Bridge behind BB housing

sergio said:

I have recorded differring opinions from two different, famous!,
framebuilders,
whose identity I shall provisionally withold, about the usefulness of
having a bridge just behind the bottom bracket housing in a steel
frame.

Opinion n.1
It must be there to make the frame stronger; plus, it is so cheap.

Opinion n.2
It should not be there (unless one wants to attach fenders to it). It
makes the frame prone to cracking around the area where the bridge is
attached, more so than it would be around the BB housing.

Any learned opinion from you, expert builders?

As a guy who replaces cracked chainstays regularly, it isn't all that
simple. After about 1977/1980, with cast BB shells, short chainstays
(which must be dented or ovalled more deeply), and thinner tubes, all of
which contribute, a pretty cast bridge can lead to chainstay cracks.
Those cast pieces are big (in terms of BTUs and braze time) then are
quite rigid and they often have squared sharp edges. A simple thin tube
is less likely to give any trouble.

Some builders such as 3Rensho used a small 'plate' extension behind the
BB, others added a 'rib' on the shell casting between the chainstays and
many builders simply skipped the thing entirely. All of those avoid
chainstay cracks pretty well.

Mounting mudguards on my fixie was harder without a chainstay bridge,
yes, but it was Jobst Brandt who pointed to the now-obvious problem of
tires wedging at wheel change. If you can live with that, leave it out.

I do not believe a closed figure (axle/QR, chainstays, BB shell) is
affected by that bridge or lack of it in any real sense of strength or
rigidity.

We can follow a history of breakage from the bikes of the early sixties
with fork blade/crown failures to the later lower headlug/downtube
cracks on until cast-BB-with-the-wrong angles breakage, then chainstay
at bridge cracks to later cast frame end failure. The designers got
after each problem in turn. Making one piece in a dynamic figure
ultra-rigid doesn't always solve problems and sometimes makes new ones.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi said:

sergio said:

I have recorded differring opinions from two different, famous!,
framebuilders,
whose identity I shall provisionally withold, about the usefulness of
having a bridge just behind the bottom bracket housing in a steel
frame.

Quoted message said:

Opinion n.1
It must be there to make the frame stronger; plus, it is so cheap.

Quoted message said:

Opinion n.2
It should not be there (unless one wants to attach fenders to it). It
makes the frame prone to cracking around the area where the bridge is
attached, more so than it would be around the BB housing.

Quoted message said:

Any learned opinion from you, expert builders?

As a guy who replaces cracked chainstays regularly, it isn't all that
simple. After about 1977/1980, with cast BB shells, short chainstays
(which must be dented or ovalled more deeply), and thinner tubes, all of
which contribute, a pretty cast bridge can lead to chainstay cracks.
Those cast pieces are big (in terms of BTUs and braze time) then are
quite rigid and they often have squared sharp edges. A simple thin tube
is less likely to give any trouble.

Some builders such as 3Rensho used a small 'plate' extension behind the
BB, others added a 'rib' on the shell casting between the chainstays and
many builders simply skipped the thing entirely. All of those avoid
chainstay cracks pretty well.

Mounting mudguards on my fixie was harder without a chainstay bridge,
yes, but it was Jobst Brandt who pointed to the now-obvious problem of
tires wedging at wheel change. If you can live with that, leave it out.

I do not believe a closed figure (axle/QR, chainstays, BB shell) is
affected by that bridge or lack of it in any real sense of strength or
rigidity.

We can follow a history of breakage from the bikes of the early sixties
with fork blade/crown failures to the later lower headlug/downtube
cracks on until cast-BB-with-the-wrong angles breakage, then chainstay
at bridge cracks to later cast frame end failure. The designers got
after each problem in turn. Making one piece in a dynamic figure
ultra-rigid doesn't always solve problems and sometimes makes new ones.

What was the deal with headlug/downtube joint? That seems like a
pretty benign joint. -- Jay Beattie.

A Muzi said:

As a guy who replaces cracked chainstays regularly, it isn't all that
simple. After about 1977/1980, with cast BB shells, short chainstays
(which must be dented or ovalled more deeply), and thinner tubes, all of
which contribute, a pretty cast bridge can lead to chainstay cracks.
Those cast pieces are big (in terms of BTUs and braze time) then are
quite rigid and they often have squared sharp edges. A simple thin tube
is less likely to give any trouble.

