Spoke Question (butted vs. straight gauge)

[Mike S.]

<[email protected]> wrote in message news:[email protected]...
> Mike Shaw writes:
>
> > I know from personal experience that 15/16 butted spokes make too flexy a wheel for me. Diving
> > into corners in a criterium is not the place for a flexy front wheel, no matter how durable or
> > comfortable the ride. Other people that I know swear by 15/16 spokes for all of their wheels.
>
> Now we are getting to the nature of your beliefs and that you have not seen the book that dissects
> all this in fine detail so that no stone should remain unturned, so to speak. You didn't say how
> many spokes you use on these "too flexy" wheels but from the implications, they are not 16 spoke
> wheels. Even if they were, you could not feel the elasticity of the spokes, these deflections
> being on the order of riding over a piece of copier bond paper, on the order of 0.004". Next time
> you ride over a sheet of paper and feel it, let me know about it.
>
Did YOU ride my wheels? Have you even SEEN my wheels? I built them, I rode them, and YES, they were
flexy. See, and you wonder why I question what engineers tell me. Tire pressure wasn't the issue, it
was 180# diving into corners and sprinting out of them that made them flex.

I agree that just riding along in a straight line, I'm not going to feel the spokes elongate.
Sprinting and cornering on the above-mentioned wheels is a completely different story.

> > I've seen what happens when shops build wheels for individuals that HAVE to have 28 hole wheels,
> > even though they weigh 200#+. I've seen or heard from friends what happens when a Spinergy
> > 4-spoke's blades separate from the hub in a sprint.
>
> Let's not grasp at straws and make overweight straw men who ride on faddish wheels. I think you
> are sliding way down the slippery slope, far from the original subject, that of not trusting
> engineers or what they write, regardless of how well reasoned and supported by experimental work.

>
> > I've built wheels for myself, friends, and customers that have had problems, and others that
> > have seldom seen another spoke wrench. Yes, I've used info from "the Book" as a basis for a lot
> > of what I've done, but even more, I've used experience to figure out what should work where.
>
> So why didn't you write the book. I only took up that cause because bicycle shops had no idea of
> the parameters that affect wheel failure, sudden and fatigue. In fact fatigue failure and fretting
> damage to bearings was and probably still is a mystery to many experienced bicycle mechanics.
>
> >>> So, while I'm not an anti-intellectualist, I reserve the right to think for myself. If what
> >>> the intellectualist flies in the face of personal observation, I'm going to go with what I've
> >>> actually seen, felt, experienced rather than believe everything blindly.
>
> >> The implication is that engineers are blind and lacking practical experience while mechanics
> >> are savant and perceptive.
>
> > Not at all. Some engineers certainly are blind and lacking practical experience, just as not all
> > mechanics are savants.
>
> So? Can you tell the difference? Recognizing a charlatan in contrast to a person who know what he
> knows and doesn't know is one of the things most people learn and master as adults. Raking a whole
> class of people, by race, color, or chosen profession (engineering) rings of jingoism. You don't
> happen to work for the White House do you?
>
> >>> So, that's my $0.02, next?
>
> >> You don't get any change for such a negative contribution. Go to school.
>
>
> > I did, where do you think I figured out that engineers don't know diddly about the real world.
> > When you have one as a roommate and he burns water 'cause he doesn't have the common sense God
> > gave an ant, ya gotta scratch your head.
>
> Keep it up. I think there is room in the US Foreign service for you.
>
> Jobst Brandt [email protected] Palo Alto CA

 

[Mark Hickey]

"Mike S." <mikeshaw2@coxDOTnet> wrote:

><[email protected]> wrote in message

>> Now we are getting to the nature of your beliefs and that you have not seen the book that
>> dissects all this in fine detail so that no stone should remain unturned, so to speak. You didn't
>> say how many spokes you use on these "too flexy" wheels but from the implications, they are not
>> 16 spoke wheels. Even if they were, you could not feel the elasticity of the spokes, these
>> deflections being on the order of riding over a piece of copier bond paper, on the order of
>> 0.004". Next time you ride over a sheet of paper and feel it, let me know about it.
>>
>Did YOU ride my wheels? Have you even SEEN my wheels? I built them, I rode them, and YES, they were
>flexy. See, and you wonder why I question what engineers tell me. Tire pressure wasn't the issue,
>it was 180# diving into corners and sprinting out of them that made them flex.
>
>I agree that just riding along in a straight line, I'm not going to feel the spokes elongate.
>Sprinting and cornering on the above-mentioned wheels is a completely different story.

Mike, you've just painted yourself into an inescapable corner. If you were strong enough to "stretch
the spokes in a sprint", you'd make Super Mario look like a double amputee. You may not agree with
blind trust in engineering, but you can test this if you don't believe it.

Stand your bike up with the right pedal at the three o'clock position, with you standing on the
pedals. Have someone carefully measure a pulling spoke. Now grab a hand full of rear brake and put
your full weight on the right pedal, pulling up as hard as you can on the left pedal. In this
scenario, you will be putting the absolute maximum torque on the drivetrain.

Have your "helper" read out the new, longer spoke length. Uh oh.

