Why did top BB shift cable guides disappear?

Using maximum security, Booker C. Bense asked:

Quoted message said:

_ On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing. Is there some obvious
reason other than the cost of brazing on the guides as to
why frame makers no longer use this style of cable
routing?

Cost is a BIGGIE, but not the only reason.

This is actually something that developed in the mountain
bike realm for technical reasons, then was applie to
everything when it turned out to be cheaper.

Early mountain bikes commonly had problems with clearance
between the bottom of the front derailer cage and the rear
shift cable.

Mountain bikes use wide range front derailers, and
comparatively small chainrings, which conspired to move the
front derailer downwards.

I distinctly recall tearing my hair out trying to get some
older Mongeese to shift well, when I couldn't mount the
front derailer low enough for good shifting without causing
the cage to hang up on the rear shift cable.

As it turns out, drilling and tapping a hole in the bottom
of the BB shell is a LOT cheaper than brazing guides onto
the top of the shell.

Another benefit of the lower routing is that it makes the
bottom bracket are of the frame much easier to clean.

Sheldon "Now You Know Why I'm Bald" Brown +--------------------------------------------------
+
| Whoever you vote for, the government gets in. | John Jones--
| Oysterband |
+--------------------------------------------------+ Harris
Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX
617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗
sheldonbrown.comsheldonbrown.comOpen ↗

<[email hidden]> a écrit dans
le message de :
"]news:[email hidden]...

Quoted message said:

-----BEGIN PGP SIGNED MESSAGE-----

_ On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing. Is there some obvious
reason other than the cost of brazing on the guides as to
why frame makers no longer use this style of cable
routing?

_ Booker C. Bense

I don't know about too many models, but the 1996 Kestrel I
have has the guides fixed above the BB shell. Clean cables,
that way, I think
--
Bonne route,

Sandy Paris FR

On Tue, 18 May 2004 11:28:44 -0400, Sheldon Brown

may have said:

Sheldon "Now You Know Why I'm Bald" Brown

Geez, and here I thought that shiny, grooved surface on the
top of your head was a helmet. I didn't realize you were
part Klingon. Ya live and learn.

--
My email address is antispammed; pull WEEDS if replying via
e-mail. Typoes are not a bug, they're a feature. Words
processed in a facility that contains nuts.

Sheldon Brown:

Quoted message said:

Another benefit of the lower routing is that it makes the
bottom bracket are of the frame much easier to clean.

Is there any practical reason why gear cables shouldn't have
outer cabling along their full length like brake cables?

d.

davek asked:

Quoted message said:

Is there any practical reason why gear cables
shouldn't have outer cabling along their full length
like brake cables?

Only an issue of weight and aesthetics. Probably a good way
to go for bikes to be ridden in unusually mucky conditions.

That setup used to be associated with bottom of the barrel
department store bikes.

Back in the days before lined housing and die-drawn cables,
this would have led to more cable friction, but that's no
longer an issue with modern parts.

Sheldon "Full House" Brown +--------------------------------------------
+
| Life is what happens to you, | while you're busy making
| other plans. | --John Lennon |
+--------------------------------------------+ Harris
Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX
617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗
sheldonbrown.comsheldonbrown.comOpen ↗

davek asked:

Quoted message said:

Is there any practical reason why gear cables
shouldn't have outer cabling along their full length
like brake cables?

Only an issue of weight and aesthetics. Probably a good way
to go for bikes to be ridden in unusually mucky conditions.

That setup used to be associated with bottom of the barrel
department store bikes.

Back in the days before lined housing and die-drawn cables,
this would have led to more cable friction, but that's no
longer an issue with modern parts.

Sheldon "Full House" Brown +--------------------------------------------
+
| Life is what happens to you, | while you're busy making
| other plans. | --John Lennon |
+--------------------------------------------+ Harris
Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX
617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗
sheldonbrown.comsheldonbrown.comOpen ↗

<[email hidden].-
edu> wrote in >

Quoted message said:

On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing.

What is better about this?

JT

Quoted message said:

-----BEGIN PGP SIGNED MESSAGE-----

_ On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing. Is there some obvious
reason other than the cost of brazing on the guides as to
why frame makers no longer use this style of cable
routing?

Slightly tighter bend in the cable run?

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

Quoted message said:

-----BEGIN PGP SIGNED MESSAGE-----

_ On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing. Is there some obvious
reason other than the cost of brazing on the guides as to
why frame makers no longer use this style of cable
routing?

_ Booker C. Bense

It's cheaper to drill a hole in the BB and bolt on a guide
than to braze on a couple guides in a place where a lot of
brazing/welding has already occured.

Rule of thumb: any question starting with "Why?" can usually
be answered "Money."

Jeff

Quoted post said:

Originally posted by Jeff Wills
<[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

-----BEGIN PGP SIGNED MESSAGE-----

_ On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing. Is there some obvious
reason other than the cost of brazing on the guides as to
why frame makers no longer use this style of cable
routing?

_ Booker C. Bense

It's cheaper to drill a hole in the BB and bolt on a guide
than to braze on a couple guides in a place where a lot of
brazing/welding has already occured.

Rule of thumb: any question starting with "Why?" can usually
be answered "Money."

Jeff

I had an old Pugeot with the braze ons on top of the BB and it required a short section of housing for the cable. The housing was situated in such a way that gunk would accumulate at the end and cause sticktion problems on downshifts.