A piece of 1/2" electrical conduit works just fine. You can buy enough
for 50 frames for a couple bucks at the hardware store.

Quoted message said:

Some builders such as 3Rensho used a small 'plate' extension behind the
BB, others added a 'rib' on the shell casting between the chainstays and
many builders simply skipped the thing entirely. All of those avoid
chainstay cracks pretty well.

Some people claim the bridge stiffens the rear triangle. I've built and
ridden frames with and without and frankly, I can't tell a difference.

--

John ([email hidden])

sergio said:

I have recorded differring opinions from two different, famous!,
framebuilders,
whose identity I shall provisionally withold, about the usefulness of
having a bridge just behind the bottom bracket housing in a steel
frame.

Opinion n.1
It must be there to make the frame stronger; plus, it is so cheap.

Opinion n.2
It should not be there (unless one wants to attach fenders to it). It
makes the frame prone to cracking around the area where the bridge is
attached, more so than it would be around the BB housing.

Any learned opinion from you, expert builders?

Sergio
Pisa

I am not an expert, but I have seen such bridges on many track bikes, as
well as a few road bikes, and I've never seen one of them with cracked
chainstays.

Quoted message said:

Quoted message said:

sergio said:

I have recorded differring opinions from two different, famous!,
framebuilders,
whose identity I shall provisionally withold, about the usefulness of
having a bridge just behind the bottom bracket housing in a steel
frame.
Opinion n.1
It must be there to make the frame stronger; plus, it is so cheap.
Opinion n.2
It should not be there (unless one wants to attach fenders to it). It
makes the frame prone to cracking around the area where the bridge is
attached, more so than it would be around the BB housing.
Any learned opinion from you, expert builders?

Quoted message said:

A Muzi <[email hidden]> blathered:

Quoted message said:

As a guy who replaces cracked chainstays regularly, it isn't all that
simple. After about 1977/1980, with cast BB shells, short chainstays
(which must be dented or ovalled more deeply), and thinner tubes, all of
which contribute, a pretty cast bridge can lead to chainstay cracks.
Those cast pieces are big (in terms of BTUs and braze time) then are
quite rigid and they often have squared sharp edges. A simple thin tube
is less likely to give any trouble.
Some builders such as 3Rensho used a small 'plate' extension behind the
BB, others added a 'rib' on the shell casting between the chainstays and
many builders simply skipped the thing entirely. All of those avoid
chainstay cracks pretty well.
Mounting mudguards on my fixie was harder without a chainstay bridge,
yes, but it was Jobst Brandt who pointed to the now-obvious problem of
tires wedging at wheel change. If you can live with that, leave it out.
I do not believe a closed figure (axle/QR, chainstays, BB shell) is
affected by that bridge or lack of it in any real sense of strength or
rigidity.
We can follow a history of breakage from the bikes of the early sixties
with fork blade/crown failures to the later lower headlug/downtube
cracks on until cast-BB-with-the-wrong angles breakage, then chainstay
at bridge cracks to later cast frame end failure. The designers got
after each problem in turn. Making one piece in a dynamic figure
ultra-rigid doesn't always solve problems and sometimes makes new ones.

Jay Beattie said:

What was the deal with headlug/downtube joint? That seems like a
pretty benign joint. -- Jay Beattie.

Ideally, the joint is brazed tube-to-tube with the lug supporting that
joint. A straight-angled chop or two at the downtube can't mate
properly to the head tube.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi said:

Quoted message said:

Quoted message said:

sergio wrote:
> I have recorded differring opinions from two different, famous!,
> framebuilders,
> whose identity I shall provisionally withold, about the usefulness of
> having a bridge just behind the bottom bracket housing in a steel
> frame.
> Opinion n.1
> It must be there to make the frame stronger; plus, it is so cheap.
> Opinion n.2
> It should not be there (unless one wants to attach fenders to it). It
> makes the frame prone to cracking around the area where the bridge is
> attached, more so than it would be around the BB housing.
> Any learned opinion from you, expert builders?