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame

 

[Tim McNamara]

In article <[email protected]>, "Mike S." <mikeshaw2@coxDOTnet> wrote:

> <[email protected]> wrote in message
> news:[email protected]...
> > Mike Shaw writes:
> >
> > > I know from personal experience that 15/16 butted spokes make too flexy a wheel for me. Diving
> > > into corners in a criterium is not the place for a flexy front wheel, no matter how durable or
> > > comfortable the ride. Other people that I know swear by
> > > 15/16 spokes for all of their wheels.
> >
> > Now we are getting to the nature of your beliefs and that you have not seen the book that
> > dissects all this in fine detail so that no stone should remain unturned, so to speak. You
> > didn't say how many spokes you use on these "too flexy" wheels but from the implications, they
> > are not 16 spoke wheels. Even if they were, you could not feel the elasticity of the spokes,
> > these deflections being on the order of riding over a piece of copier bond paper, on the order
> > of 0.004". Next time you ride over a sheet of paper and feel it, let me know about it.
> >
> Did YOU ride my wheels? Have you even SEEN my wheels? I built them, I rode them, and YES, they
> were flexy. See, and you wonder why I question what engineers tell me. Tire pressure wasn't the
> issue, it was 180# diving into corners and sprinting out of them that made them flex.

Perhaps you should wonder about the veracity of your perceptions rather than what engineers tell
you. HOW could you tell it was the wheels that were flexing? HOW did you isolate that from fork
flex, frame flex, tire deformation? Do you understand that your wheels see basically no side loading
in a corner, no matter how fast you are going, unless you keep the bike vertical while turning?

You built them, you say? The only way for pretensioned spoked wheels to be flexy (so that it's
noticeable- the top of your rear wheel flexes 1 to 2 mm to the left every time you mash down the
pedals while climbing, but no one notices this by feel) is if the spokes are massively
undertensioned.

Frankly, if your wheels flexed enough to be felt while cornering, the wheel was dangerously close to
collapse and would probably have gone all the way to failure.

> I agree that just riding along in a straight line, I'm not going to feel the spokes elongate.
> Sprinting and cornering on the above-mentioned wheels is a completely different story.

I'd guess you need to learn how to properly tension a wheel, from your description.

FWIW, I'm not an engineer. I've built hundreds of wheels in my days as a bike shop wrench and for
friends since I got a job that actually pays the bills. I raced for 10 years. I am 6'4" and weighed
about 195 lbs throughout my racing career. I never had a wheel flex noticeably. No one else I know
has ever complained about wheels flexing.

 

[Peter Cole]

"Qui si parla Campagnolo" <[email protected]> wrote in message
news:[email protected]...
>
> Would never try to 'deter' you Herr Jobst...

What's with that? We all know the image you're trying to conjure with that title. That's way
out of line.

 

[Peter Cole]

"Patrick Lamb" <[email protected]> wrote in message news:[email protected]...
> Kenny Lee wrote:
> > Say, didn't some bike dudes invent the airplane at a place named Kitty Hawk, North Carolina.
> > They weren't engineers were they?
>
> Are you kidding? Those guys probably wouldn't have known a partial differential equation if one
> bit them!

While formal engineering, especially aeronautical, didn't exist in their day, the Wright bros.
certainly weren't the rube tinkerers that popular culture makes them out to be, they couldn't have
been and still have solved the very difficult problems they did. To work out the problems of control
and stable flight, they had to have a beyond state-of-the-art understanding of the physics and
engineering involved.

from : http://wright.nasa.gov/overview.htm

Wright Brothers' Invention Process:

The process which lead to the first successful airplane is exactly the same process used by NASA
engineers today to solve problems.

(1899 - 1902) - Researched How Things Fly

The first step in any new program or project is research. The Wright Brothers first performed a
literature search to find out the state of aeronautical knowledge at their time. They wrote to the
Smithsonian and obtained technical papers regarding aerodynamics. They read about the works of
Cayley, and Langley, and the hang-gliding flights of Otto Lilienthal.

They corresponded with Octave Chanute concerning some of their ideas. They studied the problems
which had been encountered by previous flyers and they talked about possible solutions to the
problems. They looked for answers to the problems of flight by observing large gliding birds. They
decided that control of the flying aircraft would be the most crucial and hardest problem to solve
and they had some ideas for solving that problem.

 

[Sdb]

That's exactly what I'm talking about. People who have a busted wheel are going to take it to a
wheelbuilder to get fixed, right? And probably not the one that built it originally, (if
they're good consumers) right? So...the good wheelbuilder is going to see more busted wheels
than the bad one.

make sense now?

"Mike Latondresse" <[email protected]> wrote in message
news:[email protected]...
> Tim McNamara <[email protected]> wrote in news:[email protected]:
>
> >
> > The wheelbuilder, if he does things right, will not see a lot of failures.
>
> On the other hand if he gets a reputation as a good wheel builder he may see a lot of falures,
> just none of his own.

