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Cup & Cone Bottom Brackets - Any Sources?



 
 
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  #31  
Old April 1st 08, 08:33 AM posted to rec.bicycles.tech
Ben C
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Posts: 3,084
Default Cup & Cone Bottom Brackets - Any Sources?

On 2008-04-01, Jay Beattie wrote:
On Mar 31, 5:10*pm, John Thompson wrote:
On 2008-03-31, Tom Sherman wrote:

John Thompson wrote:


How do you "wear out" a frame? Damage, yes -- either through neglect or
abuse, or what have you. But "wear out?"
Corrosion (metal frames),


I'd file that under "neglect."

fatigue (metal and composite)


Not an issue with a properly designed steel frame, but certainly a
potential issue with aluminum. I'm not aware of composites having
fatigue failures, but I may just be ignorant on that point.

and degradation of epoxy and adhesives (composite).


Disposable frames, then. I'll stick with steel, thank you.


Steel as a material has an infinite fatigue life with the loads
applied by whimpy cyclists, but as actually used in bicycle frames, it
does not -- at least based on my experience.


I think what Jim was saying was only some kinds of steel have an
infinite fatigue life (or "no endurance limit"). I think it's mild steel
that does. So maybe a $60 Roadmaster Fury has an infinite fatigue life
below some load. If so someone should tell their marketing department.

The steel used for decent bikes is different alloys, with
cleverly-designed impurities in it (and maybe more carbon?) which make
it stronger but mean it does fatigue eventually just like aluminium,
whatever the load.

You might think "no endurance limit" meant "endures forever", but it
doesn't, it means "no stress below which you don't get any fatigue".
Ads
  #32  
Old April 1st 08, 10:52 PM posted to rec.bicycles.tech
Michael Press
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Posts: 9,202
Default Cup & Cone Bottom Brackets - Any Sources?

In article ,
jim beam wrote:

Michael Press wrote:
In article ,
still just me wrote:

On Fri, 28 Mar 2008 22:28:35 -0700, jim beam
wrote:

otoh, by not simply replacing a worn out frame, you're deliberately
avoiding bothering to research improvements in frame design such as
over-size tube which help mitigate shimmy. or aluminum. or carbon. as
someone that like to express opinion on these materials, the least you
should do is bother to actually use them.
otooh, but fixing a frame that is otherwise still serviceable he not
only avoids wasting resources but keeps a valued old friend by his
side for years to come.

Not everyone buys into the throwaway world or has to always run with
the supposedly latest and greatest.

Of course, since you're goal wasn't really to comment intelligently on
the thread, but instead just to flame Jobst, I guess that's
irrelevant.


jim beam is a salesman in the `real world.'


gosh, the terrible things bored people will say when having a slow day.
only 3,418,427 unread web pages between you and being able to not be a
schmuck in public.


Is it something I said?

--
Michael Press
  #33  
Old April 2nd 08, 03:51 AM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 3,751
Default Cup & Cone Bottom Brackets - Any Sources?

John Thompson wrote:

Steel as a material has an infinite fatigue life with the loads
applied by whimpy cyclists, but as actually used in bicycle frames,
it does not -- at least based on my experience. I have cracked a
number of steel frames -- probably due to overheating of the lugs
or some other glitch in fabrication. My longest surviving high
mileage frame is a 1986 Cannondale T1000. That's old school
aluminum. I am not so sure about the new stuff.


My oldest frames are a couple of steel Atalas from the early 70s
(1970 and 1972). The older one is built up as my daily commuting
bike, the other is a fixed gear I ride 100 or so miles a week spring
through autumn. The older Atala failed at the BB/seat tube joint 20
some years ago, probably due to a cheap pressed BB shell. The
failure was a crack that extended all the way around the base of the
seat tube socket. The seat tube itself was not involved, so I was
able to sweat the old shell off and braze in a nice investment cast
shell to replace it. It's been going strong ever since.


Well that still doesn't answer the question about how many miles "old"
the bicycle is. I generally ride 10,000 miles per year according to
my odometer, so a 20 year old frame has some significant miles on it.
The only frame fatigue failures I have experienced were with Cinelli
style (sloping) fork crowns that typically have internal lugs that
cannot be feathered at the transition to the fork blades. They broke
exactly where the fork crown ended in the fork blade. Since then I
have stayed away from such forks that seem to have taken over nearly
all major brands that used brazed fork crowns. Too bad. It was a
stylishly bad mechanical design.