Quoted message said:

A Muzi <[email hidden]> blathered:

Quoted message said:

As a guy who replaces cracked chainstays regularly, it isn't all that
simple. After about 1977/1980, with cast BB shells, short chainstays
(which must be dented or ovalled more deeply), and thinner tubes, all of
which contribute, a pretty cast bridge can lead to chainstay cracks.
Those cast pieces are big (in terms of BTUs and braze time) then are
quite rigid and they often have squared sharp edges. A simple thin tube
is less likely to give any trouble.
Some builders such as 3Rensho used a small 'plate' extension behind the
BB, others added a 'rib' on the shell casting between the chainstays and
many builders simply skipped the thing entirely. All of those avoid
chainstay cracks pretty well.
Mounting mudguards on my fixie was harder without a chainstay bridge,
yes, but it was Jobst Brandt who pointed to the now-obvious problem of
tires wedging at wheel change. If you can live with that, leave it out.
I do not believe a closed figure (axle/QR, chainstays, BB shell) is
affected by that bridge or lack of it in any real sense of strength or
rigidity.
We can follow a history of breakage from the bikes of the early sixties
with fork blade/crown failures to the later lower headlug/downtube
cracks on until cast-BB-with-the-wrong angles breakage, then chainstay
at bridge cracks to later cast frame end failure. The designers got
after each problem in turn. Making one piece in a dynamic figure
ultra-rigid doesn't always solve problems and sometimes makes new ones.

It sounds as if the typical failures have gotten more benign over time? Am
I just reading that into what you wrote, or do you think that's actually
the case? Also, do you think failures have gotten more rare (as, say, a
percentage of all of the frames you sell)?

Quoted message said:

Jay Beattie said:

What was the deal with headlug/downtube joint? That seems like a
pretty benign joint. -- Jay Beattie.

Ideally, the joint is brazed tube-to-tube with the lug supporting that
joint. A straight-angled chop or two at the downtube can't mate
properly to the head tube.

"A Muzi" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

sergio said:

I have recorded differring opinions from two different, famous!,
framebuilders,
whose identity I shall provisionally withold, about the usefulness of
having a bridge just behind the bottom bracket housing in a steel
frame.

Opinion n.1
It must be there to make the frame stronger; plus, it is so cheap.

Opinion n.2
It should not be there (unless one wants to attach fenders to it). It
makes the frame prone to cracking around the area where the bridge is
attached, more so than it would be around the BB housing.

Any learned opinion from you, expert builders?

As a guy who replaces cracked chainstays regularly, it isn't all that
simple. After about 1977/1980, with cast BB shells, short chainstays
(which must be dented or ovalled more deeply), and thinner tubes, all of
which contribute, a pretty cast bridge can lead to chainstay cracks.
Those cast pieces are big (in terms of BTUs and braze time) then are
quite rigid and they often have squared sharp edges. A simple thin tube
is less likely to give any trouble.

Some builders such as 3Rensho used a small 'plate' extension behind the
BB, others added a 'rib' on the shell casting between the chainstays and
many builders simply skipped the thing entirely. All of those avoid
chainstay cracks pretty well.

Mounting mudguards on my fixie was harder without a chainstay bridge,
yes, but it was Jobst Brandt who pointed to the now-obvious problem of
tires wedging at wheel change. If you can live with that, leave it out.

I do not believe a closed figure (axle/QR, chainstays, BB shell) is
affected by that bridge or lack of it in any real sense of strength or
rigidity.

We can follow a history of breakage from the bikes of the early sixties
with fork blade/crown failures to the later lower headlug/downtube
cracks on until cast-BB-with-the-wrong angles breakage, then chainstay
at bridge cracks to later cast frame end failure. The designers got
after each problem in turn. Making one piece in a dynamic figure
ultra-rigid doesn't always solve problems and sometimes makes new ones.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

The melting point of many brazing alloys is very close to the temperature
where alloy steels can be permanently damaged from overheating. It's very
easy to quickly overheat thin wall tubing even when using silver brazing
alloys with lower melting temperatures.

A poorly mitered tube takes a lot more brazing material to fill the gaps
between the tubes. Most silver brazing alloys work best with a gap of
..001" to .003". Brass will fill a larger gap.

