BB technologies.

"Defendit numerus." - Anon.

Qui si parla Campagnolo said:

JUST CUT A TOASTED ULTEGRA/6500 bb apart and it's 7-7/32 balls on each
side, round ones, not needle bearings

I wouldn't deny another mechanic the guilty pleasure of breaking
something, but this particular egg had been cracked over three years
ago:

http://groups.google.com/group/rec.bicycles.tech/msg/bdb48b8cb1123c67?hl=en&

.. . . a thread in which you participated yourself.
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Since 1983
Our catalog of track equipment: online since 1996
Phone: 305-273-4440
http://www.businesscycles.com
-------------------------------

Jobst Brandt said:

Quoted message said:

And, I wonder why Shimano came up with Octalink II ? Must have been
to solve all those non-existent problems, right? ;-)

I think I explained that a few times. Octalink fails for "goofy
footed riders", those who stand with right foot forward while
coasting. This causes reverse torque on the spindle and because the
Octalink is not a press fit, it rotates... back and forth with each
standing on the pedals (over rough ground, for instance).

The Octalink spines sheared off and the Shimano engineers did not
recognize that it was not for long enough spline teeth that it failed
but because it unscrewed and disengaged the spline to a point where it
WAS too weak and sheared off. Octalink II got longer spline
engagement that took a little longer to unscrew and shear off.

Quoted message said:

Quoted message said:

With respect, language like "walking away" is repeating biased and
misinformed r.b.t theatrics.

Quoted message said:

With respect, that's nonsense. Walking away is exactly what they
are doing. What do you think the long term availability of Octalink
BB's will be?

Shimano had to kill it because failures are guaranteed. It's like
Campagnolo dropping the Delta brake. It was a stylish but dangerous
dog!

I'm not sure that Shimano is so smart. Have you seen the changes to the
crank/spindle attachment in the new XTR crank? I haven't seen it in person,
but from the drawings on the Shimano site, it looks like they dropped the
pinch bolt and went back to the Octalink design for the left side arm.

The exploded view:

http://tinyurl.com/2rqcwd

The service instructions:

http://tinyurl.com/2muu4o

They seem to acknowledging that the fixing bolt unscrews with their note
under step 5 of the installation instructions:
"Note: The crank arm fixing bolt should be periodically retightened."

It looks like they might be abandoning the pinch bolts in order to add a
bottom bracket bearing pre-load adjustment nut. I wonder how well the pinch
bolts actually worked? I remember reading about cranks falling off when the
design first came out, but I assumed that they were cases where people were
forgetting to tighten the pinch bolts.

Quoted message said:

On Mon, 05 Feb 2007 22:16:07 GMT, Dan Connelly

d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m said:

Quoted message said:

Dear Dan,

Where do you feel this difference?

If you're applying the same power in both cases, the "feel" at your
foot should be the same, since it's pushing just as hard in both
cases.

If more of the same power reaches the contact patch because of more
efficient power transmission, you'll go slightly faster. Are you
noticing a measurable speed difference and a distinctly higher
cadence in the same gear?

No -- I just spin the pedals backwards, freewheeling the cassette,
and it spins substantially further with my Ultegra BB than with the
external bottom brackets (alhough I haven't tried Campy, just
Shimano, FSA, and SRAM).

Of course, you would be correct if you suggested this may also be
due to the freehub body.

Dan

Dear Dan,

A quick and easy method of demonstrating the tiny amount of drag in a
typical bottom bracket is to pull the chain off the front sprocket,
level the pedals, and see how many dimes you can stack on a pedal
before it drops:

http://groups.google.com/group/rec.bicycles.tech/msg/ffb74cfbe0ef2f1f

An elderly Shimano cartridge will drop when a third dime is laid on a
pedal, suggesting that there's not likely to be a dime's worth of
difference between it and the finest bottom bracket available.

Cheers,

Carl Fogel

What if you use gold?