 

[Robin Hubert]

"Tim McNamara" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "Mike S." <mikeshaw2@coxDOTnet> wrote:
>
> > <[email protected]> wrote in message
> > news:[email protected]...
> > > Mike Shaw writes:
> > >
> > > > I know from personal experience that 15/16 butted spokes make too flexy a wheel for me.
> > > > Diving into corners in a criterium is not the place for a flexy front wheel, no matter how
> > > > durable or comfortable the ride. Other people that I know swear by
> > > > 15/16 spokes for all of their wheels.
> > >
> > > Now we are getting to the nature of your beliefs and that you have not seen the book that
> > > dissects all this in fine detail so that no stone should remain unturned, so to speak. You
> > > didn't say how many spokes you use on these "too flexy" wheels but from the implications, they
> > > are not 16 spoke wheels. Even if they were, you could not feel the elasticity of the spokes,
> > > these deflections being on the order of riding over a piece of copier bond paper, on the order
> > > of 0.004". Next time you ride over a sheet of paper and feel it, let me know about it.
> > >
> > Did YOU ride my wheels? Have you even SEEN my wheels? I built them, I rode them, and YES, they
> > were flexy. See, and you wonder why I question what engineers tell me. Tire pressure wasn't the
> > issue, it was 180# diving into corners and sprinting out of them that made them flex.
>
> Perhaps you should wonder about the veracity of your perceptions rather than what engineers tell
> you. HOW could you tell it was the wheels that were flexing? HOW did you isolate that from fork
> flex, frame flex, tire deformation? Do you understand that your wheels see basically no side
> loading in a corner, no matter how fast you are going, unless you keep the bike vertical while
> turning?
>
> You built them, you say? The only way for pretensioned spoked wheels to be flexy (so that it's
> noticeable- the top of your rear wheel flexes 1 to 2 mm to the left every time you mash down the
> pedals while climbing, but no one notices this by feel) is if the spokes are massively
> undertensioned.
>
> Frankly, if your wheels flexed enough to be felt while cornering, the wheel was dangerously close
> to collapse and would probably have gone all the way to failure.

Aw, c'mon Tim! You know he was feeling tire flex and pavement fluxutations, and imagining the rest.
His wheels might be ok. If he rides them like he says and they haven't collapsed, they're probably
ok, at least.

>
> > I agree that just riding along in a straight line, I'm not going to feel the spokes elongate.
> > Sprinting and cornering on the above-mentioned wheels is a completely different story.
>
> I'd guess you need to learn how to properly tension a wheel, from your description.
>
> FWIW, I'm not an engineer. I've built hundreds of wheels in my days as a bike shop wrench and for
> friends since I got a job that actually pays the bills. I raced for 10 years. I am 6'4" and
> weighed about 195 lbs throughout my racing career. I never had a wheel flex noticeably. No one
> else I know has ever complained about wheels flexing.

Robin Hubert

 

[Sdb]

"Tim McNamara" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "SDB" <[email protected]> wrote:
>
> > IMHO, the wheel builder/concrete pourer analogy is not a fair one. The wheel builder most likely
> > sees a lot of failures and learns from them (using statistics, someone without knowledge of
> > wheel mechanics can learn that certain features of a setup can increase the risk of a certain
> > type of failure, for example).
>
> The wheelbuilder, if he does things right, will not see a lot of failures. If he does see a lot of
> failures, there is no guarantee that he will learn from them if he does not understand the
> principles that govern how a wheel functions. Without understanding, he will misattribute cause
> and effect most likely.
>

I think you're missing my point. People will bring they're busted wheels to the wheelbuilder to fix.
So he sees busted wheels. And of course there is no guarantee that he will learn from them, why do
you even bother mentioning this? There was no guarantee that you'd clue in to what I was trying to
say either. I probably didn't explain my point well enough. Without understanding, he will be a bad
wheel builder. He builds wheels that fail too easily. People don't bring they're wheels back to the
crappy wheelbuilder to get fixed, they'll try another one (if they're good consumers). The good
wheelbuilder will see a lot of busted wheels, and over the years, he will notice that certain
practices are related to certain failures.

> I am not sure what your parenthetical statement is supposed to be an example of, nor how it
> relates to the prior clause. I don't know any wheelbuilders who use statistics, but I know many
> who use myth and lore.
>
What "clause" are you talking about? Can you dumb it down a bit for me, I'm not a lawyer.

> > The concrete pourer rarely sees a failure in his work.
>
> That's because the concrete is poured to spec based on well-known engineering principles. The
> pourer doesn't have to understand the principles.

Ya, but the analogy was that the concrete pourer knows when a strength element he's pouring is
designed properly because he's poured so many of them. Yes, hopefully the beam or column or slab or
whatever is built to spec, and I agree that the concrete builder doesn't have to understand the
principles. So....that's anohter reason why the analogy is a bad one. (the previous messages in the
thread might clear this up for you.) Thanks for building up my argument (albeit unintentionally).

 

[Sheldon Brown]

Peter Cole wrote:
> "Patrick Lamb" <[email protected]> wrote in message news:[email protected]...
>
>>Kenny Lee wrote:
>>
>>>Say, didn't some bike dudes invent the airplane at a place named Kitty Hawk, North Carolina. They
>>>weren't engineers were they?
>>
>>Are you kidding? Those guys probably wouldn't have known a partial differential equation if one
>>bit them!
>
>
> While formal engineering, especially aeronautical, didn't exist in their day, the Wright bros.
> certainly weren't the rube tinkerers that popular culture makes them out to be, they couldn't have
> been and still have solved the very difficult problems they did. To work out the problems of
> control and stable flight, they had to have a beyond state-of-the-art understanding of the physics
> and engineering involved.
>
> from : http://wright.nasa.gov/overview.htm
>
> Wright Brothers' Invention Process:
>
> The process which lead to the first successful airplane is exactly the same process used by NASA
> engineers today to solve problems.
>
> (1899 - 1902) - Researched How Things Fly
>
> The first step in any new program or project is research. The Wright Brothers first performed a
> literature search to find out the state of aeronautical knowledge at their time. They wrote to the
> Smithsonian and obtained technical papers regarding aerodynamics. They read about the works of
> Cayley, and Langley, and the hang-gliding flights of Otto Lilienthal.
>
> They corresponded with Octave Chanute concerning some of their ideas. They studied the problems
> which had been encountered by previous flyers and they talked about possible solutions to the
> problems. They looked for answers to the problems of flight by observing large gliding birds. They
> decided that control of the flying aircraft would be the most crucial and hardest problem to solve
> and they had some ideas for solving that problem.