I've seen some chainstays crack at the BB joint but a lot more right side
chainstays that were cracked at 2" to 6" out from the BB. I only recall
seeing 1 or 2 cracked left side chainstays.

Also, an anecdotal observation: I've seen very few cracked Reynolds
chainstays. Most of the cracked ones were Columbus or Super Vitus tubing.
I asked several local frame builders about this and they agreed. Except
for breaks at the dropouts or BB they've seen very few cracked Reynolds
chainstays. Over the years Columbus decreased then increased the wall
thickness of the tubing in their SL chainstays .6mm - .7mm?

On frames with short chainstays the bridge may not be necessary and it may
just serve as a point to attach fenders. It seems logical that the bridge
would add some rigidity on frames with long chainstays. I heard once that
the bridge distributes some of the stresses at the BB joints.

Chas.

sergio said:

I have recorded differring opinions from two different, famous!,
framebuilders,
whose identity I shall provisionally withold, about the usefulness of
having a bridge just behind the bottom bracket housing in a steel
frame.

Opinion n.1
It must be there to make the frame stronger; plus, it is so cheap.

Opinion n.2
It should not be there (unless one wants to attach fenders to it). It
makes the frame prone to cracking around the area where the bridge is
attached, more so than it would be around the BB housing.

Any learned opinion from you, expert builders?

Sergio
Pisa

http://img2.freeimagehosting.net/uploads/389e0163dc.jpg

trek 700 commuter 1990?
broke last year and got it welded for $35 and still on the road.

futrino said:

trek 700 commuter 1990?
broke last year and got it welded for $35 and still on the road.

Well, If I see right how it had been inplanted, that must have been
the very worst bridge on the continent.

Sergio
Pisa

Quoted message said:

Quoted message said:

Quoted message said:

> sergio wrote:
>> I have recorded differring opinions from two different, famous!,
>> framebuilders,
>> whose identity I shall provisionally withold, about the usefulness of
>> having a bridge just behind the bottom bracket housing in a steel
>> frame.
>> Opinion n.1
>> It must be there to make the frame stronger; plus, it is so cheap.
>> Opinion n.2
>> It should not be there (unless one wants to attach fenders to it). It
>> makes the frame prone to cracking around the area where the bridge is
>> attached, more so than it would be around the BB housing.
>> Any learned opinion from you, expert builders?

Quoted message said:

Quoted message said:

Quoted message said:

A Muzi <[email hidden]> blathered:
> As a guy who replaces cracked chainstays regularly, it isn't all that
> simple. After about 1977/1980, with cast BB shells, short chainstays
> (which must be dented or ovalled more deeply), and thinner tubes, all of
> which contribute, a pretty cast bridge can lead to chainstay cracks.
> Those cast pieces are big (in terms of BTUs and braze time) then are
> quite rigid and they often have squared sharp edges. A simple thin tube
> is less likely to give any trouble.
> Some builders such as 3Rensho used a small 'plate' extension behind the
> BB, others added a 'rib' on the shell casting between the chainstays and
> many builders simply skipped the thing entirely. All of those avoid
> chainstay cracks pretty well.
> Mounting mudguards on my fixie was harder without a chainstay bridge,
> yes, but it was Jobst Brandt who pointed to the now-obvious problem of
> tires wedging at wheel change. If you can live with that, leave it out.
> I do not believe a closed figure (axle/QR, chainstays, BB shell) is
> affected by that bridge or lack of it in any real sense of strength or
> rigidity.
> We can follow a history of breakage from the bikes of the early sixties
> with fork blade/crown failures to the later lower headlug/downtube
> cracks on until cast-BB-with-the-wrong angles breakage, then chainstay
> at bridge cracks to later cast frame end failure. The designers got
> after each problem in turn. Making one piece in a dynamic figure
> ultra-rigid doesn't always solve problems and sometimes makes new ones.

Quoted message said:

Quoted message said:

Jay Beattie said:

What was the deal with headlug/downtube joint? That seems like a
pretty benign joint. -- Jay Beattie.

Quoted message said:

A Muzi said:

Ideally, the joint is brazed tube-to-tube with the lug supporting that
joint. A straight-angled chop or two at the downtube can't mate
properly to the head tube

Gary Young said:

It sounds as if the typical failures have gotten more benign over time? Am
I just reading that into what you wrote, or do you think that's actually
the case? Also, do you think failures have gotten more rare (as, say, a
percentage of all of the frames you sell)?

