BB - turn by hand?

Penny who? wrote:

Should a properly fitted BB be easily turned by hand? I took off
the cranks and its very stiff and I can only just turn the spindle
by hand. I think I know it should be easier than that! Which is a
surprise as its less than 2 years old and has probably done less
than 3000 km.

http://www.sheldonbrown.com/brandt/bb-adjust.html

What octalink BB would you recommend for a touring bike to replace
it?

(thanks to the poster that said it was probably self extracting - it
was. Damn the LBS which sold me a Shimano crank extractor to get
them (Ritchey wcs cranks) off.)

Jobst Brandt

Hank writes:

On Sep 5, 1:30Â*pm, wrote:
Should a properly fitted BB be easily turned by hand? I took off the
cranks and its very stiff and I can only just turn the spindle by
hand. I think I know it should be easier than that! Which is a surprise
as its less than 2 years old and has probably done less than 3000 km.

What octalink BB would you recommend for a touring bike to replace it?

(thanks to the poster that said it was probably self extracting - it
was. Damn the LBS which sold me a Shimano crank extractor to get them
(Ritchey wcs cranks) off.)

It should be smooth, but not effortless to turn, thanks to drag from
the seals. If you can only barely turn it by hand, it's toast.

Sounds like a good time to get that new crank, since you'll need a new
BB anyway. Don't bother replacing the current BB unless you've decided
to keep the Ritchey Crank. The cheapest you'll find a compatible BB
(the 105 BB-5500 Triple) is close to $50. Put that into your new
crank.

Is Shimano dropping the octalink design too? My understanding is that
they introduced it. Googling reveals a general derision for them for
some reason. I must say that when I was convinced I would not break
anything (confirmed they were self extracting) the cranks came off
easily.

Penny who? wrote:

Should a properly fitted BB be easily turned by hand? I took off
the cranks and its very stiff and I can only just turn the spindle
by hand. I think I know it should be easier than that! Which is a
surprise as its less than 2 years old and has probably done less
than 3000 km.

What Octalink BB would you recommend for a touring bike to replace
it?

(thanks to the poster that said it was probably self extracting -
it was. Damn the LBS which sold me a Shimano crank extractor to
get them (Ritchey WCS cranks) off.)

It should be smooth, but not effortless to turn, thanks to drag
from the seals. If you can only barely turn it by hand, it's
toast.

Sounds like a good time to get that new crank, since you'll need a
new BB anyway. Don't bother replacing the current BB unless you've
decided to keep the Ritchey Crank. The cheapest you'll find a
compatible BB (the 105 BB-5500 Triple) is close to $50. Put that
into your new crank.

Is Shimano dropping the Octalink design too? My understanding is
that they introduced it. Googling reveals a general derision for
them for some reason. I must say that when I was convinced I would
not break anything (confirmed they were self extracting) the cranks
came off easily.

That's the point, they came off easily. The history of this crank
attachment is a classic misunderstanding of the design problem. The
eight splines had no press fit and therefore had both clearance and
elastic rotational backlash that occurs when standing on both pedals,
right foot forward, followed by normal hard pedaling.

The backlash, even small as it is, was enough to unscrew the retaining
bolt and gradually back out the "easily removable crank" until it
reached the point when not enough spline (aluminum) was engaged to
withstand pedaling torque. The spline sheared, convincing Shimano
engineers that the spine was too short (weak), so they made a second
version with a longer spline.

The longer spline failed just as its predecessor did having the same
rotational backlash... Dead design!

http://www.sheldonbrown.com/brandt/l...ng-cranks.html

Jobst Brandt

On Sep 5, 3:30*pm, wrote:
Should a properly fitted BB be easily turned by hand? I took off the
cranks and its very stiff and I can only just turn the spindle by
hand. I think I know it should be easier than that! Which is a surprise
as its less than 2 years old and has probably done less than 3000 km.

What octalink BB would you recommend for a touring bike to replace it?

(thanks to the poster that said it was probably self extracting - it
was. Damn the LBS which sold me a Shimano crank extractor to get them
(Ritchey wcs cranks) off.)

Late to the party here but a couple of things:

Was the bottom bracket shell on your bike "faced" before the BB went
in, on assembly?

(quoting from:

http://www.parktool.com/repair/readhowto.asp?id=97 )

Most bottom bracket shells have an internal thread to accept bottom
bracket bearing units from numerous manufacturers. If these threads
are not in acceptable condition, they may need preparation. Threads
may need realignment, or may have weld splatter from manufacturing
that prevents the threading of the bearings. Shells may be out of
round due to welding during manufacturing. Additionally, some bearing
system benefit from having the faces of the shell square to improve
bearing adjustment and bearing longevity. If the shell faces are
deformed, and are not parallel to one another, the left and right
bearing may not be concentric to one another. Machining the shell face
improves concentricity. (end quote from Park Tools website)

Just yesterday "the person I entrust to the mechanical care of my
bicycles" (AKA "my" mechanic) told me "No one is facing BB's
anymore"-- meaning, he very commonly sees bikes where that important
step in assembly was omitted. And then BB's don't work right, and wear
out quickly.

