recurrent looseness in bottom bracket

[Guy Tedesco]

i have to keep readjusting my bottom bracket as it keeps getting loose. it is not a cartridge bottom
bracket. it is a standard bearing set-up with ball bearings in retainer rings. is there a reason why
an adjustment keeps needing to be done. i torque to 50 foot-pounds both the fixed cup and lockring
as reccommended in zinn's maintenance-repair book.-guy from long island

 

[Jeff Martin]

Use some blue Locktite. First clean off the threads of the cups and the inner threads of the BB.
"guy tedesco" <[email protected]> wrote in message
news:[email protected]...
> i have to keep readjusting my bottom bracket as it keeps getting loose. it is not a cartridge
> bottom bracket. it is a standard bearing set-up with ball bearings in retainer rings. is there a
> reason why an adjustment keeps needing to be done. i torque to 50 foot-pounds both the fixed cup
> and lockring as reccommended in zinn's maintenance-repair book.-guy from long island

 

[Qui Si Parla Ca]

acorn-<< i have to keep readjusting my bottom bracket as it keeps getting loose. it is not a
cartridge bottom bracket. it is a standard bearing set-up with ball bearings in retainer rings. is
there a reason why an adjustment keeps needing to be done .

I say have the BB shell prepped, that is faced to make the two surfaces parallel....

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

 

[Qui Si Parla Ca]

DON'T use loctite....I have had to cut more than a few BBs outta framesets that were not lubed
properly. Face the BB shell, grease the BB shell, install correctly...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

 

[A Muzi]

"guy tedesco" <[email protected]> wrote in message
news:[email protected]...
> i have to keep readjusting my bottom bracket as it keeps getting loose. it is not a cartridge
> bottom bracket. it is a standard bearing set-up with ball bearings in retainer rings. is there a
> reason why an adjustment keeps needing to be done. i torque to 50 foot-pounds both the fixed cup
> and lockring as reccommended in zinn's maintenance-repair book.-guy from long island

When you have the opportunity, open the BB, ensure the right side cup is tight in the frame (
difficult at home, simple at a competent LBS with the proper tool) and look for wear.

What you describe (chronic loosening ) is consistent with a badly damaged bearing surface on the
down side of fatal wear. Might just be a loose right cup, though.

If you can reuse it, clean thoroughly and use plenty of fresh grease with the new beraings. If you
replace it, even moreso, use plenty of grease. Remember to adjust to a slight preload as a loose or
insufficiently preloaded BB will wear unevenly and quickly.

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

 

[David L. Johnso]

On Wed, 28 May 2003 13:16:16 +0000, Qui si parla Campagnolo wrote:

> DON'T use loctite....I have had to cut more than a few BBs outta framesets that were not lubed
> properly. Face the BB shell, grease the BB shell, install correctly...

As usual, Peter is right. One thing. Is the bike old? Is it Italian? If yes to both, then it could
very well be the standard design flaw of the species. The right cup on English-thread (now ISO)
bottom-brackets is left hand to deal with bearing precession that would tend to loosen the cup.
Italian threaded bikes (no longer done this way) had both cups right-hand thread, and the right cup
could loosen.

An easy way to check is to measure the width of the bb shell. English standard is/was 68mm,
Italian was 70.
--

David L. Johnson

__o | A foolish consistency is the hobgoblin of little minds, adored _`\(,_ | by little statesmen
and philosophers and divines. --Ralph Waldo (_)/ (_) | Emerson

 

[Harris]

David L. Johnson <[email protected]> wrote:
> Italian threaded bikes (no longer done this way) had both cups right-hand thread, and the right
> cup could loosen.

Is that right? Italian BBs now have left hand thread on the right? When did that change?

Art Harris

 

[Jasper Janssen]

On 29 May 2003 12:55:10 GMT, [email protected] (Qui si parla Campagnolo) wrote:

>Italian works fine if the BB is installed correctly, on a prepped frameset. English threading was
>an answer to **** poor wrenching. Changing a design to make something cheaper, easier, not likely
>to get gooned up, is not uncommon(radial laced front wheels for example).

Yeah but.. yeah but.. a radial laced spoke is at least 3 % shorter, and thus lighter! On a full bike
which has 4 wheels at 48 spokes each, this can easily save you 10 grams!

Aaaaaaanyway.