Yes, absolutely!
Surviving steel bike makers build, overall, a much higher quality
product in every way. Not only fewer 'stupid' errors but uniformly
better alignment, threading, finish, etc.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi said:

Quoted message said:

Quoted message said:

>> sergio wrote:
>>> I have recorded differring opinions from two different, famous!,
>>> framebuilders,
>>> whose identity I shall provisionally withold, about the usefulness of
>>> having a bridge just behind the bottom bracket housing in a steel
>>> frame.
>>> Opinion n.1
>>> It must be there to make the frame stronger; plus, it is so cheap.
>>> Opinion n.2
>>> It should not be there (unless one wants to attach fenders to it). It
>>> makes the frame prone to cracking around the area where the bridge is
>>> attached, more so than it would be around the BB housing.
>>> Any learned opinion from you, expert builders?
> A Muzi <[email hidden]> blathered:
>> As a guy who replaces cracked chainstays regularly, it isn't all that
>> simple. After about 1977/1980, with cast BB shells, short chainstays
>> (which must be dented or ovalled more deeply), and thinner tubes, all of
>> which contribute, a pretty cast bridge can lead to chainstay cracks.
>> Those cast pieces are big (in terms of BTUs and braze time) then are
>> quite rigid and they often have squared sharp edges. A simple thin tube
>> is less likely to give any trouble.
>> Some builders such as 3Rensho used a small 'plate' extension behind the
>> BB, others added a 'rib' on the shell casting between the chainstays and
>> many builders simply skipped the thing entirely. All of those avoid
>> chainstay cracks pretty well.
>> Mounting mudguards on my fixie was harder without a chainstay bridge,
>> yes, but it was Jobst Brandt who pointed to the now-obvious problem of
>> tires wedging at wheel change. If you can live with that, leave it out.
>> I do not believe a closed figure (axle/QR, chainstays, BB shell) is
>> affected by that bridge or lack of it in any real sense of strength or
>> rigidity.
>> We can follow a history of breakage from the bikes of the early sixties
>> with fork blade/crown failures to the later lower headlug/downtube
>> cracks on until cast-BB-with-the-wrong angles breakage, then chainstay
>> at bridge cracks to later cast frame end failure. The designers got
>> after each problem in turn. Making one piece in a dynamic figure
>> ultra-rigid doesn't always solve problems and sometimes makes new ones.
Jay Beattie wrote:
> What was the deal with headlug/downtube joint? That seems like a
> pretty benign joint. -- Jay Beattie.

A Muzi said:

Ideally, the joint is brazed tube-to-tube with the lug supporting that
joint. A straight-angled chop or two at the downtube can't mate
properly to the head tube

Gary Young said:

It sounds as if the typical failures have gotten more benign over time? Am
I just reading that into what you wrote, or do you think that's actually
the case? Also, do you think failures have gotten more rare (as, say, a
percentage of all of the frames you sell)?

Yes, absolutely!
Surviving steel bike makers build, overall, a much higher quality
product in every way. Not only fewer 'stupid' errors but uniformly
better alignment, threading, finish, etc.

Exactly how many surviving steel bike makers are there in the world?
Talking only about factory bike makers, not 1-2 man custom makers such
as Sachs, Kellogg, Wiegle, etc. I think Serotta and maybe Colnago and
Pinarello still offer a steel frame. Waterford of course makes steel
frames but has only been a business of its own for about 15 years.
Other steel makers such as Surly(QBP), Soma, Kogswell are all new
companies that owe much of their existence to the internet publicity.
Guerciotti, Ciocc, Tomassinni, Gios, Pegorretti, Mondonico, and a few
other Italian or companies with Italian names probably still make
steel frames but are hardly seen or sold in the US. They are pretty
much special order.