Maybe that was the beginning of your BB woes, so to speak?

I wouldn't pretend to know what the "best choice" replacement course
of action might be for you-- including replacing your LBS g-- but
for one thing, Octalink may well have its problems, but apparently so
do other brands/systems. Noting further that Octalink doesn't "always
fail" from what I gather, especially with lighter riders.

Perhaps a question to ask the experts, incl. those "in the business"
who read and post here might be a description of your bike, incl.
brand, and the parts on it, and your use ("touring", etc.) to see what
recommendations might be made IRT replacing the BB (with correct
spindle length) or indeed the entire crankset.

Oh yeah, I'd take that BB tool back, especially if someone actually
looked at your bike/crank/BB and sold you the wrong tool.
--D-y

writes:

Penny who? wrote:

Should a properly fitted BB be easily turned by hand? I took off
the cranks and its very stiff and I can only just turn the spindle
by hand. I think I know it should be easier than that! Which is a
surprise as its less than 2 years old and has probably done less
than 3000 km.

What Octalink BB would you recommend for a touring bike to replace
it?

(thanks to the poster that said it was probably self extracting -
it was. Damn the LBS which sold me a Shimano crank extractor to
get them (Ritchey WCS cranks) off.)

It should be smooth, but not effortless to turn, thanks to drag
from the seals. If you can only barely turn it by hand, it's
toast.

Sounds like a good time to get that new crank, since you'll need a
new BB anyway. Don't bother replacing the current BB unless you've
decided to keep the Ritchey Crank. The cheapest you'll find a
compatible BB (the 105 BB-5500 Triple) is close to $50. Put that
into your new crank.

Is Shimano dropping the Octalink design too? My understanding is
that they introduced it. Googling reveals a general derision for
them for some reason. I must say that when I was convinced I would
not break anything (confirmed they were self extracting) the cranks
came off easily.

That's the point, they came off easily. The history of this crank
attachment is a classic misunderstanding of the design problem. The
eight splines had no press fit and therefore had both clearance and
elastic rotational backlash that occurs when standing on both pedals,
right foot forward, followed by normal hard pedaling.

The backlash, even small as it is, was enough to unscrew the retaining
bolt and gradually back out the "easily removable crank" until it
reached the point when not enough spline (aluminum) was engaged to
withstand pedaling torque. The spline sheared, convincing Shimano
engineers that the spine was too short (weak), so they made a second
version with a longer spline.

The longer spline failed just as its predecessor did having the same
rotational backlash... Dead design!

http://www.sheldonbrown.com/brandt/l...ng-cranks.html

Jobst Brandt

Well, even more interesting, and embarassingly, it turned out not to be
an octalink at all.

It was a 68mm x 113mm ISIS. needless to say the biggest bike shop in the
area sold me an XT octalink which I got home, dismantled my bike and
found did not fit.

Having just spent the morning traipsing around the town to get nothing
but shakes of the head I have decided to go back to my LBS (which sold
me the Ritchey cranks and the BB (they fitted it) 2 years ago) and
demand my money back as I made very clear to them I wanted easily
replaceable and serviceable parts. Since I spent a lot of money there in
the past I dont expect too much of a problem.....

So lets see : SHimano square taper, "power splice", ISIS and Octalink?
Any more the unwary should know about?

I am guessing now that my best bet is to lose the cranks and, as Hank
suggested, use this opportunity to get my TA or Stronglight cranks :-;

writes:

Penny who? wrote:

Should a properly fitted BB be easily turned by hand? I took off
the cranks and its very stiff and I can only just turn the spindle
by hand. I think I know it should be easier than that! Which is a
surprise as its less than 2 years old and has probably done less
than 3000 km.

What Octalink BB would you recommend for a touring bike to replace
it?

(thanks to the poster that said it was probably self extracting -
it was. Damn the LBS which sold me a Shimano crank extractor to
get them (Ritchey WCS cranks) off.)

It should be smooth, but not effortless to turn, thanks to drag
from the seals. If you can only barely turn it by hand, it's
toast.

Sounds like a good time to get that new crank, since you'll need a
new BB anyway. Don't bother replacing the current BB unless you've
decided to keep the Ritchey Crank. The cheapest you'll find a
compatible BB (the 105 BB-5500 Triple) is close to $50. Put that
into your new crank.

Is Shimano dropping the Octalink design too? My understanding is
that they introduced it. Googling reveals a general derision for
them for some reason. I must say that when I was convinced I would
not break anything (confirmed they were self extracting) the cranks
came off easily.