Which forces unscrew cups, anyway? it's not friction in the bearing itself, I think -- to take the
extreme case, if a bearing seized you'd be *un*threading the cups by pedaling in the normal
direction, unless I'm flipping something over in my mind.

Jasper

 

[Tom Ace]

Jasper Janssen wrote:

> Which forces unscrew cups, anyway? it's not friction in the bearing itself, I think -- to take the
> extreme case, if a bearing seized you'd be *un*threading the cups by pedaling in the normal
> direction, unless I'm flipping something over in my mind.

Precession. See http://groups.google.com/groups?&selm=1460178%40hplred.HPL.HP.COM&rnum=7

Tom Ace

 

[David L. Johnso]

On Thu, 29 May 2003 15:05:18 +0000, Harris wrote:

> David L. Johnson <[email protected]> wrote:
>> Italian threaded bikes (no longer done this way) had both cups right-hand thread, and the right
>> cup could loosen.
>
> Is that right? Italian BBs now have left hand thread on the right? When did that change?

I was under the impression that most manufacturers had gone over to ISO standards, but apparently
not. My apologies.

--

David L. Johnson

__o | The trouble with the rat race is that even if you win you're _`\(,_ | still a rat. --Lilly
Tomlin (_)/ (_) |

 

[A Muzi]

> David L. Johnson <[email protected]> wrote:
> > Italian threaded bikes (no longer done this way) had both cups right-hand thread, and the right
> > cup could loosen.

"Harris" <[email protected]> wrote in message
news:[email protected]...
> Is that right? Italian BBs now have left hand thread on the right? When did that change?

Very recently. Bianchi several years ago, Basso this year. You'll see a further migration to BSC, I
predict, until Italian 36mm threads are all gone within a few years. The pressures on a manufacturer
to switch are enormous at this point.

That being said, not all Italian manufacturers have gone BSC yet and, as Peter notes, reasonable
care in assembly can make this a non-issue. Unfiortunately, reasonable care is largely unknown at
assembly in this industry. . .

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

 

[Guy Tedesco]

[email protected] (Qui si parla Campagnolo) wrote in message
news:<[email protected]>...
> acorn-<< i have to keep readjusting my bottom bracket as it keeps getting loose. it is not a
> cartridge bottom bracket. it is a standard bearing set-up with ball bearings in retainer rings. is
> there a reason why an adjustment keeps needing to be done .
>
> I say have the BB shell prepped, that is faced to make the two surfaces parallel....
>
>
> Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
> (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

thanks peter in your email you said you charge 20 bucks. if that's all then i will have
the bb faced.

 

[Jasper Janssen]

On Thu, 29 May 2003 15:20:06 -0700, Tom Ace <[email protected]> wrote:
>Jasper Janssen wrote:
>
>> Which forces unscrew cups, anyway? it's not friction in the bearing itself, I think -- to take
>> the extreme case, if a bearing seized you'd be *un*threading the cups by pedaling in the normal
>> direction, unless I'm flipping something over in my mind.
>
>Precession. See http://groups.google.com/groups?&selm=1460178%40hplred.HPL.HP.COM&rnum=7

I see. I think. Thanks.

Jasper

 

[Jobst Brandt]

Peter Chisholm writes:

>> Which forces unscrew cups, anyway? it's not friction in the bearing itself, I think.

> NOT an engineer but I have been told is the reverse movement of the balls as the crank rotates
> forward. Not gonna even try to remember the 'word' or the eingineers will throw their striped hat
> off and yell at me...

Oh don't pretend! You've been in this newsgroup long enough to have seen the explanation of
precession often. Playing dumb will get you a dunce cap. This is not a good idea for an operator of
a bicycle shop. Cut it out!

Jobst Brandt [email protected] Palo Alto CA

 

[Jasper Janssen]

On 30 May 2003 12:55:46 GMT, [email protected] (Qui si parla Campagnolo) wrote:

>jasper-<< Which forces unscrew cups, anyway? it's not friction in the bearing itself, I think.
>
>NOT an engineer but I have been told is the reverse movement of the balls as the crank rotates
>forward. Not gonna even try to remember the 'word' or the eingineers will throw their striped hat
>off and yell at me....

The bearing balls *also* move forward in the cup, just slower than the cranks. It's the cup that's
getting unscrewed, not the cranks (in relation to which they do move backwards), so this doesn't
seem to have anything to do with reality. Jasper

 

[Tom Ace]

A Muzi wrote:

> That being said, not all Italian manufacturers have gone BSC yet and, as Peter notes, reasonable
> care in assembly can make this a non-issue.