Then, one day, one of them was idly fiddling with an empty bicycle inner tube box, twisting it back
and forth...when the proverbial light bulb went off, and he had the elusive solution to controlling
flight in the roll axis!

Sheldon "Orville Wright Signed My Father's Glider Pilot's License" Brown
+------------------------------------------+
| Genius is one per cent inspiration and | ninety-nine per cent perspiration. |
|. --Thomas Edison |
+------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

 

[Tim McNamara]

In article <[email protected]>, "SDB" <[email protected]> wrote:

> "Tim McNamara" <[email protected]> wrote in message
> news:[email protected]...
> > In article <[email protected]>, "SDB" <[email protected]>
> > wrote:
> >
> > > IMHO, the wheel builder/concrete pourer analogy is not a fair one. The wheel builder most
> > > likely sees a lot of failures and learns from them (using statistics, someone without
> > > knowledge of wheel mechanics can learn that certain features of a setup can increase the risk
> > > of a certain type of failure, for example).
> >
> > The wheelbuilder, if he does things right, will not see a lot of failures. If he does see a lot
> > of failures, there is no guarantee that he will learn from them if he does not understand the
> > principles that govern how a wheel functions. Without understanding, he will misattribute cause
> > and effect most likely.
>
> I think you're missing my point. People will bring they're busted wheels to the wheelbuilder to
> fix. So he sees busted wheels. And of course there is no guarantee that he will learn from them,
> why do you even bother mentioning this? There was no guarantee that you'd clue in to what I was
> trying to say either. I probably didn't explain my point well enough. Without understanding, he
> will be a bad wheel builder. He builds wheels that fail too easily. People don't bring they're
> wheels back to the crappy wheelbuilder to get fixed, they'll try another one (if they're good
> consumers).

IMHO that's a dumb consumer. If somebody sells you a sub-par item, hold them accountable for it. In
this case, make them pay for a competent wheelbuilder to do the job right.

> The good wheelbuilder will see a lot of busted wheels, and over the years, he will notice that
> certain practices are related to certain failures.

If he didn't build the wheels, he'll have little or no idea about what practices were or weren't
used. So he'll learn nothing by this other than the obvious "don't radially spoke wheels." The most
important featuer in wheelbuilding for longevity is stress relieving, and only the person who built
the wheel knows if it was done- whomever comes along next can't tell. The second builder might be
able to tell whether the wheel was properly tensioned, which certainly is important also but less
critical to spoke service life.

> > I am not sure what your parenthetical statement is supposed to be an example of, nor how it
> > relates to the prior clause. I don't know any wheelbuilders who use statistics, but I know many
> > who use myth and lore.
> >
> What "clause" are you talking about? Can you dumb it down a bit for me, I'm not a lawyer.

What does "(using statistics, someone without knowledge of wheel mechanics can learn that certain
features of a setup can increase the risk of a certain type of failure, for example)" have to do
with "The wheel builder most likely sees a lot of failures and learns from them"? I know of no
wheelbuilders- and I know a few after 30+ years as a bikie- who collect such data nor do statistical
analyses. Except perhaps Jobst, but I can't say that I know him since we've never met.

> > > The concrete pourer rarely sees a failure in his work.
> >
> > That's because the concrete is poured to spec based on well-known engineering principles. The
> > pourer doesn't have to understand the principles.
>
> Ya, but the analogy was that the concrete pourer knows when a strength element he's pouring is
> designed properly because he's poured so many of them.

There's no reason to make that assumption. The pourer is just as likely to misattribute cause and
effect. Repetition of wrong assumptions does not lead to knowledge.

> Yes, hopefully the beam or column or slab or whatever is built to spec, and I agree that the
> concrete builder doesn't have to understand the principles. So....that's anohter reason why the
> analogy is a bad one. (the previous messages in the thread might clear this up for you.) Thanks
> for building up my argument (albeit unintentionally).

I didn't build up your argument at all, intentionally or not.

