squeeze the spoke pairs, or to tighten low-count
spokes until the spoke wind-up reaches some undefined "excessive"
point.

If anyone has suggestions about other passages, I'll be glad to search
my scanned 3rd edition or browse through the first two editions. None
of them have an index (indexing was expensive back then), so I
sympathize with text-scholars who vaguely remember whatever edition
they have saying _something_ and are having trouble finding it.

(The deep section/low count/spoke windup comments were added in the
3rd edition. The book was re-written almost sentence by sentence,
twice, so don't be surprised if you have trouble finding things.
Remember, the first edition was based on and referred to 5, 6, and 7
speed rear wheels--things changed rapidly between 1981 and 1993.)

The only example of specific tension in the 3rd edition is this: "If
its spokes are tensioned to 1000 N, a 36-spoke wheel will support
approximately 400 kg."

The 1,000 Newtons mentioned is just an example for an ensuing
discussion of when spokes might go slack, not a specific tension
recommendation. It's the equivalent of 102 kgf, and a common figure
for many wheels today.

In any case, Jobst expects that to be reduced by 30% through the
constriction of the inflated tire:

"Although spoke tension is the principal static load on the rim,
tubular tire inflation has a similar effect. When inflated, the tire
becomes fatter and shrinks in circumference. The resulting force
depends on the tire cross section, cord angle and inflation pressure.
A tubular racing tire, inflated to 0.86 MPa, for instance, shrinks
with a force of 300 N (see Equation 8 in Part III). Its effect on
spoke tension can be detected with a tensiometer."

--3rd edition

That reduces the _effective_ spoke tension from about 100 kgf to about
70 kgf. Dianne's measurements suggest about a reduction of about 15
kgf for 700c box-section clinchers.

On a less pedantic note, the "kgf" commonly used nowadays for spoke
tension does not appear in the 3rd edition of 1993, just the two cited
passages with "kg".

It's possible that tensiometers were so rare back in 1981-1993 that no
manufacturers gave recommended kgf (or kg or newton or pound) tensions
for their rims, and that Jobst was simply giving the best possible
advice for the era when you had to find the right tension yourself.
Only after tensiometers became widely available would manufacturers
start giving the recommendations that can still be darned hard to find
today.

If so (and it's just a theory that tension recommendations were scarce
or non-existent), then Jobst was simply suggesting that using a
tensiometer to record whatever tension you found best by using other
methods was a quick and convenient way to build the next wheel.

Build the first wheel by raising tension until spoke-squeezing put it
out of true or the spokes began to wind up excessively (before anyone
sneers, try to define how much wind-up is excessive), measure the
results with a tensiometer (and also use it to check for even tension
all around the wheel), record the tension, and presto! The next wheel
is much quicker and easier to build because you just tighten it to the
X marked on your tensiometer.

Cheers,

Carl Fogel

Thank you for your response, Carl. I have quoted and responded to
some of it below.

Quoted message said:

Sorry, but people aren't actually reading "The Bicycle Wheel," which
is probably why they don't quote it.

In the case of jim beam, even if he did read Jobst Brandt's The
Bicycle Wheel, I think he would continue to misquote it.

Quoted message said:

The book does _say_ to use a tensiometer to determine the correct
tension, but only in the sense of measuring an already established
correct tension for later use in building the next identical wheel.
The book says that the correct tension is _first_ determined by other
methods, namely raising tension on 36-spoke count wheels until
squeezing spoke pairs together produces a deformed wheel or when the
spokes on low-count or deep-section wheels can no longer be tightened
without excessive windup:

Within the context of the whole book, put in the simplest terms, the
author recommends that a tensiometer be used to measure proper spoke
tension. In the Third Edition under the paragraph on page 104 titled
"Final Tensioning" he states, "Spoke tension can be directly measured
with a tensiometer...." Elsewhere, on page 118, in the paragraph
titled "Tensiometer" the author says, "By using a tension measuring
tool a builder can establish proper tension, then repeat it." Nowhere
does the author restrict how the tensiometer measured proper tension
is determined. The one method that he helpfully sets forth on page
105 is, he notes, for "...conventional road rims of up to 430 grams
with 36 spokes." For other wheel systems such as those with heavy
rims, with deep section rims, and those with fewer than 32 spokes, he
does not provide a method but does observe that tensioning may be at
its limit when nipples are not easily tightened. The author in no way
precludes determining proper spoke tension from rim manufactures
recommendations, from measurements of manufacturers' prebuilt wheels,
from a reliable wheelset that has already served long and hard, or by
other means.

It would be nice if there was a single, easy, and all encompassing
answer to the question: What's The Proper Tension? But, such an answer
is not possible; the situation does not allow for it. The author of
course knows this, and so doesn't provide such an answer. A few
readers, I imagine, are disappointed. Bizarrely, one individual
gives the author an answer and then says he is wrong.

--

Spike

jim beam said:

[email hidden] wrote:

Quoted message said:

Quoted message said:

I've learned from previous threads to not believe anything you say.

that's a personal issue for you spike.

Actually, it's not a personal issue; it's a personal observation. The
same observation made by many others who have read your posts.
--
Spike