Why the holes in old BB shells?

Matt O'Toole said:

I never understood why older racing frames have big holes in their
BB shells. Is this to drain water, to allow flushing and
re-greasing without disassembly, or just to look cute, with heart
shaped holes and such?

Quoted message said:

This always seemed stupid to me, because of road spray, etc.

I recall that the keyhole slot in the seat tube was deeper than the
clamping depth for the seat post and that spray from the rear wheel
could enter to fill the bottom of the frame with water. To avoid
this, we made sure there was liberal grease in that slot.

Then someone started drilling a hole in the center of the BB to let
the water out, after which the idea was widely imitated. Various
logos were cut to make even larger openings, so much so that the shell
had no lateral strength and developed nonparallel faces in use.

Yes, I found that to be stupid because it did not address the problem
of allowing water to enter, aside from being an inexcusable structural
weak spot.

Jobst Brandt

[email hidden] explained :

Quoted message said:

Matt O'Toole said:

I never understood why older racing frames have big holes in their
BB shells. Is this to drain water, to allow flushing and
re-greasing without disassembly, or just to look cute, with heart
shaped holes and such?

Quoted message said:

This always seemed stupid to me, because of road spray, etc.

I recall that the keyhole slot in the seat tube was deeper than the
clamping depth for the seat post and that spray from the rear wheel
could enter to fill the bottom of the frame with water. To avoid
this, we made sure there was liberal grease in that slot.

Then someone started drilling a hole in the center of the BB to let
the water out, after which the idea was widely imitated. Various
logos were cut to make even larger openings, so much so that the shell
had no lateral strength and developed nonparallel faces in use.

Yes, I found that to be stupid because it did not address the problem
of allowing water to enter, aside from being an inexcusable structural
weak spot.

Jobst Brandt

I think you can never fulle avoid water entering the frame.

Is it through the seatpost or other likely routes as the steerer tube
or the bracket itself.

What comes in must go out!

Wherefore else holes in the fork tube ends (4x)?

Martin

either BB Borers
or an advanced thought condensation eliminator

In article <[email hidden]>,

Martin Borsje said:

What comes in must go out!

Wherefore else holes in the fork tube ends (4x)?

Venting to allow hot air out of the tube when brazing, which would
otherwise force itself out through the joint causing spattering of
molten brass or silver. It's not necessary when the tube is open on the
ends, which is the case in the main frame tubes. The vent holes should
be closed by the framebuilder at the end of brazing, as they serve no
purpose after the frame is built. Indeed, they are a water infiltration
point.

Tim McNamara said:

In article <[email hidden]>,

Martin Borsje said:

What comes in must go out!

Wherefore else holes in the fork tube ends (4x)?

Venting to allow hot air out of the tube when brazing, which would
otherwise force itself out through the joint causing spattering of
molten brass or silver. It's not necessary when the tube is open on the
ends, which is the case in the main frame tubes. The vent holes should
be closed by the framebuilder at the end of brazing, as they serve no
purpose after the frame is built. Indeed, they are a water infiltration
point.

Why not keep the bottom bracket totally sealed and vent the seat tube
externally to drain accumulated moisture?? (other than the problem of
keeping the weeping hole from plugging up??)

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

Matt O'Toole said:

I never understood why older racing frames have big holes in their BB
shells. Is this to drain water, to allow flushing and re-greasing without
disassembly, or just to look cute, with heart shaped holes and such?

This always seemed stupid to me, because of road spray, etc.

Remember the 3 Stooges? There was a standard gag they had with Curly in
a boat that was half full of water, and he drilled holes in the bottom
to let the water out. This is similar.

--

David L. Johnson

Let's not escape into mathematics. Let's stay with reality.
-- Michael Crichton

Martin Borsje said:

What comes in must go out!

Wherefore else holes in the fork tube ends (4x)?

Those holes have nothing to do with water. If you tried to weld or
braze a tube at both ends, the air inside would expand as you worked,
and would push out the brazing or welding you were doing. Those holes
provide pressure relief so that the brazing or welding would hold.

--

David L. Johnson

Let's not escape into mathematics. Let's stay with reality.
-- Michael Crichton

getting into the xams cheer early ?

David L. Johnson said:

Martin Borsje said:

What comes in must go out!

Wherefore else holes in the fork tube ends (4x)?

Quoted message said:

Those holes have nothing to do with water. If you tried to weld or
braze a tube at both ends, the air inside would expand as you worked,
and would push out the brazing or welding you were doing. Those holes
provide pressure relief so that the brazing or welding would hold.

And to allow the builder to rinse out flux from inside the tubes prior
to painting.

--

John ([email hidden])

David L. Johnson said:

Martin Borsje said:

What comes in must go out!

Wherefore else holes in the fork tube ends (4x)?

Those holes have nothing to do with water. If you tried to weld or
braze a tube at both ends, the air inside would expand as you worked,
and would push out the brazing or welding you were doing. Those holes
provide pressure relief so that the brazing or welding would hold.

