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Main
Date: 07 May 2007 20:29:41
From: PJay
Subject: Correct way to fit cartridge bottom brackets
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I'm trying to develop a feel for fitting cartridge bottom brackets
(Octalink). Shimano specs. state that both the cartridge and non-driveside
adapter should be torqued to between 50-70Nm. I have a torque wrench but
it's pretty old and very probably inaccurate and in any event, more often
than not when i mention torque wrenches it's suggested that I try to develop
a 'feel' for correct tightness (not that easy when only working on your own
bike - the BB usually only comes out twice a year for regreasing).
Is it okay just to go for 'nice and tight' with both flanges up tight
against the BB shell or do I need to be more accurate than this? I
understand that a loose BB could damage the thread in the shell and I don't
want to risk this. Would a BB and/or adapter that were loose enough to cause
thread damage be obvious (creak or wobble) or is it more subtle than that?
Is it possible damage the theads in the BB shell or the shell itself by
overtightening?
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Date: 09 May 2007 02:04:29
From: lightninglad
Subject: Re: Correct way to fit cartridge bottom brackets
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.....snip
> One consideration is that BB shells are pretty frequently in a
> condition where an awful lot of extra friction is created by poor
> thread alignment or contamination by paint or other stuff. When you're
> torquing the BB, a certain amount of the energy you're putting into it
> gets eaten up purely in overcoming this friction.....snip......
If you have an old bearing cup you can make a useful thread cleaner by
cutting three slots with a 32 tooth hacksaw blade roughly 120 degrees
apart through the threads (at right angles.) If you chase this through
the BB thread it will clean up the threads rather like a tap. You do
the usual partial entry multiple passes to gradually remove the dirt -
removing, cleaning and re-inserting the cleaning tool until it threads
smoothly right in.
Stating the flamin' obvious, you need a left hand and right hand
cleaner!
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Date: 08 May 2007 10:55:24
From: Orin
Subject: Re: Correct way to fit cartridge bottom brackets
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On May 8, 6:07 am, "andresm...@aol.com" <andresm...@aol.com > wrote:
> On May 7, 1:29 pm, "PJay" <pauldavis...@hotmail.com> wrote:
>
> > I'm trying to develop a feel for fitting cartridge bottom brackets
> > (Octalink). Shimano specs. state that both the cartridge and non-driveside
> > adapter should be torqued to between 50-70Nm. I have a torque wrench but
> > it's pretty old and very probably inaccurate and in any event, more often
> > than not when i mention torque wrenches it's suggested that I try to develop
> > a 'feel' for correct tightness (not that easy when only working on your own
> > bike - the BB usually only comes out twice a year for regreasing).
>
> > Is it okay just to go for 'nice and tight' with both flanges up tight
> > against the BB shell or do I need to be more accurate than this? I
> > understand that a loose BB could damage the thread in the shell and I don't
> > want to risk this. Would a BB and/or adapter that were loose enough to cause
> > thread damage be obvious (creak or wobble) or is it more subtle than that?
> > Is it possible damage the theads in the BB shell or the shell itself by
> > overtightening?
>
> I've been assembling and disasembling my bikes for the past 20 years.
> I have never used a torque wrench on anything. I have never striped
> threads. In fact, I doubt that many people strip threads with
> exception of tiny aluminum bolts and nuts. Torque wrenches are
> something new. AFAIK most mecahnics didn't use torque wrenches until
> recently. I think that if you are a pro mechanic in a bike shop
> assembling several bikes a day in a hurry, you need a torque wrench so
> you can go faster w/o worrying about too much or too little torque.
> however, if you are an amateur, you'll be able to handle most jobs w/o
> a torque wrench.
Yes, most mechanics claim to have developed a feel for the correct
torque. Which meant that early customers probably got widely varying
and wrong torques. How would you like to have been the recipient of
the under-torqued square taper crank resulting in a trashed crank?
IME, amateurs under-torque BBs and cranks and over-torque the small
stuff. In fact for BBs and cranks, a suitable torque wrench will be
long enough to obtain the required torque relatively easily. Your
average 8mm allen wrench won't. A suitable torque wrench will only
cost about $20, so there's really no excuse not to use one.
Orin.
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Date: 08 May 2007 20:18:09
From: Lou Holtman
Subject: Re: Correct way to fit cartridge bottom brackets
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Orin wrote:
>
> Yes, most mechanics claim to have developed a feel for the correct
> torque. Which meant that early customers probably got widely varying
> and wrong torques. How would you like to have been the recipient of
> the under-torqued square taper crank resulting in a trashed crank?