 

[Sdb]

"Tim McNamara" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "SDB" <[email protected]> wrote:
>
> > "Tim McNamara" <[email protected]> wrote in message
> > news:[email protected]...
> > > In article <[email protected]>, "SDB" <[email protected]>
> > > wrote:
> > >
> > > > IMHO, the wheel builder/concrete pourer analogy is not a fair one. The wheel builder most
> > > > likely sees a lot of failures and learns from them (using statistics, someone without
> > > > knowledge of wheel mechanics can learn that certain features of a setup can increase the
> > > > risk of a certain type of failure, for example).
> > >
> > > The wheelbuilder, if he does things right, will not see a lot of failures. If he does see a
> > > lot of failures, there is no guarantee that he will learn from them if he does not understand
> > > the principles that govern how a wheel functions. Without understanding, he will misattribute
> > > cause and effect most likely.
> >
> > I think you're missing my point. People will bring they're busted wheels to the wheelbuilder to
> > fix. So he sees busted wheels. And of course there is no guarantee that he will learn from them,
> > why do you even bother mentioning this? There was no guarantee that you'd clue in to what I was
> > trying to say either. I probably didn't explain my point well enough. Without understanding, he
> > will be a bad wheel builder. He builds wheels that fail too easily. People don't bring they're
> > wheels back to the crappy wheelbuilder to get fixed, they'll try another one (if they're good
> > consumers).
>
> IMHO that's a dumb consumer. If somebody sells you a sub-par item, hold them accountable for it.
> In this case, make them pay for a competent wheelbuilder to do the job right.

Firstly, are you saying that a smart consumer would bring the wheel back to someone who he suspects
lacks the comptency to do the job? Give the mechanic a second chance to screw it up again? Doesn't
sound too smart to me. Secondly, you say he should make them pay for gettng the wheel fixed by a
competent wheel builder. So, the competent wheelbuilder would eventually see the busted wheel, as I
suggested would happen if it were a good consumer. I don't quite understand the point you are
trying to make.

>
> > The good wheelbuilder will see a lot of busted wheels, and over the years, he will notice that
> > certain practices are related to certain failures.
>
> If he didn't build the wheels, he'll have little or no idea about what practices were or weren't
> used. So he'll learn nothing by this other than the obvious "don't radially spoke wheels." The
> most important featuer in wheelbuilding for longevity is stress relieving, and only the person who
> built the wheel knows if it was done- whomever comes along next can't tell. The second builder
> might be able to tell whether the wheel was properly tensioned, which certainly is important also
> but less critical to spoke service life.
>

I think you've contradicted yourself. First you said he'd have little or no idea about the wheel,
but then you say he'd know about the tensioning. He'd also know about the type of spokes and
nipples, etc. He'd know more than nothing, I think.

> > > I am not sure what your parenthetical statement is supposed to be an example of, nor how it
> > > relates to the prior clause. I don't know any wheelbuilders who use statistics, but I know
> > > many who use myth and lore.
> > >
> > What "clause" are you talking about? Can you dumb it down a bit for me, I'm not a lawyer.
>
> What does "(using statistics, someone without knowledge of wheel mechanics can learn that certain
> features of a setup can increase the risk of a certain type of failure, for example)" have to do
> with "The wheel builder most likely sees a lot of failures and learns from them"? I know of no
> wheelbuilders- and I know a few after 30+ years as a bikie- who collect such data nor do
> statistical analyses. Except perhaps Jobst, but I can't say that I know him since we've never met.
>
I'm not suggesting that the wheel mechanic is doing a statistical analysis, or keeping creepy
records of all the wheel failures he's seen. But if he's good he's probably not stupid and
without the capacity to remember. If he sees enough of the same thing happening repeatedly, he'll
learn from it.

> > > > The concrete pourer rarely sees a failure in his work.
> > >
> > > That's because the concrete is poured to spec based on well-known engineering principles. The
> > > pourer doesn't have to understand the principles.
> >
> > Ya, but the analogy was that the concrete pourer knows when a strength element he's pouring is
> > designed properly because he's poured so many of them.
>
> There's no reason to make that assumption. The pourer is just as likely to misattribute cause and
> effect. Repetition of wrong assumptions does not lead to knowledge.

IT WASN:T MY ANALOGY. I WAS SAYING THAT THE ANALOGY WASN'T A GOOD ONE. I WAS ARGUING THAT THE
CONCRETE POURER SHOULDN'T MAKE ASSUMPTIONS ABOUT THE DESIGN BASED ON HIS EXPERIENCE OF
POURING CONCRETE.

>
> > Yes, hopefully the beam or column or slab or whatever is built to spec, and I agree that the
> > concrete builder doesn't have to understand the principles. So....that's anohter reason why the
> > analogy is a bad one. (the previous messages in the thread might clear this up for you.) Thanks
> > for building up my argument (albeit unintentionally).
>
> I didn't build up your argument at all, intentionally or not.

Actually, I don't think you've taken the time to understand what I've been trying to say.....

 

[Tim McNamara]

In article <[email protected]>, "SDB" <[email protected]> wrote:

> "Tim McNamara" <[email protected]> wrote in message
> news:[email protected]...
> > In article <[email protected]>, "SDB" <[email protected]> wrote:
> >
> > > I think you're missing my point. People will bring they're busted wheels to the wheelbuilder
> > > to fix. So he sees busted wheels. And of course there is no guarantee that he will learn from
> > > them, why do you even bother mentioning this? There was no guarantee that you'd clue in to
> > > what I was trying to say either. I probably didn't explain my point well enough. Without
> > > understanding, he will be a bad wheel builder. He builds wheels that fail too easily. People
> > > don't bring they're wheels back to the crappy wheelbuilder to get fixed, they'll try another
> > > one (if they're good consumers).
> >
> > IMHO that's a dumb consumer. If somebody sells you a sub-par item, hold them accountable for it.
> > In this case, make them pay for a competent wheelbuilder to do the job right.
>
> Firstly, are you saying that a smart consumer would bring the wheel back to someone who he
> suspects lacks the comptency to do the job? Give the mechanic a second chance to screw it up
> again? Doesn't sound too smart to me.