Other than that, I had plenty of crank fatigue failures, about one
every year or more until I modified that interface to a more
reasonable design, of a tapered conical seat instead of the fretting
flat faced pedal axle that augers itself into the crank until failure.
Since modification I have ridden Shimano cranks from that era but with
modification and haven't had a failure since.

Jobst Brandt
  #34  
Old April 2nd 08, 06:25 AM posted to rec.bicycles.tech
jim beam
external usenet poster
 
Posts: 5,758
Default Cup & Cone Bottom Brackets - Any Sources?

Michael Press wrote:
In article ,
jim beam wrote:

Michael Press wrote:
In article ,
still just me wrote:

On Fri, 28 Mar 2008 22:28:35 -0700, jim beam
wrote:

otoh, by not simply replacing a worn out frame, you're deliberately
avoiding bothering to research improvements in frame design such as
over-size tube which help mitigate shimmy. or aluminum. or carbon. as
someone that like to express opinion on these materials, the least you
should do is bother to actually use them.
otooh, but fixing a frame that is otherwise still serviceable he not
only avoids wasting resources but keeps a valued old friend by his
side for years to come.

Not everyone buys into the throwaway world or has to always run with
the supposedly latest and greatest.

Of course, since you're goal wasn't really to comment intelligently on
the thread, but instead just to flame Jobst, I guess that's
irrelevant.
jim beam is a salesman in the `real world.'

gosh, the terrible things bored people will say when having a slow day.
only 3,418,427 unread web pages between you and being able to not be a
schmuck in public.


Is it something I said?


yes, you said a great deal.

1. that you're bored.

2. that you regard try picking a fight as somehow entertaining.

3. that you hold your employers time in contempt since you're posting
during the hours they pay you to be doing other things.

4. that you have no guilt for making negative or false presumption.

5. that you have no guilt for using presumption to provoke. [see point
4 above.]

6. that you need no provocation yourself.

7. that you're so slow-witted that it takes you the better part of a day
to think up a response when your provocation gets a reaction.

i could go on, but further analysis of something best summarized as
"schmuck" is boring.
  #35  
Old April 2nd 08, 06:25 AM posted to rec.bicycles.tech
jim beam
external usenet poster
 
Posts: 5,758
Default Cup & Cone Bottom Brackets - Any Sources?

John Thompson wrote:
On 2008-04-01, jim beam wrote:

still just me wrote:


but fixing a frame that is otherwise still serviceable he not
only avoids wasting resources but keeps a valued old friend by his
side for years to come.


nonsensical claptrap.


How so? It makes sense to me.

i really don't give a flying one about who says what. i state the
facts. repairing an old frame with known flaws is a failed opportunity
to gain first hand experience of improvements that have occurred in the
last 3+ decades of frame design and manufacture.


For a top notch racer that might be an issue. But for most riders and
bikes, the improvements in frame design and manufacturing of the last
several decades are much less compelling. And I suspect many more people
fall into the latter category than the former.


most anyone can achieve sufficient speed downhill to experience shimmy
on a large frame steel tube bike. small frame users may not view this
as a concern since their frames don't have this problem as frequently,
but those of us that use big frames find this to be a big deal. and
it's one easily solved on modern frames with big tubes and thus higher
torsional stiffness. i think that to dismiss this as "much less
compelling" is failure to understand the issue, and more, inability to
understand how easily it is solved.
  #36  
Old April 2nd 08, 06:35 AM posted to rec.bicycles.tech
jim beam
external usenet poster
 
Posts: 5,758
Default Cup & Cone Bottom Brackets - Any Sources?

wrote:
John Thompson wrote:

Steel as a material has an infinite fatigue life with the loads
applied by whimpy cyclists, but as actually used in bicycle frames,
it does not -- at least based on my experience. I have cracked a
number of steel frames -- probably due to overheating of the lugs
or some other glitch in fabrication. My longest surviving high
mileage frame is a 1986 Cannondale T1000. That's old school
aluminum. I am not so sure about the new stuff.


My oldest frames are a couple of steel Atalas from the early 70s
(1970 and 1972). The older one is built up as my daily commuting
bike, the other is a fixed gear I ride 100 or so miles a week spring
through autumn. The older Atala failed at the BB/seat tube joint 20
some years ago, probably due to a cheap pressed BB shell. The
failure was a crack that extended all the way around the base of the
seat tube socket. The seat tube itself was not involved, so I was
able to sweat the old shell off and braze in a nice investment cast
shell to replace it. It's been going strong ever since.