--
Phil

M-gineering said:

Quoted message said:

JUST CUT A TOASTED ULTEGRA/6500 bb apart and it's 7-7/32 balls on each
side, round ones, not needle bearings

Cutting sounds like hard work. Pull the seals and the plastic bearing
retainers. Move all bearings to the bottom and snap the axle upwards

The cartridge bodies are formed in a way that keeps the balls in each
end captive in their respective orbits around the spindle, so simply
removing the seals won't be enough to free them. The way they get all
this stuff inside the cartridge shell is a design that would impress
even builders of ships in bottles.
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Since 1983
Our catalog of track equipment: online since 1996
Phone: 305-273-4440
http://www.businesscycles.com
-------------------------------

Bill Sornson said:

Quoted message said:

Quoted message said:

... Octalink fails for "goofy footed riders", those who stand with
right foot forward while coasting.

Quoted message said:

Quoted message said:

i do that and i've never had an octalink crank loosen. but i also
make sure i tighten the crank per manufacturer spec. go figure.

Quoted message said:

FWIW, I have one mountain bike and two road bikes, all with lots
(thousands) of Octalink miles. I coast exclusively "goofy footed",
as left foot forward just feels unnatural to me. (I'm left handed;
right footed.) Never had a properly tightened crank loosen, even a
little.

Quoted message said:

BTW, at the risk of sounding thick(er than usual), right foot
forward and left rearward puts pressure on the cranks in the
"tightening directions".

If the crank moves fore and aft it makes little difference which
occurs when, the friction on the bolt being unaffected by direction.

Quoted message said:

I suppose I can see how that /could/ work to loosen the bolts, but
it seems to me that they'd have to be too loose (on la Trek) in the
first place for any real-world problem; and non-goofy footed
coasters would also have issues (different phenomenon; same result).

Please explain. The only reverse torque in crank spindles occurs when
standing goofy footed and that is the only movement that unscrews
retaining bolts.

It depends on how the interface is lubricated and how tight the
retaining bolt is. If friction between retaining bolt thread is
greater than the bolt head against the crank, the motion will not
unscrew the bolt. That it didn't occur with your cranks is no
evidence that it doesn't occur with others. In fact it has occurred
with others often enough that Shimano engineers came out with a longer
spline, believing the spline was damaged by force instead of gradual
disengagement.

Jobst Brandt

Quoted message said:

A Muzi said:

Andrew Muzi, who ran errands today on a pair of 1966 Record Pista arms
with dependable install-and-forget square tapers.

Chalo said:

For me, it's more like "install and forget what happened in the few
hours before and after the faceplant I took when my square taper
snapped off".

Square taper spindles, carbon stems and handlebars, Ti pedal spindles,
1" aluminum steer tubes, 28 spoke wheels. They all have their place,
but my place ain't it.

A big diameter spindle really is better, inasmuch as a bearing failure
is better than a crankarm suddenly parting ways with the bike.
Dramatically improved stiffness is a welcome side benefit.

I machined an outboard BB in 1998 so that I could put a strong
American BB and a strong 22mm spindle in a British-threaded bike frame
that didn't have room for them. I'm glad to see that the industry has
finally followed my lead, but I think it would be easier if they just
used the damn American shell that represents a much better solution to
the problem anyway.

We don't disagree.

Yes, you may be an outlying data point.

For 'medium Italian guys', not to worry! Yes, everything breaks in some
measurable ratio but the design has proved acceptable for most riders on
most bikes, safely, for, what, 75 years? Not perfect but other advantages:
cheap, available, large installed base of service parts/tools, wide
swath of quality choices.
No, not perfect. Just not terrible, either, for most riders.

p.s. Yes, I own an old set of 28h wheels, 290g rims, lots of miles,
still straight. All my bikes are 1" threaded.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Andrew Lee said:

Quoted message said:

Quoted message said:

And, I wonder why Shimano came up with Octalink II ? Must have been
to solve all those non-existent problems, right? ;-)

Quoted message said:

Quoted message said:

I think I explained that a few times. Octalink fails for "goofy
footed riders", those who stand with right foot forward while
coasting. This causes reverse torque on the spindle and because the
Octalink is not a press fit, it rotates... back and forth with each
standing on the pedals (over rough ground, for instance).

Quoted message said:

Quoted message said:

The Octalink spines sheared off and the Shimano engineers did not
recognize that it was not for long enough spline teeth that it failed
but because it unscrewed and disengaged the spline to a point where it
WAS too weak and sheared off. Octalink II got longer spline
engagement that took a little longer to unscrew and shear off.