Quoted message said:

--
Andrew Muziwww.yellowjersey.org
Open every day since 1 April, 1971- Hide quoted text -

- Show quoted text -

Quoted message said:

sergio said:

I have recorded differring opinions from two different, famous!,
framebuilders,
whose identity I shall provisionally withold, about the usefulness of
having a bridge just behind the bottom bracket housing in a steel
frame.
Opinion n.1
It must be there to make the frame stronger; plus, it is so cheap.
Opinion n.2
It should not be there (unless one wants to attach fenders to it). It
makes the frame prone to cracking around the area where the bridge is
attached, more so than it would be around the BB housing.
Any learned opinion from you, expert builders?

futrino said:

http://img2.freeimagehosting.net/uploads/389e0163dc.jpg
trek 700 commuter 1990?
broke last year and got it welded for $35 and still on the road.

These may be a different failure from what Sergio asked about. This one
rusted through as it was not vented:
http://www.yellowjersey.org/photosfromthepast/NIMGADE.JPG
Was yours filled with brown water?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

Quoted message said:

Quoted message said:

>>> sergio wrote:
>>>> I have recorded differring opinions from two different, famous!,
>>>> framebuilders,
>>>> whose identity I shall provisionally withold, about the usefulness of
>>>> having a bridge just behind the bottom bracket housing in a steel
>>>> frame.
>>>> Opinion n.1
>>>> It must be there to make the frame stronger; plus, it is so cheap.
>>>> Opinion n.2
>>>> It should not be there (unless one wants to attach fenders to it). It
>>>> makes the frame prone to cracking around the area where the bridge is
>>>> attached, more so than it would be around the BB housing.
>>>> Any learned opinion from you, expert builders?
>> A Muzi <[email hidden]> blathered:
>>> As a guy who replaces cracked chainstays regularly, it isn't all that
>>> simple. After about 1977/1980, with cast BB shells, short chainstays
>>> (which must be dented or ovalled more deeply), and thinner tubes, all of
>>> which contribute, a pretty cast bridge can lead to chainstay cracks.
>>> Those cast pieces are big (in terms of BTUs and braze time) then are
>>> quite rigid and they often have squared sharp edges. A simple thin tube
>>> is less likely to give any trouble.
>>> Some builders such as 3Rensho used a small 'plate' extension behind the
>>> BB, others added a 'rib' on the shell casting between the chainstays and
>>> many builders simply skipped the thing entirely. All of those avoid
>>> chainstay cracks pretty well.
>>> Mounting mudguards on my fixie was harder without a chainstay bridge,
>>> yes, but it was Jobst Brandt who pointed to the now-obvious problem of
>>> tires wedging at wheel change. If you can live with that, leave it out.
>>> I do not believe a closed figure (axle/QR, chainstays, BB shell) is
>>> affected by that bridge or lack of it in any real sense of strength or
>>> rigidity.
>>> We can follow a history of breakage from the bikes of the early sixties
>>> with fork blade/crown failures to the later lower headlug/downtube
>>> cracks on until cast-BB-with-the-wrong angles breakage, then chainstay
>>> at bridge cracks to later cast frame end failure. The designers got
>>> after each problem in turn. Making one piece in a dynamic figure
>>> ultra-rigid doesn't always solve problems and sometimes makes new ones.

Quoted message said:

Quoted message said:

Quoted message said:

> Jay Beattie wrote:
>> What was the deal with headlug/downtube joint? That seems like a
>> pretty benign joint. -- Jay Beattie.

Quoted message said:

Quoted message said:

Quoted message said:

A Muzi wrote:
> Ideally, the joint is brazed tube-to-tube with the lug supporting that
> joint. A straight-angled chop or two at the downtube can't mate
> properly to the head tube

Quoted message said:

Quoted message said:

Gary Young said:

It sounds as if the typical failures have gotten more benign over time? Am
I just reading that into what you wrote, or do you think that's actually
the case? Also, do you think failures have gotten more rare (as, say, a
percentage of all of the frames you sell)?

Quoted message said:

A Muzi said:

Yes, absolutely!
Surviving steel bike makers build, overall, a much higher quality
product in every way. Not only fewer 'stupid' errors but uniformly
better alignment, threading, finish, etc.