Yes, that's exactly what I'm saying. It's what a good consumer does- take it back to the person who
sold it to you and have them fix it properly, refund your money or pay for the repairs. Wouldn't
you do that with any other consumer goods- a television, a computer, a car? Hell, a pair of custom
built wheels can cost more than a TV, computer and some (used) cars. My bikes are always worth more
than my cars.

If you get ripped off by the bike shop (appliance store, computer store, car dealer) do you really
think it's a *smart* consumer who just goes and forks out the money for fixing the bike shop's error
to someone else? No, the smart consumer takes it back and gets satisfaction, rather than just
passively excusing incompetence.

> Secondly, you say he should make them pay for gettng the wheel fixed by a competent wheel builder.
> So, the competent wheelbuilder would eventually see the busted wheel, as I suggested would happen
> if it were a good consumer. I don't quite understand the point you are trying to make.

The point is that a smart consumer holds the seller accountable.

> > > The good wheelbuilder will see a lot of busted wheels, and over the years, he will notice that
> > > certain practices are related to certain failures.
> >
> > If he didn't build the wheels, he'll have little or no idea about what practices were or weren't
> > used. So he'll learn nothing by this other than the obvious "don't radially spoke wheels." The
> > most important featuer in wheelbuilding for longevity is stress relieving, and only the person
> > who built the wheel knows if it was done- whomever comes along next can't tell. The second
> > builder might be able to tell whether the wheel was properly tensioned, which certainly is
> > important also but less critical to spoke service life.
> >
>
> I think you've contradicted yourself. First you said he'd have little or no idea about the wheel,
> but then you say he'd know about the tensioning. He'd also know about the type of spokes and
> nipples, etc. He'd know more than nothing, I think.

He wouldn't be able to tell the crucial issues about whether the practices that promote wheel
longevity were used- e.g., stress relieving the spokes. Sorry, I thought that was obvious since you
said you know how wheels are built. The good wheelbuilder would be able to figure out a few things
(components and spoke tension), but he can't read minds and would have to guess about the most
important stuff.

> I'm not suggesting that the wheel mechanic is doing a statistical analysis, or keeping creepy
> records of all the wheel failures he's seen. But if he's good he's probably not stupid and without
> the capacity to remember. If he sees enough of the same thing happening repeatedly, he'll learn
> from it.

If he's exceptionally careful, methodical and analytical- and has some knowledge of metallurgy, the
engineering of pretensioned structures, etc.- then he might. If not, then he's likely to
misattribute cause and effect and decide that the wheel broke because it wasn't tied and soldered,
or the chicken ritual wasn't properly done, or whatever other bit of myth and lore he happens to
believe in.

> > > > > The concrete pourer rarely sees a failure in his work.
> > > >
> > > > That's because the concrete is poured to spec based on well-known engineering principles.
> > > > The pourer doesn't have to understand the principles.
> > >
> > > Ya, but the analogy was that the concrete pourer knows when a strength element he's pouring is
> > > designed properly because he's poured so many of them.
> >
> > There's no reason to make that assumption. The pourer is just as likely to misattribute cause
> > and effect. Repetition of wrong assumptions does not lead to knowledge.
>
> IT WASN:T MY ANALOGY. I WAS SAYING THAT THE ANALOGY WASN'T A GOOD ONE. I WAS ARGUING THAT THE
> CONCRETE POURER SHOULDN'T MAKE ASSUMPTIONS ABOUT THE DESIGN BASED ON HIS EXPERIENCE OF POURING
> CONCRETE.

No need to shout, dude. And, er, the original analogy was that the concrete pourer *does not* know
whether the prestressed concrete structure is properly designed just because he's poured a million
of them. So you're actually agreeing with the original analogy as stated by Jobst?

> > > Yes, hopefully the beam or column or slab or whatever is built to spec, and I agree that the
> > > concrete builder doesn't have to understand the principles. So....that's anohter reason why
> > > the analogy is a bad one. (the previous messages in the thread might clear this up for you.)
> > > Thanks for building up my argument (albeit unintentionally).
> >
> > I didn't build up your argument at all, intentionally or not.
>
> Actually, I don't think you've taken the time to understand what I've been trying to say.....

I can only read what you've actually written. I have no way of knowing what you're *trying* to say.

 

[Jennifer Donlea]

Jobst Brandt wrote:

> As I have often related, I ride on hubs and spokes that have been together for far more than
> 200,000miles over many years. Spokes are so far below their yield stress from loading that they
> should never fail.

I, like others, have had great success reusing spokes, and am now using a front wheel that's on its
third rim, the first two having worn out from braking! The weakness in this system, for me, is the
hub bearings, which are getting pitted. Did you replace the bearing cups on your 200,000 mile
wheels, or are you still using the original bearing cups? Or are my hub's bearing cups pitted from
overtightening of the bearing with the quick release, an error from my younger days? Or was it my
less-than-regular ball/grease replacement schedule?

Thanks!

Jennifer D

 

[Mike S.]