>
> IME, amateurs under-torque BBs and cranks and over-torque the small
> stuff. In fact for BBs and cranks, a suitable torque wrench will be
> long enough to obtain the required torque relatively easily. Your
> average 8mm allen wrench won't. A suitable torque wrench will only
> cost about $20, so there's really no excuse not to use one.
>
> Orin.
>
Some people are 'proud' that they developed/have 'the feel' of the
proper torque, while any 'idiot' can do the same with a torque wrench. I
prefer the 'idiot' with the torque wrench...
Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)
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Date: 08 May 2007 21:21:56
From: PJay
Subject: Re: Correct way to fit cartridge bottom brackets
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"Lou Holtman" <lholremovethis@planet.nl > wrote in message
news:4640befd$1@news.nb.nu...
> Orin wrote:
>
>>
>> Yes, most mechanics claim to have developed a feel for the correct
>> torque. Which meant that early customers probably got widely varying
>> and wrong torques. How would you like to have been the recipient of
>> the under-torqued square taper crank resulting in a trashed crank?
>>
>> IME, amateurs under-torque BBs and cranks and over-torque the small
>> stuff. In fact for BBs and cranks, a suitable torque wrench will be
>> long enough to obtain the required torque relatively easily. Your
>> average 8mm allen wrench won't. A suitable torque wrench will only
>> cost about $20, so there's really no excuse not to use one.
>>
>> Orin.
>>
>
>
> Some people are 'proud' that they developed/have 'the feel' of the proper
> torque, while any 'idiot' can do the same with a torque wrench. I prefer
> the 'idiot' with the torque wrench...
>
> Lou
> --
> Posted by news://news.nb.nu (http://www.nb.nu)
>
It's strange how torque wrenches and bikes seem to polarise people, when I
posted about using a torque wrench lots of people told me I didn't need one,
when I post about not using one quite a few seem to recommend that I do :-)
Cranks seem particularly dependant on accurate torquing so I'm pretty sure
I'll keep using one for that, the torque wrench I have that I've used for
BBs is pretty old and second hand so I'm a little unsure that the 'feel' I
might be developing using it might be off. The good quality wrench I have
unfortunately only measures torque for right hand threads.
BBs seem to have a relatively wide range of acceptable torque so it seems
like a reasonable place to start.
I'm still keen to know whether a BB loose enough to wear the shell threads
would be obviously loose (creaky/wobbly). Overtightening a BB would seem to
need an excessive amount of force.
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Date: 08 May 2007 22:47:16
From: Lou Holtman
Subject: Re: Correct way to fit cartridge bottom brackets
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PJay wrote:
> It's strange how torque wrenches and bikes seem to polarise people, when I
> posted about using a torque wrench lots of people told me I didn't need one,
> when I post about not using one quite a few seem to recommend that I do :-)
Yes that's strange.
>
> Cranks seem particularly dependant on accurate torquing so I'm pretty sure
> I'll keep using one for that, the torque wrench I have that I've used for
> BBs is pretty old and second hand so I'm a little unsure that the 'feel' I
> might be developing using it might be off. The good quality wrench I have
> unfortunately only measures torque for right hand threads.
You bought the wrong one ;-)
>
> BBs seem to have a relatively wide range of acceptable torque so it seems
> like a reasonable place to start.
Not with a CF frame with a glued BB shell. You don't want to overtighten
that one.
>
> I'm still keen to know whether a BB loose enough to wear the shell threads
> would be obviously loose (creaky/wobbly). Overtightening a BB would seem to
> need an excessive amount of force.
Normally it creaks first as a warning. If you don't use a large pipe on
your wrench as a lever the chance of overtighten is small. But as I said
you have to be careful with a CF frame.
Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)
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Date: 08 May 2007 23:02:35
From: M-gineering
Subject: Re: Correct way to fit cartridge bottom brackets
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Lou Holtman wrote:
> PJay wrote:
>
>> It's strange how torque wrenches and bikes seem to polarise people,
>> when I posted about using a torque wrench lots of people told me I
>> didn't need one, when I post about not using one quite a few seem to
>> recommend that I do :-)
The problem with a torquewrench is it stops people thinking. And when
they get the torquevalue wrong they blissfully keep cranking untill
something breaks and the brain re-engages ;)
--
---
Marten Gerritsen
INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl
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Date: 08 May 2007 21:53:13
From: PJay
Subject: Re: Correct way to fit cartridge bottom brackets
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"Lou Holtman" <lholremovethis@planet.nl > wrote in message
news:4640e1f0$1@news.nb.nu...
> PJay wrote:
>
>> It's strange how torque wrenches and bikes seem to polarise people, when
>> I posted about using a torque wrench lots of people told me I didn't need
>> one, when I post about not using one quite a few seem to recommend that I
>> do :-)
>
> Yes that's strange.