For air a single hole would be enough, but if you want to get water out
you'll need a vent.
Water will always find it's way in, for instance through condensation.
You either have to insure that the tube is 100% sealed or vent it to the
atmosphere. As frames with drainholes last long enough, i don't think it
is worth the bother and the risk to seal the few tubes which lend
themselves to sealing.

--
/Marten

info(apestaartje)m-gineering(punt)nl

Quoted message said:

Matt O'Toole writes:

Quoted message said:

Quoted message said:

I never understood why older racing frames have big holes in their
BB shells. Is this to drain water, to allow flushing and
re-greasing without disassembly, or just to look cute, with heart
shaped holes and such?

This is only done on older racing bikes. Only on top-of-the-line
racing bikes. In most cases, top-end racing bikes are not raced in
the rain. This is done to save weight and add prestige, period.

- Don Gillies
San Diego, CA

(Donald Gillies) said:

Quoted message said:

Matt O'Toole said:

I never understood why older racing frames have big holes in their
BB shells. Is this to drain water, to allow flushing and
re-greasing without disassembly, or just to look cute, with heart
shaped holes and such?

This is only done on older racing bikes. Only on top-of-the-line
racing bikes. In most cases, top-end racing bikes are not raced in
the rain.

The major pro races are (or were) suspended or postponed due to
rain!?!

Quoted message said:

This is done to save weight

How much weight do you think this saves?

Quoted message said:

and add prestige, period.

Bingo!!!!

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

Quoted message said:

Unfortunately, pictures of the underside of the bottom
bracket shell are as rare as photos peeking up the
hairy nostrils of Playboy models.

Touch-up king Ray Dobbins doesn't shrink from photographing his models'
undersides:

http://www.raydobbins.com/bianchi/photos/photo31.html

http://www.raydobbins.com/supernew/photos/photo52.html

http://www.raydobbins.com/mexicooro/photos/photo39.html

http://www.raydobbins.com/colnagochrome/photos/photo22.html

http://www.raydobbins.com/masibb/photos/photo1.html

http://www.raydobbins.com/molteni_replica/molteni_replica.htm

James Thomson

http://jacob.leverich.org/pix/2005.08.18-moyer_cycles_3/medium/IMG_1748.JPG

http://www.campyonly.com/images/mystuff/2006/raysport/DSCN0199_800.jpg

http://www.firstflightbikes.com/_borders/WeigleBB.JPG

http://www.asahi-net.or.jp/~uc6y-ssk/Image/classicroad/kimkaz_masi04_m.jpg

http://www.bikecult.com/works/archive/03bicycles/vorontsovRFbb.jpg

http://www.cyclesdeoro.com/images/Interbike%20Shows/Interbike%202005/Thursday/PICT2994.JPG

http://www.littlefishbicycles.com/fixed_wheel_pics/frame_cleaned_bb.jpg

James Thomson said:

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

Quoted message said:

Unfortunately, pictures of the underside of the bottom
bracket shell are as rare as photos peeking up the
hairy nostrils of Playboy models.

Touch-up king Ray Dobbins doesn't shrink from photographing his models'
undersides:

http://www.raydobbins.com/bianchi/photos/photo31.html

http://www.raydobbins.com/supernew/photos/photo52.html

http://www.raydobbins.com/mexicooro/photos/photo39.html

http://www.raydobbins.com/colnagochrome/photos/photo22.html

http://www.raydobbins.com/masibb/photos/photo1.html

http://www.raydobbins.com/molteni_replica/molteni_replica.htm

James Thomson

http://jacob.leverich.org/pix/2005.08.18-moyer_cycles_3/medium/IMG_1748.JPG

http://www.campyonly.com/images/mystuff/2006/raysport/DSCN0199_800.jpg

http://www.firstflightbikes.com/_borders/WeigleBB.JPG

http://www.asahi-net.or.jp/~uc6y-ssk/Image/classicroad/kimkaz_masi04_m.jpg

http://www.bikecult.com/works/archive/03bicycles/vorontsovRFbb.jpg

http://www.cyclesdeoro.com/images/Interbike%20Shows/Interbike%202005/Thursday/PICT2994.JPG

http://www.littlefishbicycles.com/fixed_wheel_pics/frame_cleaned_bb.jpg

Dear James,

Nice pictures.

Alas, I didn't make myself clear. I was looking for old bicycles, by
which I mean pre-1910 and preferably pre-1900 safeties, not newfangled
stuff.

That is, I'm curious about when the drain holes started more than the
artistic carving.

As far as I can tell, the older bottom-bracket pieces didn't come with
drain holes. Instead, they came with a pair of threaded holes on top
of the bottom bracket shell for adding oil-fittings to lubricate the
bearings:

http://books.google.com/books?id=4EsxXM90hDcC&printsec=frontcover&dq=Cycle+Building+and+Repairing&as_brr=1&ei=GrUuR6qDGYb0oAKS6oH2CQ#PPA50,M1

See the bottom of page 49 and the drawing that follows on page 50.