"Tim McNamara" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "Mike S." <mikeshaw2@coxDOTnet> wrote:
>
> > <[email protected]> wrote in message
> > news:[email protected]...
> > > Mike Shaw writes:
> > >
> > > > I know from personal experience that 15/16 butted spokes make too flexy a wheel for me.
> > > > Diving into corners in a criterium is not the place for a flexy front wheel, no matter how
> > > > durable or comfortable the ride. Other people that I know swear by
> > > > 15/16 spokes for all of their wheels.
> > >
> > > Now we are getting to the nature of your beliefs and that you have not seen the book that
> > > dissects all this in fine detail so that no stone should remain unturned, so to speak. You
> > > didn't say how many spokes you use on these "too flexy" wheels but from the implications, they
> > > are not 16 spoke wheels. Even if they were, you could not feel the elasticity of the spokes,
> > > these deflections being on the order of riding over a piece of copier bond paper, on the order
> > > of 0.004". Next time you ride over a sheet of paper and feel it, let me know about it.
> > >
> > Did YOU ride my wheels? Have you even SEEN my wheels? I built them, I rode them, and YES, they
> > were flexy. See, and you wonder why I question what engineers tell me. Tire pressure wasn't the
> > issue, it was 180# diving into corners and sprinting out of them that made them flex.
>
> Perhaps you should wonder about the veracity of your perceptions rather than what engineers tell
> you. HOW could you tell it was the wheels that were flexing? HOW did you isolate that from fork
> flex, frame flex, tire deformation? Do you understand that your wheels see basically no side
> loading in a corner, no matter how fast you are going, unless you keep the bike vertical while
> turning?
>

I noticed because I own multiple sets of wheels with various spoke counts, with various rims and
tires, and not all of my wheels flex noticeably. Right now, the Mavic/Open Pros/14/15 I'm riding
don't do what the Ultegra/Open Sups/15/16 did. I couldn't tell you if they were flexing or not.

I was racing my Cosmics the other weekend in Yuma in Saturday's RR. Those things ride way stiff. I
raced my Ritchey Pro wheels Sunday in the crit. Much softer ride. Whether it was spoke tension, rim
depth, or a combination, I don't know. All I know was that the two wheelsets rode completely
differently. Even more drastic was my experiment with Ti spokes when they first came out. Felt like
I was constantly riding a low tire. I used to keep looking back at my rear wheel, making sure that
the tire was still inflated. (I still have the spokes if someone wants to experiment with them)

In the wheels I'm talking about: my Ultegra/Open SUP CDs with the 15/16 spokes, I had just gotten
done working at the shop I was managing, and had pumped up the tires using the shop's compressor.
The tires weren't low and the road wasn't exceptionally wavy. When I was JRA, the wheels were some
of the nicest riding wheels I owned: they stayed round and true.

I will admit that sometimes I'm wrong: I was out the other day on my new Bontrager frame and was
noticing how comfy the ride was but it felt "dead." Went to go ride the next day, and lo and behold,
the tires were low. Pumped them back up to 110, and the ride was different. Go figure. Yes, I
realize that this admission brings doubts into what I've been saying. I know if I'm wrong, I'm man
enough to admit it.

Its too bad those wheels got sold on my M2, otherwise I'd have say, Jon, come over and try them out.

Mike

> You built them, you say? The only way for pretensioned spoked wheels to be flexy (so that it's
> noticeable- the top of your rear wheel flexes 1 to 2 mm to the left every time you mash down the
> pedals while climbing, but no one notices this by feel) is if the spokes are massively
> undertensioned.

Its not the rear wheel that was being the problem, it was the front.
>
> Frankly, if your wheels flexed enough to be felt while cornering, the wheel was dangerously close
> to collapse and would probably have gone all the way to failure.
>
> > I agree that just riding along in a straight line, I'm not going to feel the spokes elongate.
> > Sprinting and cornering on the above-mentioned wheels is a completely different story.
>
> I'd guess you need to learn how to properly tension a wheel, from your description.
>
> FWIW, I'm not an engineer. I've built hundreds of wheels in my days as a bike shop wrench and for
> friends since I got a job that actually pays the bills. I raced for 10 years. I am 6'4" and
> weighed about 195 lbs throughout my racing career. I never had a wheel flex noticeably. No one
> else I know has ever complained about wheels flexing.

 

[Jobst Brandt]

Jennifer Donleavy writes:

>> As I have often related, I ride on hubs and spokes that have been together for far more than
>> 200,000miles over many years. Spokes are so far below their yield stress from loading that they
>> should never fail.

> I, like others, have had great success reusing spokes, and am now using a front wheel that's on
> its third rim, the first two having worn out from braking! The weakness in this system, for me, is
> the hub bearings, which are getting pitted. Did you replace the bearing cups on your 200,000 mile
> wheels, or are you still using the original bearing cups? Or are my hub's bearing cups pitted from
> overtightening of the bearing with the quick release, an error from my younger days? Or was it my
> less-than-regular ball/grease replacement schedule?

I replaced the cups once, but that was more a function of water in the bearings from high speed
descending in rain than pitting from use. I take spare bearing balls along on my tours in the Alps
for just that reason. Cones don't last as long because they have a smaller radius and contact area.
It's not as tough these are the hubs that I would design, but rather ones that are/were commercially
available. Maybe some day I can get someone to make labyrinth sealed hubs, seals like we find only
on Sturmey Archer gear hubs. You'll find that on disassembly these hubs are always clean inside even
though they are 50 years old.

That's one of the few things than SA did right.