>
>>
>> Cranks seem particularly dependant on accurate torquing so I'm pretty
>> sure I'll keep using one for that, the torque wrench I have that I've
>> used for BBs is pretty old and second hand so I'm a little unsure that
>> the 'feel' I might be developing using it might be off. The good quality
>> wrench I have unfortunately only measures torque for right hand threads.
>
> You bought the wrong one ;-)
>
>>
>> BBs seem to have a relatively wide range of acceptable torque so it seems
>> like a reasonable place to start.
>
> Not with a CF frame with a glued BB shell. You don't want to overtighten
> that one.
>
>>
>> I'm still keen to know whether a BB loose enough to wear the shell
>> threads would be obviously loose (creaky/wobbly). Overtightening a BB
>> would seem to need an excessive amount of force.
>
> Normally it creaks first as a warning. If you don't use a large pipe on
> your wrench as a lever the chance of overtighten is small. But as I said
> you have to be careful with a CF frame.
>
> Lou
> --
> Posted by news://news.nb.nu (http://www.nb.nu)
>
Yes I did buy the wrong wrench (I wasn't pleased) oh well. The old wrench I
have is probably good enough considering the reasonably wide torque range
for BBs (although apparently at higher levels torque can ramp up quite
quickly).
I'm sure it would all be a lot easier (and possibly cheaper) just to leave
it all to a bike shop, but I'm coming to really enjoy working on the bike
(I'd like to build one up sometime too). We've all got to learn somehow.
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Date: 08 May 2007 07:48:52
From: D'ohBoy
Subject: Re: Correct way to fit cartridge bottom brackets
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On May 7, 4:01 pm, Nate Knutson <biken...@riseup.net > wrote:
>
> With BBs in general you're not going to damage any good threads by
> overtightening, unless maybe you're being really careless with a tool
> that gives a very large amount of leverage. 70N is a LOT of torque.
> And using a torque wrench here is a pain anyway because it generally
> disallows using a skewer or axle to keep the BB tool from slipping.
> Also, of course it's important to use a good amount of grease or anti
> seize, or arguably threadlocker on plastic adaptor cups.
>
If you can find it, the Tacx bb cup tool is a simple and extremely
useful tool if you plan to pop a certain type of bb in and out
frequently. The tool fits the splines of the bb and has a spring-
loaded stud that threads into the spindle to hold the tool engaged
with the splines. Costs about $25 or so but damn well worth it. Got
the campy version myself. You will have to use a crow's foot with
your torque wrench or a large box wrench but the bb tool will NEVER
slip.
D'ohBoy
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Date: 08 May 2007 06:07:35
From: andresmuro@aol.com
Subject: Re: Correct way to fit cartridge bottom brackets
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On May 7, 1:29 pm, "PJay" <pauldavis...@hotmail.com > wrote:
> I'm trying to develop a feel for fitting cartridge bottom brackets
> (Octalink). Shimano specs. state that both the cartridge and non-driveside
> adapter should be torqued to between 50-70Nm. I have a torque wrench but
> it's pretty old and very probably inaccurate and in any event, more often
> than not when i mention torque wrenches it's suggested that I try to develop
> a 'feel' for correct tightness (not that easy when only working on your own
> bike - the BB usually only comes out twice a year for regreasing).
>
> Is it okay just to go for 'nice and tight' with both flanges up tight
> against the BB shell or do I need to be more accurate than this? I
> understand that a loose BB could damage the thread in the shell and I don't
> want to risk this. Would a BB and/or adapter that were loose enough to cause
> thread damage be obvious (creak or wobble) or is it more subtle than that?
> Is it possible damage the theads in the BB shell or the shell itself by
> overtightening?
I've been assembling and disasembling my bikes for the past 20 years.
I have never used a torque wrench on anything. I have never striped
threads. In fact, I doubt that many people strip threads with
exception of tiny aluminum bolts and nuts. Torque wrenches are
something new. AFAIK most mecahnics didn't use torque wrenches until
recently. I think that if you are a pro mechanic in a bike shop
assembling several bikes a day in a hurry, you need a torque wrench so
you can go faster w/o worrying about too much or too little torque.
however, if you are an amateur, you'll be able to handle most jobs w/o
a torque wrench.
Andres
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Date: 08 May 2007 23:19:35
From: Michael Warner
Subject: Re: Correct way to fit cartridge bottom brackets
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On 8 May 2007 06:07:35 -0700, andresmuro@aol.com wrote:
> however, if you are an amateur, you'll be able to handle most jobs w/o
> a torque wrench.
If you avoid carbon stems, seatposts, bars etc, anyway.