Not the choice of wording I would use. Italian right cups need to be tightened with more torque than
is normal for a properly-designed threaded fastener of this size. It's not "reasonable care", it's
special-case care.

Tom Ace

 

[A Muzi]

> A Muzi wrote:
> > That being said, not all Italian manufacturers have gone BSC yet and,
as
> > Peter notes, reasonable care in assembly can make this a non-issue.

"Tom Ace" <[email protected]>, aware of the issue but splitting hairs, wrote in message
news:[email protected]...
> Not the choice of wording I would use. Italian right cups need to be tightened with more torque
> than is normal for a properly-designed threaded fastener of this size. It's not "reasonable care",
> it's special-case care.

OK, but we are saying the same thing, I think. We're in the realm of semantics here.

Knowing the thread at hand, the assembler either greases the BSC/Swiss cup at about 40pounds or
locktites the Italian/French cup at 65 pounds. That's not rocket science.

The traditional loose-bearing right cup tool is used with a 24" extender tube and is used by pulling
that tube with one hand while pressing upward on the frame with the other. Modern throwaway units
are installed with a Tacx tool and a 24" adjustable wrench held in the same manner.

From what I've seen lately, Italian threaded BBs installed at home or in poorly tooled shops use a
tool which does not bolt to the spindle and so cams out well before proper torque in both BSC
_and_ Italian!
--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

 

[Bruce Jackson]

[email protected] (Qui si parla Campagnolo) wrote in message
news:<[email protected]>...

> Italian works fine if the BB is installed correctly, on a prepped frameset. English threading was
> an answer to **** poor wrenching. Changing a design to make something cheaper, easier, not likely
> to get gooned up, is not uncommon(radial laced front wheels for example).

I had a Windsor with Italian threads that I rode in the '70's that no amount of tightening would
keep the fixed cup in. I used to put the fixed cup in a vice and use the whole frame for leverage to
tighten it but always a few thousand miles later it would loosen. Of course this was not a very high
quality bike and I doubt it ever saw a Campy tool kit (I didn't even know about such things back
then). Other than that I'd agree that I've never had a problem with Italian fixed cups backing off.

> I have been using Italian threaded BBs for over 17 years and have never had a right cup loosen---

Agreed that an Italian fixed cup will not back off if installed correctly. But since there is no
advantage to Italian threads why shouldn't Italian manufacturers adopt ISO dimensions?

Bruce
--
Bruce Jackson - Sr. Systems Programmer - DMSP, a M/A/R/C Group company

 

[Jasper Janssen]

On 02 Jun 2003 12:43:37 GMT, [email protected] (Qui si parla Campagnolo) wrote:

>I guess ya ought to ask an Italian that. Some frame builders like Italian since the BB shell is
>larger and also wider, a good thing for some framesets.

It'd be theoretically possible to have an Italian sized BB with right/left threading, rather than
the Italian standard threading.

>ISO was an answer to inexpensive framesets, sluggish BBs(like some cart BBs) and bike shops w/o the
>proper tools.

ISO (in its BSA form) has been around for nearly a hundred years. It itself can't have been caused
by what you say. If you mean Italian manufacturers switching to ISO, I'd venture that the real
reason is standardisation. Things are cheaper and more interchangeable when they're standardised.

Jasper

 

[Jasper Janssen]

On 03 Jun 2003 12:55:27 GMT, [email protected] (Qui si parla Campagnolo) wrote:
>jasper-<< If you mean Italian manufacturers switching to ISO, I'd venture that the real reason is
>standardisation. Things are cheaper and more interchangeable when they're standardised.
>
>"Bicycles" are a lot of things but 'standardized', they are not.

Well, no, it depends on the particular part of the bike. Some of the components (such as gearing)
are deliberately non-standardised so you have to buy everything from one manufacturer (or at least
as close to that as they can get it), but BB shells are probably one of the most standardised things
around.. Next to perhaps axle thickness (ie, the room in the dropouts must fit) and to a certain
extent length. Also, head tube and fork crown dimensions. I don't think it's a coincidence those are
all determined by the frame.

(Though, when I say standards, I'm talking more in the sense of industry/de facto standards, rather
than 100% or government set standards. Like, "Cisco sets the standard for internet routers" -- this
is true, even if they only have somewhere in the region of 30-50 percent market share.)

Jasper