Quoted message said:

Quoted message said:

Quoted message said:

> With respect, language like "walking away" is repeating biased and
> misinformed r.b.t theatrics.

Quoted message said:

Quoted message said:

Quoted message said:

With respect, that's nonsense. Walking away is exactly what they
are doing. What do you think the long term availability of Octalink
BB's will be?

Quoted message said:

Quoted message said:

Shimano had to kill it because failures are guaranteed. It's like
Campagnolo dropping the Delta brake. It was a stylish but dangerous
dog!

Quoted message said:

I'm not sure that Shimano is so smart. Have you seen the changes to the
crank/spindle attachment in the new XTR crank? I haven't seen it in person,
but from the drawings on the Shimano site, it looks like they dropped the
pinch bolt and went back to the Octalink design for the left side arm.

Quoted message said:

The exploded view:

http://tinyurl.com/2rqcwd

Quoted message said:

The service instructions:

http://tinyurl.com/2muu4o

Quoted message said:

They seem to acknowledging that the fixing bolt unscrews with their
note under step 5 of the installation instructions: "Note: The crank
arm fixing bolt should be periodically retightened."

It is possible that they still don't understand why the bolt loosens.
The apparently don't understand why left pedals need a left hand
thread or they would probably put a tapered face on the pedal spindle.
It may be worse than I suspect.

Quoted message said:

It looks like they might be abandoning the pinch bolts in order to add a
bottom bracket bearing pre-load adjustment nut. I wonder how well the pinch
bolts actually worked? I remember reading about cranks falling off when the
design first came out, but I assumed that they were cases where people were
forgetting to tighten the pinch bolts.

Pinch bolts have served well for many applications. I don't see that
the 7800 series is giving up on that.

Jobst Brandt

Quoted message said:

Jobst Brandt said:

Quoted message said:

And, I wonder why Shimano came up with Octalink II ? Must have been
to solve all those non-existent problems, right? ;-)

I think I explained that a few times. Octalink fails for "goofy
footed riders", those who stand with right foot forward while
coasting. This causes reverse torque on the spindle and because the
Octalink is not a press fit, it rotates... back and forth with each
standing on the pedals (over rough ground, for instance).

The Octalink spines sheared off and the Shimano engineers did not
recognize that it was not for long enough spline teeth that it failed
but because it unscrewed and disengaged the spline to a point where it
WAS too weak and sheared off. Octalink II got longer spline
engagement that took a little longer to unscrew and shear off.

Quoted message said:

> With respect, language like "walking away" is repeating biased and
> misinformed r.b.t theatrics.
With respect, that's nonsense. Walking away is exactly what they
are doing. What do you think the long term availability of Octalink
BB's will be?

Shimano had to kill it because failures are guaranteed. It's like
Campagnolo dropping the Delta brake. It was a stylish but dangerous
dog!

Andrew Lee said:

I'm not sure that Shimano is so smart. Have you seen the changes to the
crank/spindle attachment in the new XTR crank? I haven't seen it in person,
but from the drawings on the Shimano site, it looks like they dropped the
pinch bolt and went back to the Octalink design for the left side arm.

The exploded view:

http://tinyurl.com/2rqcwd

The service instructions:

http://tinyurl.com/2muu4o

They seem to acknowledging that the fixing bolt unscrews with their note
under step 5 of the installation instructions:
"Note: The crank arm fixing bolt should be periodically retightened."

It looks like they might be abandoning the pinch bolts in order to add a
bottom bracket bearing pre-load adjustment nut. I wonder how well the pinch
bolts actually worked? I remember reading about cranks falling off when the
design first came out, but I assumed that they were cases where people were
forgetting to tighten the pinch bolts.

I got my [free] used Record cranks in 1995 when I built my fixie. I
rebuilt the BB in 2001. Except for those 2 days I haven't touched the
cranks or bolts. Probably should redo the bearings one of these years . . .
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Jobst Brandt said:

Andrew Lee said:

It looks like they might be abandoning the pinch bolts in order to add a
bottom bracket bearing pre-load adjustment nut. I wonder how well the
pinch
bolts actually worked? I remember reading about cranks falling off when
the
design first came out, but I assumed that they were cases where people
were
forgetting to tighten the pinch bolts.

Pinch bolts have served well for many applications. I don't see that
the 7800 series is giving up on that.