--
Home page: http://members.westnet.com.au/mvw
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Date: 08 May 2007 04:40:38
From: almost_fast@yahoo.com
Subject: Re: Correct way to fit cartridge bottom brackets
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On May 7, 2:29 pm, "PJay" <pauldavis...@hotmail.com > wrote:
> I'm trying to develop a feel for fitting cartridge bottom brackets
> (Octalink). Shimano specs. state that both the cartridge and non-driveside
> adapter should be torqued to between 50-70Nm. I have a torque wrench but
> it's pretty old and very probably inaccurate and in any event, more often
> than not when i mention torque wrenches it's suggested that I try to develop
> a 'feel' for correct tightness (not that easy when only working on your own
> bike - the BB usually only comes out twice a year for regreasing).
>
> Is it okay just to go for 'nice and tight' with both flanges up tight
> against the BB shell or do I need to be more accurate than this? I
> understand that a loose BB could damage the thread in the shell and I don't
> want to risk this. Would a BB and/or adapter that were loose enough to cause
> thread damage be obvious (creak or wobble) or is it more subtle than that?
> Is it possible damage the theads in the BB shell or the shell itself by
> overtightening?
What's the big deal? I just use my torque wrench. Only takes a minute
or so longer and I never worry about problems from "too tight" or "too
loose" installation.
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Date: 07 May 2007 14:01:33
From: Nate Knutson
Subject: Re: Correct way to fit cartridge bottom brackets
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On May 7, 12:29 pm, "PJay" <pauldavis...@hotmail.com > wrote:
> I'm trying to develop a feel for fitting cartridge bottom brackets
> (Octalink). Shimano specs. state that both the cartridge and non-driveside
> adapter should be torqued to between 50-70Nm. I have a torque wrench but
> it's pretty old and very probably inaccurate and in any event, more often
> than not when i mention torque wrenches it's suggested that I try to develop
> a 'feel' for correct tightness (not that easy when only working on your own
> bike - the BB usually only comes out twice a year for regreasing).
>
> Is it okay just to go for 'nice and tight' with both flanges up tight
> against the BB shell or do I need to be more accurate than this? I
> understand that a loose BB could damage the thread in the shell and I don't
> want to risk this. Would a BB and/or adapter that were loose enough to cause
> thread damage be obvious (creak or wobble) or is it more subtle than that?
> Is it possible damage the theads in the BB shell or the shell itself by
> overtightening?
With BBs in general you're not going to damage any good threads by
overtightening, unless maybe you're being really careless with a tool
that gives a very large amount of leverage. 70N is a LOT of torque.
And using a torque wrench here is a pain anyway because it generally
disallows using a skewer or axle to keep the BB tool from slipping.
Also, of course it's important to use a good amount of grease or anti
seize, or arguably threadlocker on plastic adaptor cups.
Getting the plastic Shimano cups installed tightly enough without ever
breaking any is a different story. It sort of takes some technique
IME, and there are different ways of doing it. Most people seem to
install the main unit to full torque and then the adaptor to whatever
they feel it can handle. Some other people do this thing where both
sides are installed loose and then torque is transferred from the main
unit to the plastic adaptor to tighten both simultaneously, or
something.
One consideration is that BB shells are pretty frequently in a
condition where an awful lot of extra friction is created by poor
thread alignment or contamination by paint or other stuff. When you're
torquing the BB, a certain amount of the energy you're putting into it
gets eaten up purely in overcoming this friction. It's something to be
aware of when developing your "torque feel." Sometimes a BB is just
totally nasty and starts taking a fairly large amount of torque just
to get the cartridge in; in these cases the shell really should be at
least chased if possible, but if that's not possible then you'll need
to put that much more torque into the final tightening.
I don't think you can assume it will be obvious if you're riding a
loose cup. Most of the time you'll get some warning, at least before
too long.
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Date: 08 May 2007 09:00:47
From: Peter Cole
Subject: Re: Correct way to fit cartridge bottom brackets
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Nate Knutson wrote:
>
> Getting the plastic Shimano cups installed tightly enough without ever
> breaking any is a different story. It sort of takes some technique
> IME, and there are different ways of doing it. Most people seem to
> install the main unit to full torque and then the adaptor to whatever
> they feel it can handle. Some other people do this thing where both
> sides are installed loose and then torque is transferred from the main
> unit to the plastic adaptor to tighten both simultaneously, or
> something.
It's been a while since I've done one, so I could be wrong, but I seem
to recall that the directions that came with the Shimano said to install
the plastic cup first. That seems to make sense given how weak the
plastic teeth are.
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Date: 07 May 2007 23:10:28
From: M-gineering
Subject: Re: Correct way to fit cartridge bottom brackets
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Nate Knutson wrote:
> Getting the plastic Shimano cups installed tightly enough without ever
> breaking any is a different story.
Torque for plastic cups is 40 Nm
---
Marten
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