I also have a bike with the braze ons (not a bolt-on guide) underneath the BB, quite elegant. I'd heard that with aluminum frames the cable could saw a slot in the tubing so bolt-on guides that kept the cable off the frame became the standard.

Quoted message said:

_ On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing. Is there some obvious
reason other than the cost of brazing on the guides as to
why frame makers no longer use this style of cable
routing?

_ Booker C. Bense

New style looks nicer, IMHO, especially on my single-speed,
which has the guide you mention, just hanging out there with
no cable in them. It's not worth springing for a paint job
to grind it off..

On a different matter, Booker - everytime you post, the
entire display in Google groups goes wacky because your
name displays as 61 characters long - can you change some
settings so that you don't drive thousands of readers
crazy? Thanks.

Quoted message said:

_ On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing. Is there some obvious
reason other than the cost of brazing on the guides as to
why frame makers no longer use this style of cable
routing?

_ Booker C. Bense

New style looks nicer, IMHO, especially on my single-speed,
which has the guide you mention, just hanging out there with
no cable in them. It's not worth springing for a paint job
to grind it off..

On a different matter, Booker - everytime you post, the
entire display in Google groups goes wacky because your
name displays as 61 characters long - can you change some
settings so that you don't drive thousands of readers
crazy? Thanks.

DiabloScott said:

I had an old Pugeot with the braze ons on top of the BB
and it required a short section of housing for the cable.
The housing was situated in such a way that gunk would
accumulate at the end and cause sticktion problems on
downshifts.

The housing would also fill with water, which froze in
winter. I once had an old Huret rear mech freeze such that
it wouldn't shift to a smaller sprocket (doing a paper round
at 6am in the snow). We had proper winters in those days!

More recently I had a water bottle freeze solid when the
bike was left outside a cafe for 45 minutes. It was so cold
that I didn't miss being able to drink!

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

Quoted message said:

-----BEGIN PGP SIGNED MESSAGE-----

_ On my 70's vintage bike frame there are brazed on guides
for the shift cables on the top of the bottom bracket.
This to me seems like a much better solution than the
current below the BB cable routing. Is there some obvious
reason other than the cost of brazing on the guides as to
why frame makers no longer use this style of cable
routing?

_ Booker C. Bense

From Sheldon Brown

sheldonbrown.comgloss ca m.htmlOpen ↗

"The below-the-bottom-bracket option has the advantage of
being cheaper, and, for some bikes with very small
chainweels, it eliminates interference betwixt the rear
derailer cable and the bottom of the front derailer cage. It
also makes it slightly easier to clean the frame
cosmetically.

The above-the-bottom-bracket system is superior in that the
cable is shorter and the loop of housing at the rear
derailer is not as tight, since the cable stop is atop the
chainstay, rather than beneath it.

Poor lubrication of bottom-bracket cable guides is a common
cause of autoshifting. Some bicycles use a cable guide on
one side of the seat cluster for a rear cantilever brake
cable, rather than use a short length of housing between two
housing stops."

Bill Putnam

Werehatrack said:

On Tue, 18 May 2004 11:28:44 -0400, Sheldon Brown

may have said:

Sheldon "Now You Know Why I'm Bald" Brown

Geez, and here I thought that shiny, grooved surface on the
top of your head was a helmet. I didn't realize you were
part Klingon. Ya live and learn.

He's not bald. His head is a slick for better traction.

High pressure, Sheldon?
--
Rick Onanian

Sheldon Brown said:

davek asked:

Quoted message said:

Is there any practical reason why gear cables shouldn't
have outer cabling along their full length like brake
cables?

Only an issue of weight and aesthetics. Probably a good
way to go for bikes to be ridden in unusually mucky
conditions.

That setup used to be associated with bottom of the barrel
department store bikes.

Back in the days before lined housing and die-drawn
cables, this would have led to more cable friction, but
that's no longer an issue with modern parts.

Sheldon "Full House" Brown +--------------------------------------------
+
| Life is what happens to you, | while you're busy
| making other plans. | --John Lennon |
+--------------------------------------------+ Harris
Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX
617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗
sheldonbrown.comsheldonbrown.comOpen ↗

Sheldon, this very afternoon I asked a related question at
my LBS and got what I think is a screwy answer. I just fell
heir to a 1970-vintage Japanese Schwinn 27" 10-speed road
bike and want to replace the (factory original!) cables
with modern ones, but the rear brake and both der. cables
are the cable-stop or braze-on type ..... which I think is
a stupid design. I asked the LBS to recommend a nice way to
attach fully housed cables to the frame .... and got no
help. They say it's just not done; most bikes have braze-
ons; everyone who puts any mileage on a bike replaces
cables about every two years anyway, so there's nothing to
be gained by trying to keep water and grit out of cable
housings. So is there no good, clean, EASY way to attach
fully housed cables to a frame?

Michael

In article <[email hidden]>,

davek said:

Sheldon Brown:

Quoted message said:

Another benefit of the lower routing is that it makes the
bottom bracket are of the frame much easier to clean.

Is there any practical reason why gear cables
shouldn't have outer cabling along their full length
like brake cables?

Friction? The derailer return spring has to overcome the
friction in the cable to return the derailer to the
proper position. Most shifters aren't designed for the
kind of mechanical advantage a brake lever is, or the for
the kind of force. Put an extra-strong spring in the
derailer, and you'll get sore thumbs or wrists and (more)
broken STI levers.

Michael said:

So is there no good, clean, EASY way to attach fully housed
cables to a frame?

Zip ties.
--
Rick Onanian