Jobst Brandt

I hope they don't give it up either, but we'll see when Dura-Ace is updated
next year. I'm guessing that they will use the same no pinch bolt system as
the new XTR.

I just looked at the 7800 service instructions, and I can see how
installations can go wrong. If the two pinch bolts are not tightened
alternately in stages, they can bind before they lock down on the spindle.
So those failures that I mentioned were probably installation errors.

Non-Squid said:

Quoted message said:

On Mon, 05 Feb 2007 22:16:07 GMT, Dan Connelly

d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m said:

[email hidden] wrote:
> Dear Dan,
>
> Where do you feel this difference?
>
> If you're applying the same power in both cases, the "feel" at your
> foot should be the same, since it's pushing just as hard in both
> cases.
>
> If more of the same power reaches the contact patch because of more
> efficient power transmission, you'll go slightly faster. Are you
> noticing a measurable speed difference and a distinctly higher
> cadence in the same gear?

No -- I just spin the pedals backwards, freewheeling the cassette,
and it spins substantially further with my Ultegra BB than with the
external bottom brackets (alhough I haven't tried Campy, just
Shimano, FSA, and SRAM).

Of course, you would be correct if you suggested this may also be
due to the freehub body.

Dan

Dear Dan,

A quick and easy method of demonstrating the tiny amount of drag in a
typical bottom bracket is to pull the chain off the front sprocket,
level the pedals, and see how many dimes you can stack on a pedal
before it drops:

http://groups.google.com/group/rec.bicycles.tech/msg/ffb74cfbe0ef2f1f

An elderly Shimano cartridge will drop when a third dime is laid on a
pedal, suggesting that there's not likely to be a dime's worth of
difference between it and the finest bottom bracket available.

Cheers,

Carl Fogel

What if you use gold?

Dear Phil,

Assuming that you can find 24 carat gold in 2.268 gram chunks (roughly
what a dime weighs) . . .

http://goldprice.org/us-gold-price.html

A little under fifty bucks.

But whether it's a gram of gold or a gram of feathers, it still won't
be a dime's worth of difference at the contact patch. The difference
in drag between reasonably adjusted bottom brackets isn't enough to be
detected by a human finger moving back and forth between them, much
less a hind leg on a pedal.

Cheers,

Carl Fogel

A Muzi said:

What fun is that? Much better with a disc grinder:
http://www.yellowjersey.org/photosfromthepast/FIRE.JPG

Sure, if you want [censored] and burnmarks all over the workshop and customer
bikes.
(and anyone who starts up an anglegrinder without a full facemask is an
idiot. period)

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

Quoted message said:

Both Shimano and Campagnolo use new BB designs that are a response to
the failings of the square taper. This is not idle design work.

You're joking. This is marketing people copying each other. If an
engineer is involved he has skipped bearings 101

Quoted message said:

There are serious flaws that cause these design changes even though it
is not common knowledge what fails.

Salesfigures are usually kept private 😉

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

John Dacey said:

M-gineering said:

Quoted message said:

JUST CUT A TOASTED ULTEGRA/6500 bb apart and it's 7-7/32 balls on each
side, round ones, not needle bearings

Cutting sounds like hard work. Pull the seals and the plastic bearing
retainers. Move all bearings to the bottom and snap the axle upwards

The cartridge bodies are formed in a way that keeps the balls in each
end captive in their respective orbits around the spindle, so simply
removing the seals won't be enough to free them.

i think you missed the "And the plastic bearing retainers" bit

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

[email hidden] wrote:
The difference

Quoted message said:

in drag between reasonably adjusted bottom brackets isn't enough to be
detected by a human finger moving back and forth between them, much
less a hind leg on a pedal.

The seals and balls of an external bottom bracket act on a much larger
radius. The extra drag is very noticable when working on the bike. On
the road is probably a different matter

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

jim beam wrote:
your argument is that square taper does the same job as octalink -

Quoted message said:

that's true. but octalink is stiffer, lighter, doesn't work loose like
square tapers often do

Playing team mechanic I always check(ed) the LH crankbolt. Roughly 50%
will be loose. Next time back they will be loose again

---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

M-gineering said:

jim beam wrote:
your argument is that square taper does the same job as octalink -

Quoted message said:

that's true. but octalink is stiffer, lighter, doesn't work loose
like square tapers often do

Playing team mechanic I always check(ed) the LH crankbolt. Roughly 50%
will be loose. Next time back they will be loose again

are you using a torque wrench? i'm no lightweight and i'm no slug
either, and i've never had one loosen. i torque per manufacturer spec.
it's tight. 50-70Nm is not something you can easily achieve with a 6"
hex wrench.