Here's the only faintly applicable ~1900 comment that I've found so
far, which suggests that they were more worried about oil dripping
from the bottom bracket into the frame than water from the frame
getting into the bottom bracket:

"In some cases the cups [of the bottom bracket] instead of being
screwed into the bracket itself are screwed into a separate sleeve,
which, in its turn, fits into the bracket. This prevents the oil from
getting into the tubes of the frame, when the machine is turned upside
down to repair a puncture, and it also prevents the balls from going
astray in a similar way when putting the bearing together. This is a
little refinement no doubt, though corks put into the tube ends do
nearly as well."

http://books.google.com/books?id=NMgeFMDBE18C&pg=PA96&lpg=PA96&dq=%22getting+into+the+tubes+of+the+frame%22&source=web&ots=bcwgd0p0bO&sig=pHkjZ0pwApDIufB2yzXE1fDzqx4

I can never resist passages that involve turning bicycles upside down
for convenient maintenance.

Cheers,

Carl Fogel

Quoted message said:

Then someone started drilling a hole in the center of the BB to let
the water out, after which the idea was widely imitated.

How about holes on the dropout end of the chain stay? My Lemond
carbon frame has an open hole at the end of the drive side
stay where the dropout attaches, and I've noticed holes in other
chainstays.
The water will of course drain right down to the BB, and the hole is
big
enough to let crud accumulate on the interior of the stay.

Near as I can figure it's a manufacturing artifact. I'm thinking about
plugging it up with something.

Ernst Blofeld said:

Quoted message said:

Then someone started drilling a hole in the center of the BB to let
the water out, after which the idea was widely imitated.

Quoted message said:

How about holes on the dropout end of the chain stay? My Lemond
carbon frame has an open hole at the end of the drive side stay
where the dropout attaches, and I've noticed holes in other
chainstays. The water will of course drain right down to the BB,
and the hole is big enough to let crud accumulate on the interior of
the stay.

Quoted message said:

Near as I can figure it's a manufacturing artifact. I'm thinking
about plugging it up with something.

You haven't been following this thread well enough to have read what
the purpose of these holes is. The 1mm holes are for venting
expanding air when the part is brazed. Fork blades, seatstays, and
some chainstays are not open at either end when being brazed.

Jobst Brandt

Quoted message said:

Ernst Blofeld said:

Quoted message said:

Then someone started drilling a hole in the center of the BB to let
the water out, after which the idea was widely imitated.

How about holes on the dropout end of the chain stay? My Lemond
carbon frame has an open hole at the end of the drive side stay
where the dropout attaches, and I've noticed holes in other
chainstays. The water will of course drain right down to the BB,
and the hole is big enough to let crud accumulate on the interior of
the stay.
Near as I can figure it's a manufacturing artifact. I'm thinking
about plugging it up with something.

You haven't been following this thread well enough to have read what
the purpose of these holes is. The 1mm holes are for venting
expanding air when the part is brazed. Fork blades, seatstays, and
some chainstays are not open at either end when being brazed.

Jobst Brandt

The person you replied to indicated he has a vent hole in the end of
his LeMond CARBON chainstays. Does a carbon tube also need vent
holes? I think he is correct in that the vent holes in his carbon
chainstays are manufacturing artifacts.

Russell Seaton said:

Quoted message said:

Quoted message said:

> Then someone started drilling a hole in the center of the BB to let
> the water out, after which the idea was widely imitated.

Quoted message said:

Quoted message said:

Quoted message said:

How about holes on the dropout end of the chain stay? My Lemond
carbon frame has an open hole at the end of the drive side stay
where the dropout attaches, and I've noticed holes in other
chainstays. The water will of course drain right down to the BB,
and the hole is big enough to let crud accumulate on the interior of
the stay.

Quoted message said:

Quoted message said:

Quoted message said:

Near as I can figure it's a manufacturing artifact. I'm thinking
about plugging it up with something.

Quoted message said:

Quoted message said:

You haven't been following this thread well enough to have read
what the purpose of these holes is. The 1mm holes are for venting
expanding air when the part is brazed. Fork blades, seatstays, and
some chainstays are not open at either end when being brazed.

Quoted message said:

The person you replied to indicated he has a vent hole in the end of
his LeMond CARBON chainstays. Does a carbon tube also need vent
holes? I think he is correct in that the vent holes in his carbon
chainstays are manufacturing artifacts.

I think the adhesives have the same problem of out-gassing and would
compromise the joint if the temperature during curing changed or even
stayed the same. I wouldn't rely on a closed volume not changing gas
pressure.

Jobst Brandt

Water drainage. And yes, they can let water in as easily as out and if
their too big, will weaken the shell.

A small hole or two won't kill anything. If you're worried about water
splash getting your spindle wet, get a plastic sleeve and slide it in
between the cups.

- -
Compliments of:
"Your Friendly Neighborhood Wheelman"

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