Well that still doesn't answer the question about how many miles "old"
the bicycle is. I generally ride 10,000 miles per year according to
my odometer, so a 20 year old frame has some significant miles on it.
The only frame fatigue failures I have experienced were with Cinelli
style (sloping) fork crowns that typically have internal lugs that
cannot be feathered at the transition to the fork blades. They broke
exactly where the fork crown ended in the fork blade. Since then I
have stayed away from such forks that seem to have taken over nearly
all major brands that used brazed fork crowns. Too bad. It was a
stylishly bad mechanical design.

Other than that, I had plenty of crank fatigue failures, about one
every year or more until I modified that interface to a more
reasonable design, of a tapered conical seat instead of the fretting
flat faced pedal axle that augers itself into the crank until failure.
Since modification I have ridden Shimano cranks from that era but with
modification and haven't had a failure since.


your modification is to the pedal eye. cranks used to break at the
spider, the arm, and the pedal eye. these days, they hardly ever break
at any of these locations. that's because of superior design and
metallurgy. if your modification eliminated pedal eye failure, arm and
spider failure rates would continue unaffected and thus they would
continue to break frequently, which they don't.

conclusion: your pedal eye modification is irrelevant since others have
solved the problems for you. much like vacuum degassed stainless spoke
steels solved the spoke fatigue problems you were alleging to have also
"cured".
  #37  
Old April 2nd 08, 06:38 AM posted to rec.bicycles.tech
jim beam
external usenet poster
 
Posts: 5,758
Default Cup & Cone Bottom Brackets - Any Sources?

Ben C wrote:
On 2008-04-01, Jay Beattie wrote:
On Mar 31, 5:10�pm, John Thompson wrote:
On 2008-03-31, Tom Sherman wrote:

John Thompson wrote:
How do you "wear out" a frame? Damage, yes -- either through neglect or
abuse, or what have you. But "wear out?"
Corrosion (metal frames),
I'd file that under "neglect."

fatigue (metal and composite)
Not an issue with a properly designed steel frame, but certainly a
potential issue with aluminum. I'm not aware of composites having
fatigue failures, but I may just be ignorant on that point.

and degradation of epoxy and adhesives (composite).
Disposable frames, then. I'll stick with steel, thank you.

Steel as a material has an infinite fatigue life with the loads
applied by whimpy cyclists, but as actually used in bicycle frames, it
does not -- at least based on my experience.


I think what Jim was saying was only some kinds of steel have an
infinite fatigue life (or "no endurance limit").


that's muddled.

an endurance limit is where infinite fatigue life is demonstrated.


I think it's mild steel
that does.


correct.


So maybe a $60 Roadmaster Fury has an infinite fatigue life
below some load. If so someone should tell their marketing department.

The steel used for decent bikes is different alloys, with
cleverly-designed impurities in it (and maybe more carbon?) which make
it stronger but mean it does fatigue eventually just like aluminium,
whatever the load.


correct.



You might think "no endurance limit" meant "endures forever", but it
doesn't, it means "no stress below which you don't get any fatigue".


endurance limit, is the maximum cyclical load at which you can still
achieve infinite fatigue life.
  #38  
Old April 2nd 08, 08:24 AM posted to rec.bicycles.tech
Ben C
external usenet poster
 
Posts: 3,084
Default Cup & Cone Bottom Brackets - Any Sources?

On 2008-04-02, jim beam wrote:
Ben C wrote:
On 2008-04-01, Jay Beattie wrote:
On Mar 31, 5:10?pm, John Thompson wrote:
On 2008-03-31, Tom Sherman wrote:

John Thompson wrote:
How do you "wear out" a frame? Damage, yes -- either through neglect or
abuse, or what have you. But "wear out?"
Corrosion (metal frames),
I'd file that under "neglect."

fatigue (metal and composite)
Not an issue with a properly designed steel frame, but certainly a
potential issue with aluminum. I'm not aware of composites having
fatigue failures, but I may just be ignorant on that point.

and degradation of epoxy and adhesives (composite).
Disposable frames, then. I'll stick with steel, thank you.
Steel as a material has an infinite fatigue life with the loads
applied by whimpy cyclists, but as actually used in bicycle frames, it
does not -- at least based on my experience.


I think what Jim was saying was only some kinds of steel have an
infinite fatigue life (or "no endurance limit").


that's muddled.


Correct. I always get that muddled.

an endurance limit is where infinite fatigue life is demonstrated.


I think it's mild steel
that does.


correct.


So maybe a $60 Roadmaster Fury has an infinite fatigue life
below some load. If so someone should tell their marketing department.