Quoted message said:

Exactly how many surviving steel bike makers are there in the world?
Talking only about factory bike makers, not 1-2 man custom makers such
as Sachs, Kellogg, Wiegle, etc. I think Serotta and maybe Colnago and
Pinarello still offer a steel frame. Waterford of course makes steel
frames but has only been a business of its own for about 15 years.
Other steel makers such as Surly(QBP), Soma, Kogswell are all new
companies that owe much of their existence to the internet publicity.
Guerciotti, Ciocc, Tomassinni, Gios, Pegorretti, Mondonico, and a few
other Italian or companies with Italian names probably still make
steel frames but are hardly seen or sold in the US. They are pretty
much special order.

I have no idea how many. Lots more than 'special order'!!
You left out the wonderful Hodaka as well as Panasonic, Brigestone and
all the Keirin builders. British; Jackson-Hetchins, Thorne, Mercian come
to mind.
And what about the Dutch builders (Batavus, Gizelle, etc) ?
Bianchi/Milano still makes volume steel bikes for their market, just not
for ours. (Bianchi/Bergamo doesn't do steel now) And Bianchi/Santiago
Chile, probably another couple dozen operations like that (Cspel, Steyr
etc).
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

futrino said:

trek 700 commuter 1990?
broke last year and got it welded for $35 and still on the road.

Back when I did warranty inspection for Trek, that would have won you a
new frame.

--

John ([email hidden])

A Muzi said:

And what about the Dutch builders (Batavus, Gazelle, etc) ?

There are some smaller factories still building steel frames, but AFAIK
all the big ones have sold of the frame building lines and outsourced to
the (far) east. Most 45 pound roadsters now feature 'lightweight'
aluminium frames
--
/Marten

info(apestaartje)m-gineering(punt)nl

Jay Beattie said:

What was the deal with headlug/downtube joint? That seems like a
pretty benign joint. -- Jay Beattie.

That's just about the highest stresspoint on the bike. The downtube
is by far the most-stressed main tube, since both seat tube and top
tube are under compression ~ the downtube alone is suffering enormous
pulling forces. If there is one tube you should not add braze-ons to,
it's the downtube. Many times, braze-on gear levers or even bottle
mounts lead to cracking and tearing and self-destruction of the downtube.

Look at any modern aluminum bike. there's a good reason why the
downtube looks 2x beefier than any other tube.

- Don Gillies
San Diego, CA

Quoted post said:

Exactly how many surviving steel bike makers are there in the world?
Talking only about factory bike makers, not 1-2 man custom makers such
as Sachs, Kellogg, Wiegle, etc. I think Serotta and maybe Colnago and
Pinarello still offer a steel frame. Waterford of course makes steel
frames but has only been a business of its own for about 15 years.

One could argue that Waterford is the oldest of all steel bike
makers. Mercian probably comes in second place, or maybe tied with
Dawes ?? Doesn't Dawes still manufacture steel frames ??

- Don Gillies
San Diego, CA

On 29 Sep 2007 01:08:46 -0700, [email hidden] (Donald Gillies)

Quoted message said:

Jay Beattie said:

What was the deal with headlug/downtube joint? That seems like a
pretty benign joint. -- Jay Beattie.

That's just about the highest stresspoint on the bike. The downtube
is by far the most-stressed main tube, since both seat tube and top
tube are under compression ~ the downtube alone is suffering enormous
pulling forces. If there is one tube you should not add braze-ons to,
it's the downtube. Many times, braze-on gear levers or even bottle
mounts lead to cracking and tearing and self-destruction of the downtube.

Look at any modern aluminum bike. there's a good reason why the
downtube looks 2x beefier than any other tube.

Yes, and it's nothing to do with the tensile load, which can be (and
has been, on some designs) resisted by a suitable sized wire. The very
large diameter down tube is there to resist torsional loads.

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

Kinky Cowboy said:

Yes, and it's nothing to do with the tensile load, which can be (and
has been, on some designs) resisted by a suitable sized wire.

About tension, and tensile stregth that is needed down there, I have a
question.

What wire would be adequate?
How about a brake cord?

I ask since I repaired, and put back into service, a Colnago Carbitubo
that had unglued at the joint by adding a bike brake cord. The cord
did elongate to the point that I was forced to tension it again; and
this time I improved the fix by implanting a couple of splines
(english?) through the tubes.

To be honest, I was rather surprised that a brake cord would elongate
that much, and probably it would have kept getting longer and longer.

Sergio
Pisa