Jobst Brandt [email protected] Palo Alto CA

 

[Terry Morse]

Jobst Brandt wrote:

> Maybe some day I can get someone to make labyrinth sealed hubs, seals like we find only on Sturmey
> Archer gear hubs. You'll find that on disassembly these hubs are always clean inside even though
> they are 50 years old.

How much mileage do folks get out of Phil Wood hub bearings? I've never been inclined to try them,
but I know some long distance riders who swear by them for wet conditions.
--
terry morse Palo Alto, CA http://www.terrymorse.com/bike/

 

[Tim McNamara]

In article <[email protected]>, John Everett
<[email protected]> wrote:

> On Sat, 01 Mar 2003 23:08:39 +0800, Kenny Lee <[email protected]> wrote:
>
> >Say, didn't some bike dudes invent the airplane at a place named Kitty Hawk, North Carolina. They
> >weren't engineers were they?
>
> Actually, no; they invented it at a place named Dayton, Ohio.

Yah, they just flew it at Kitty Hawk.

> They also were among the world's first aeronautical engineers. While they didn't have BSAEs, the
> reseach they performed (including extensive wind-tunnel testing) certainly qualifies as
> engineering.

ISTR that the "wind tunnel testing" used by Orville and Wilbur was models mounted on the handlebars
of their bikes.

 

[Tim McNamara]

In article <[email protected]>, "Mike S." <mikeshaw2@coxDOTnet> wrote:

> "Tim McNamara" <[email protected]> wrote in message
> news:[email protected]...

<snip>

> > You built them, you say? The only way for pretensioned spoked wheels to be flexy (so that it's
> > noticeable- the top of your rear wheel flexes 1 to 2 mm to the left every time you mash down the
> > pedals while climbing, but no one notices this by feel) is if the spokes are massively
> > undertensioned.
>
> Its not the rear wheel that was being the problem, it was the front.

Yeah, I was guessing that was the case, since you were talking about cornering in a crit. I was just
pointing out that the only regular wheel flex that most riders experience goes unnoticed by almost
all; that flex comes are a consequence of the torque input from pedalling.

The thing about cornering is that you lean the bike into the corner at speed, so that virtually all
the loading is still vertical from the wheels perspective. Side loading (in normal cornering) is
negligible on a bicycle wheel, unless you adhere to the Mike Walden "lean the rider not the bike"
school and you're keeping the bike as close to vertical as you can in corners. On tighter corners,
the wheels are in two planes so there's possibly some very slight side loads; on wider corners, the
wheels are practically in the same plane- in either case these are negligible forces.

So I'm not sure where the flex you say you experienced would be coming from. Grossly
undertensioned wheels, I can see, but I'd doubt that you'd be riding those. Are the tires the same
on all these wheels?

 

[Tim McNamara]

In article <[email protected]>, Terry Morse <[email protected]> wrote:

> Jobst Brandt wrote:
>
> > Maybe some day I can get someone to make labyrinth sealed hubs, seals like we find only on
> > Sturmey Archer gear hubs. You'll find that on disassembly these hubs are always clean inside
> > even though they are 50 years old.
>
> How much mileage do folks get out of Phil Wood hub bearings? I've never been inclined to try them,
> but I know some long distance riders who swear by them for wet conditions.

I've got 18-20,000 miles on my set and they spin between the fingers smoothly just like new. But
they have not had a lot of rain exposure and I would expect some problems if I did.

 

[Jobst Brandt]

Terry Morse writes:

>> Maybe some day I can get someone to make labyrinth sealed hubs, seals like we find only on
>> Sturmey Archer gear hubs. You'll find that on disassembly these hubs are always clean inside even
>> though they are 50 years old.

> How much mileage do folks get out of Phil Wood hub bearings? I've never been inclined to try them,
> but I know some long distance riders who swear by them for wet conditions.

People swear by all sorts of things but a contact face lip seal is not reliable for taht use.
Typically seals on automobiles are used to keep oil IN and are protected by a labyrinth from water.
There are two rules of seals that bicycle "sealed bearings" violate.

1. No two liquids can be reasonably separated by a single contact lip.

2. A contact lip seal that doesn't leak, leaks.

The second bears on the first. If the retained fluid does not seep under the lip, the seal lip will
go dry and burn away its preload for lack of lubrication, thereby becoming a capillary for external
water in the case of the bicycle. If there is water on one side and oil on the other, the two will
mix under the lip. Separating two fluids requires two lips with a vent between to make sure the
interstitial does not fill with one or the other fluid. Typically an automatic transmission oil on a
Corvair and its Hypoid oil required two seals.

Bicycle people do not come from a background of tribology and have no idea what that is all about. I
find it surprising that SA hubs were designed with labyrinth seals but then New Departure coaster
brakes also had such a seal. It seems there were still skilled engineers employed in the bicycle
business in the early 20th century.

The Phil Wood hub was a great disservice to bicycling when it introduced electric motor shaft
bearings with air flow seals posing as water seals. Unfortunately, the bicycle industry, not knowing
much about seals went head over heels to imitate this "great success."

Electric motors that are natural air pumps (that's how they cool themselves) use simple lip face
seals to prevent air being sucked through the shaft bearings, the natural low pressure zone, and gum
up the bearing grease with atmospheric dust. These seals were never intended to seal the bearing
against water although most people believe they can do that. This may be true for an occasional
splash, but hydrostatic water pressure will go into the bearing.

Jobst Brandt [email protected] Palo Alto CA