Torque wrench for BBs

I was wondering whether anyone might recommend a torque wrench for fitting
bottom brackets?

I believe that the cartridge body screws in from the drive side which is a
lefthand thread. The torque wrench that I have isn't reversible. Are Halford
wrenches reversible?

Also, do I really need a torque wrench for this job? Can the BB or BB shell
be damaged by being too loose? I'm pretty new to bike maintainence and no
good at guaging torque values by hand.

Thanks,
Paul

Paul Davis wrote:
I was wondering whether anyone might recommend a torque wrench for
fitting bottom brackets?

I believe that the cartridge body screws in from the drive side which
is a lefthand thread. The torque wrench that I have isn't reversible.
Are Halford wrenches reversible?

Also, do I really need a torque wrench for this job? Can the BB or BB
shell be damaged by being too loose? I'm pretty new to bike
maintainence and no good at guaging torque values by hand.


Unless you've got a very unusual cartridge BB (*), then just put it in, and
turn the spanner until it feels "fairly tight". I'd call that a moderate
push on an 8-10 inch spanner handle. Not a big heave (too tight), and not
finger tight (too loose).

You don't need a torque wrench for this job (+).


(* ie. not your usual Shimano / Campag off the shelf stuff )
(+ I've never used a torque wrench on a bicycle, inspite of owning two,
knowing how to use them and having a passing understanding of mechanical
engineering precision. I suppose there might be a use somewhere in a disc
brake assembly?) .


- Nigel


--
NC - Webmaster for http://www.2mm.org.uk/
Replies to newsgroup postings to the newsgroup please.

in message , Paul Davis
') wrote:

I was wondering whether anyone might recommend a torque wrench for
fitting bottom brackets?

I believe that the cartridge body screws in from the drive side which
is a lefthand thread. The torque wrench that I have isn't reversible.
Are Halford wrenches reversible?

Also, do I really need a torque wrench for this job? Can the BB or BB
shell be damaged by being too loose? I'm pretty new to bike
maintainence and no good at guaging torque values by hand.

You don't need a torque wrench to put a bottom bracket in, nor to do
most other jobs in bicycle maintenance. Obviously, don't overtighten
things particularly where they are threaded into aluminium. A bit of
copper grease helps when you are putting steel parts into aluminium,
just to be sure you can get it out again. But otherwise, just use
common sense.

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/
;; "If I were a Microsoft Public Relations person, I would probably
;; be sobbing on a desk right now" -- Rob Miller, editor, /.

Paul Davis wrote:

I was wondering whether anyone might recommend a torque wrench for fitting
bottom brackets?

I believe that the cartridge body screws in from the drive side which is a
lefthand thread. The torque wrench that I have isn't reversible. Are Halford
wrenches reversible?

Also, do I really need a torque wrench for this job? Can the BB or BB shell
be damaged by being too loose? I'm pretty new to bike maintainence and no
good at guaging torque values by hand.

Just screw it in until it stops!

in message , Getronics Wang
') wrote:


"Zog The Undeniable" wrote in message
news:4116447e.0@entanet...

Just screw it in until it stops!

Problem is you really should tighten the cranks back on with a torque
wrench or you could have problems in a short while, clicking etc
resulting in wear.

You must be extraordinarily heavy handed with a spanner. I've never used
a torque wrench on a bike in my life, and never had any problems of the
sort.

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/

'graveyards are full of indispensable people'

"Zog The Undeniable" wrote in message
news:4116447e.0@entanet...
Paul Davis wrote:

I was wondering whether anyone might recommend a torque wrench for
fitting
bottom brackets?

I believe that the cartridge body screws in from the drive side which is
a
lefthand thread. The torque wrench that I have isn't reversible. Are
Halford
wrenches reversible?

Also, do I really need a torque wrench for this job? Can the BB or BB
shell
be damaged by being too loose? I'm pretty new to bike maintainence and
no
good at guaging torque values by hand.

Just screw it in until it stops!

Problem is you really should tighten the cranks back on with a torque wrench
or you could have problems in a short while, clicking etc resulting in wear.

KC

Simon Brooke wrote:
in message , Getronics Wang
') wrote:

Problem is you really should tighten the cranks back on with a torque
wrench or you could have problems in a short while, clicking etc
resulting in wear.

You must be extraordinarily heavy handed with a spanner. I've never
used a torque wrench on a bike in my life, and never had any problems
of the sort.

Or light handed, I guess KC might have meant.

It's perfectly reasonable to use a torque wrench for this particular job
unless one is already experienced enough to know when the cranks are
pushed on far enough by feel (or measuring?).

~PB

"Simon Brooke" wrote in message
...
in message , Getronics Wang
') wrote:


"Zog The Undeniable" wrote in message
news:4116447e.0@entanet...

Just screw it in until it stops!

Problem is you really should tighten the cranks back on with a torque
wrench or you could have problems in a short while, clicking etc
resulting in wear.

You must be extraordinarily heavy handed with a spanner. I've never used
a torque wrench on a bike in my life, and never had any problems of the
sort.

Likelihood is of under tightened crank bolts. Stripped threads are possible
if torque wrench settings are exceeded. Few people have a calibrated
forearm.
Crank bolts are the only place on a bike I see the need for a torque wrench.

KC

Unless you've got a very unusual cartridge BB (*), then just put it in, and
turn the spanner until it feels "fairly tight". I'd call that a moderate
push on an 8-10 inch spanner handle. Not a big heave (too tight), and not
finger tight (too loose).

I'd say that your vague description is a fairly good argument in
favour of the precision of a torque wrench. Especially since I don't
think that the correct figure of around 500 in-lb for a cartridge BB
(sorry, don't remember the Nm multiplier) equates to 50lb on a 10"
spanner, which I would not describe as "fairly tight" or "moderate"
(but maybe I am just feeble).

I always use torque wrenches (Park PW-3 & PW-4, sadly no longer
available) when working on my bikes. I am often surprised at how much
tighter or looser the manufacturers' recommended settings are than I
would have chosen by instinct alone.

--
Peter Headland

You don't need a torque wrench to put a bottom bracket in, nor to do
most other jobs in bicycle maintenance. Obviously, don't overtighten
things particularly where they are threaded into aluminium. A bit of
copper grease helps when you are putting steel parts into aluminium,
just to be sure you can get it out again. But otherwise, just use
common sense.

Cobblers! After much practice (and with probably some innate
aptitude), you have developed a "feel" for this. You choose to forget
all of that and describe your acquired skill as as "common sense"?

I'll bet that, if we checked your bikes, we would find you are well
outside the manufacturer's recommended torque on any number of the
fasteners to which you have applied your magical common sense.
Fortunately, these things tend to have a wide safety margin.

The OP claims to have no feel for judging these things. I don't call
it "common sense" to perform safety-critical work on a bicycle (not
the BB, but stuff like brake cable pinch bolts) if you have no feel
for too loose (so the cable slips and you lose your brakes at a
critical moment) or too tight (so the thread strips or the bolt breaks
and you lose your brakes at a critical moment).

--
Peter Headland