Torque Concept versus Torque Measurement

Calvin Jones

(This is a general reply to the topic as it began.)

There are different reasons for using a torque wrench. It must be
kept in mind, however, a torque wrench is only a tool, and will not
replace thinking. What a threaded fastener (nut & bolt) needs is an
adequate amount of tension, which is simply not-too-little and
not-too-much. This can be achieved by a truing the thread either by
hand or by a torque wrench. A torque wrench is then a measuring tool,
much like a spoke tensiometer, a tape measure, a caliper, or even a
tablespoon or measuring cup for a cook. You can make a great cake by
grabbing hands full of flour and pouring out the salt, but most people
would not want to purchase such a cake at their local grocery store.
A torque wrench, used correctly, makes a good mechanic better.
However, if basic knowledge is lacking, a torque wrench will not act
as "magic wand" making every component safe and secure.

There is also a difference between working on your own bike, and
working professionally on other peoples bikes. Correct use of a
torque wrench is one more way a shop can stand fully behind its work.
A quick look at various bicycle forums will show that the creaking
bicycle is often an issue, making lack of torque knowledge wide
spread.

See also for threading and torque issues:
http://www.parktool.com/repair_help/thread.shtml

http://www.parktool.com/repair_help/torque.shtml

Werehatrack

On 8 Apr 2004 06:21:16 -0700, info@parktool.com (Calvin Jones) may
have said:

>There is also a difference between working on your own bike, and
>working professionally on other peoples bikes. Correct use of a
>torque wrench is one more way a shop can stand fully behind its work.

This is true in more areas than just bike repair. In my experience,
the automotive mechanics who didn't use a torque wrench in enough
places also tended to be the ones who had the most comebacks and
customer complaints.

I stayed out of the other thread initially because it seemed to me
that advocating the *non*-use of a torque wrench is a religious
position, and as such, there was little point in saying anything. The
wise reader would see the fallacy, and the unwise would likely only
learn by experience. However, the issue here really *is* experience,
and I eventually had to make the point (obliquely) that a torque
wrench is, in many respects, a tool to add artificial judgement to the
actions of the inexperienced...and to provide repeatable results for
the experienced in conditions of fatigue or time pressure...and to
provide *accuracy* in places where organic measurement may not be
"good enough", few that those are on a bike.

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