Quoted message said:

Andrew Lee said:

Quoted message said:

> And, I wonder why Shimano came up with Octalink II ? Must have been
> to solve all those non-existent problems, right? ;-)

Quoted message said:

Quoted message said:

I think I explained that a few times. Octalink fails for "goofy
footed riders", those who stand with right foot forward while
coasting. This causes reverse torque on the spindle and because the
Octalink is not a press fit, it rotates... back and forth with each
standing on the pedals (over rough ground, for instance).

Quoted message said:

Quoted message said:

The Octalink spines sheared off and the Shimano engineers did not
recognize that it was not for long enough spline teeth that it failed
but because it unscrewed and disengaged the spline to a point where it
WAS too weak and sheared off. Octalink II got longer spline
engagement that took a little longer to unscrew and shear off.

Quoted message said:

Quoted message said:

>> With respect, language like "walking away" is repeating biased and
>> misinformed r.b.t theatrics.

Quoted message said:

Quoted message said:

> With respect, that's nonsense. Walking away is exactly what they
> are doing. What do you think the long term availability of Octalink
> BB's will be?

Quoted message said:

Quoted message said:

Shimano had to kill it because failures are guaranteed. It's like
Campagnolo dropping the Delta brake. It was a stylish but dangerous
dog!

Quoted message said:

I'm not sure that Shimano is so smart. Have you seen the changes to the
crank/spindle attachment in the new XTR crank? I haven't seen it in person,
but from the drawings on the Shimano site, it looks like they dropped the
pinch bolt and went back to the Octalink design for the left side arm.

Quoted message said:

The exploded view:

http://tinyurl.com/2rqcwd

Quoted message said:

The service instructions:

http://tinyurl.com/2muu4o

Quoted message said:

They seem to acknowledging that the fixing bolt unscrews with their
note under step 5 of the installation instructions: "Note: The crank
arm fixing bolt should be periodically retightened."

It is possible that they still don't understand why the bolt loosens.

such condescension. have /you/ bothered to take into account the wedge
effect of the radiused spline roots in your, er, calculations? before
you continue your guesswork, you need to ask basic questions about
whether mechanics are following manufacturer instructions.

Quoted message said:

The apparently don't understand why left pedals need a left hand
thread or they would probably put a tapered face on the pedal spindle.
It may be worse than I suspect.

Quoted message said:

It looks like they might be abandoning the pinch bolts in order to add a
bottom bracket bearing pre-load adjustment nut. I wonder how well the pinch
bolts actually worked? I remember reading about cranks falling off when the
design first came out, but I assumed that they were cases where people were
forgetting to tighten the pinch bolts.

Pinch bolts have served well for many applications. I don't see that
the 7800 series is giving up on that.

Jobst Brandt

M-gineering said:

Quoted message said:

Both Shimano and Campagnolo use new BB designs that are a response to
the failings of the square taper. This is not idle design work.

You're joking. This is marketing people copying each other.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
BINGO!

Marten Gerritsen said:

Quoted message said:

your argument is that square taper does the same job as octalink -
that's true. but octalink is stiffer, lighter, doesn't work loose
like square tapers often do

Quoted message said:

Playing team mechanic I always check(ed) the LH crank bolt. Roughly
50% will be loose. Next time back they will be loose again

What makes you believe that left crank bolts ate more liable to loosen
than right ones? What mechanism loosens them? What "loosens" right
AND left square taper crank bolts is well understood. So what's the
cause with Octalink?

Jobst Brandt

Ozark Bicycle said:

M-gineering said:

Quoted message said:

Both Shimano and Campagnolo use new BB designs that are a response to
the failings of the square taper. This is not idle design work.

You're joking. This is marketing people copying each other.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
BINGO!

why the fear and irrationality about "marketing"? this is a persistent
thread on r.b.t and consistent with an inability to think for ones self.
not all development or innovation is marketing. not all marketing is
evil.