The steel used for decent bikes is different alloys, with
cleverly-designed impurities in it (and maybe more carbon?) which make
it stronger but mean it does fatigue eventually just like aluminium,
whatever the load.


correct.



You might think "no endurance limit" meant "endures forever", but it
doesn't, it means "no stress below which you don't get any fatigue".


endurance limit, is the maximum cyclical load at which you can still
achieve infinite fatigue life.


Yes, so if you have no endurance limit, then you can't have infinite
fatigue life.
  #39  
Old April 2nd 08, 02:09 PM posted to rec.bicycles.tech
jim beam
external usenet poster
 
Posts: 5,758
Default Cup & Cone Bottom Brackets - Any Sources?

Ben C wrote:
On 2008-04-02, jim beam wrote:
Ben C wrote:
On 2008-04-01, Jay Beattie wrote:
On Mar 31, 5:10?pm, John Thompson wrote:
On 2008-03-31, Tom Sherman wrote:

John Thompson wrote:
How do you "wear out" a frame? Damage, yes -- either through neglect or
abuse, or what have you. But "wear out?"
Corrosion (metal frames),
I'd file that under "neglect."

fatigue (metal and composite)
Not an issue with a properly designed steel frame, but certainly a
potential issue with aluminum. I'm not aware of composites having
fatigue failures, but I may just be ignorant on that point.

and degradation of epoxy and adhesives (composite).
Disposable frames, then. I'll stick with steel, thank you.
Steel as a material has an infinite fatigue life with the loads
applied by whimpy cyclists, but as actually used in bicycle frames, it
does not -- at least based on my experience.
I think what Jim was saying was only some kinds of steel have an
infinite fatigue life (or "no endurance limit").

that's muddled.


Correct. I always get that muddled.

an endurance limit is where infinite fatigue life is demonstrated.


I think it's mild steel
that does.

correct.


So maybe a $60 Roadmaster Fury has an infinite fatigue life
below some load. If so someone should tell their marketing department.

The steel used for decent bikes is different alloys, with
cleverly-designed impurities in it (and maybe more carbon?) which make
it stronger but mean it does fatigue eventually just like aluminium,
whatever the load.

correct.


You might think "no endurance limit" meant "endures forever", but it
doesn't, it means "no stress below which you don't get any fatigue".

endurance limit, is the maximum cyclical load at which you can still
achieve infinite fatigue life.


Yes, so if you have no endurance limit, then you can't have infinite
fatigue life.


correct.

there is a mechanism for this too, it's not a random phenomenon. in low
strength steel alloys, it's associated with solute carbon atoms being
able to diffuse into the lattice voids of dislocations and "lock" them
in place. [no dislocation movement, no fatigue.] in some titanium
alloys, the same phenomenon exists with diffusing oxygen atoms.
  #40  
Old April 2nd 08, 10:39 PM posted to rec.bicycles.tech
Michael Press
external usenet poster
 
Posts: 9,202
Default Cup & Cone Bottom Brackets - Any Sources?

In article ,
jim beam wrote:

Michael Press wrote:
In article ,
jim beam wrote:

Michael Press wrote:
In article ,
still just me wrote:

On Fri, 28 Mar 2008 22:28:35 -0700, jim beam
wrote:

otoh, by not simply replacing a worn out frame, you're deliberately
avoiding bothering to research improvements in frame design such as
over-size tube which help mitigate shimmy. or aluminum. or carbon. as
someone that like to express opinion on these materials, the least you
should do is bother to actually use them.
otooh, but fixing a frame that is otherwise still serviceable he not
only avoids wasting resources but keeps a valued old friend by his
side for years to come.

Not everyone buys into the throwaway world or has to always run with
the supposedly latest and greatest.

Of course, since you're goal wasn't really to comment intelligently on
the thread, but instead just to flame Jobst, I guess that's
irrelevant.
jim beam is a salesman in the `real world.'

gosh, the terrible things bored people will say when having a slow day.
only 3,418,427 unread web pages between you and being able to not be a
schmuck in public.


Is it something I said?


yes, you said a great deal.

1. that you're bored.

2. that you regard try picking a fight as somehow entertaining.

3. that you hold your employers time in contempt since you're posting
during the hours they pay you to be doing other things.

4. that you have no guilt for making negative or false presumption.

5. that you have no guilt for using presumption to provoke. [see point
4 above.]

6. that you need no provocation yourself.

7. that you're so slow-witted that it takes you the better part of a day
to think up a response when your provocation gets a reaction.

i could go on, but further analysis of something best summarized as
"schmuck" is boring.


But you are a salesman, so why all the howling?

--
Michael Press
 




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