That's the point, they came off easily. The history of this crank

Interesting, but strange way of looking at it. Self extracting doesnt
mean the design need be a general failure unless the spline is a "must
have" for self extracting. My crank certainly never came loose but I
must admit in the time it was on my bike I only did 2 relatively short
(and flat) camping trips with a fully loaded bike.

attachment is a classic misunderstanding of the design problem. The
eight splines had no press fit and therefore had both clearance and
elastic rotational backlash that occurs when standing on both pedals,
right foot forward, followed by normal hard pedaling.

The backlash, even small as it is, was enough to unscrew the retaining
bolt and gradually back out the "easily removable crank" until it
reached the point when not enough spline (aluminum) was engaged to
withstand pedaling torque. The spline sheared, convincing Shimano
engineers that the spine was too short (weak), so they made a second
version with a longer spline.

How did they manage to come to the wrong design twice in a row? I
thought these guys were specialists :-;


The longer spline failed just as its predecessor did having the same
rotational backlash... Dead design!

http://www.sheldonbrown.com/brandt/l...ng-cranks.html

Jobst Brandt

--

" writes:


Oh yeah, I'd take that BB tool back, especially if someone actually
looked at your bike/crank/BB and sold you the wrong tool.
--D-y

No. I will move back to a square BB spindle I think. They certainly seem
more common.

In article ,
wrote:

Well, even more interesting, and embarassingly, it turned out not to
be an octalink at all.

It was a 68mm x 113mm ISIS.

Huh. I didn't know Ritchey made an ISIS crank; me recollection was that
he had gone with the Octalink design. Live and learn.

My ISIS BB (Truvativ Rouleur cranks and BB, IIRC) is very sensitive to
overtightening the retaining rings and over-preloading the bearing. It
becomes stiff just as you describe. As I mentioned in another post,
this is the first thing I would check before spending money.

Tim McNamara writes:

In article ,
wrote:

Well, even more interesting, and embarassingly, it turned out not to
be an octalink at all.

It was a 68mm x 113mm ISIS.

Huh. I didn't know Ritchey made an ISIS crank; me recollection was that
he had gone with the Octalink design. Live and learn.

WCS. A few years old. Found next to zero information about them on the
net hence this on going thread. Still, I learnt a fair bit.


My ISIS BB (Truvativ Rouleur cranks and BB, IIRC) is very sensitive to
overtightening the retaining rings and over-preloading the bearing. It
becomes stiff just as you describe. As I mentioned in another post,
this is the first thing I would check before spending money.

This make a cracking sound too. I had it out and it actually sticks
solid every few turns (by hand) too.

Also I read the wiki and it says this type of design is not recommended
for a MTB (and from this I think a touring bike too) since the bearings
are smaller and thus take less load. Sound correct?

http://en.wikipedia.org/wiki/Bottom_bracket#ISIS_Drive

Scarily I can not find my crank on Google. It is a triple with silver
blue anodizing.

Penny who? wrote:

Is Shimano dropping the Octalink design too? My understanding is
that they introduced it. Googling reveals a general derision for
them for some reason. I must say that when I was convinced I
would not break anything (confirmed they were self extracting) the
cranks came off easily.

That's the point, they came off easily. The history of this crank

Interesting, but strange way of looking at it. Self extracting
doesn't mean the design need be a general failure unless the spline
is a "must have" for self extracting. My crank certainly never came
loose but I must admit in the time it was on my bike I only did 2
relatively short (and flat) camping trips with a fully loaded bike.

attachment is a classic misunderstanding of the design problem.
The eight splines had no press fit and therefore had both clearance
and elastic rotational backlash that occurs when standing on both
pedals, right foot forward, followed by normal hard pedaling.

The backlash, even small as it is, was enough to unscrew the
retaining bolt and gradually back out the "easily removable crank"
until it reached the point when not enough spline (aluminum) was
engaged to withstand pedaling torque. The spline sheared,
convincing Shimano engineers that the spine was too short (weak),
so they made a second version with a longer spline.

How did they manage to come to the wrong design twice in a row? I
thought these guys were specialists :-;

I think I explained that in depth. The spline did not fail because it
was to short (not enough metal), but because it has backlash that
unscrews the retaining bolt. The mechanism for this failing is not
understood by many engineers that work with this sort of interface.
Similarly, the need for left hand thread on left pedals is also not
understood. It is not to prevent unscrewing from frictional drag of
pedal bearings as is commonly believed.

http://www.sheldonbrown.com/brandt/left.html

The longer spline failed just as its predecessor did having the
same rotational backlash... Dead design!

http://www.sheldonbrown.com/brandt/l...ng-cranks.html
--
Jobst Brandt