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Lets Talk Torque.


Caerus

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At the back of the Parktool Big Blue Book of Bicycle repair and maintenance there use to be a table listing torque settings for the different parts. Have to add that my book is 8 or 9 years old though.

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I'm sure that must cost a small fortune though. In saying that, in the box the Birzman wrench came in it says it was tested & calibrated. Let's hope it wasn't tested on a Monday or Friday :eek:

 

Just test it against a known good one - but like I say - good tool shops have torque testers that you can do a quick check on - usually free...

 

Norbar was not wildly expensive - more than a birzman, but not insanely so - compared to the cost of stripping a stud... cheap... compared to blowing up a race motor.... practically free...

 

Besides - it was less than the snap on POS....

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Pretty nifty little tool this :)

 

post-271-0-81713500-1393587124_thumb.jpg

I only saw something similar after buying the whole wrench, great for on the trail repairs :thumbup: May look at getting one anyway.
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When in doubt use 4 or 5nm...

 

Most manufacturers post the torque specs in their maintenance/specification documents - google will help you find them.

 

PS - please check your torque wrench is ACCURATE before using it - better tool shops will have a tester in house - in Jhb, The Toolshop has one.

Also remember to loosen the bolt by half a turn or so and then tighten it.
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Pretty nifty little tool this :)

 

post-271-0-81713500-1393587124_thumb.jpg

The new ones come with three or four different allen key/torque key head sizes.
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Why is that?

Smaller increments can often lead to incorrect readings. For example, it’s almost always a bad idea to take a bolt that has already been tightened to 65 ft-lbs and take it to 70. This is true, and if you find yourself in this situation, you should loosen the bolt and then retighten it to 70 ft-lbs. A bolt that has already been tightened will usually have a breaking point (the amount of pressure that’s required to get it moving again) that’s higher than the amount that it has originally been torqued. So, for a bolt that has already been tightened to 65 ft-lbs, the force required to get it moving again could be 5 ft-lbs or more on top of the original 65.

 

Read more: http://www.circletra...l#ixzz2uerRXS8q

Edited by Pusher
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Smaller increments can often lead to incorrect readings. For example, it’s almost always a bad idea to take a bolt that has already been tightened to 65 ft-lbs and take it to 70. This is true, and if you find yourself in this situation, you should loosen the bolt and then retighten it to 70 ft-lbs. A bolt that has already been tightened will usually have a breaking point (the amount of pressure that’s required to get it moving again) that’s higher than the amount that it has originally been torqued. So, for a bolt that has already been tightened to 65 ft-lbs, the force required to get it moving again could be 5 ft-lbs or more on top of the original 65.

 

Read more: http://www.circletra...l#ixzz2uerRXS8q

 

Good article but I'm not sure why you'd loosen the bolt a half turn and retighten it. If it's torqued correctly, it should be fine. Unless you want to retighten then yes.

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Good article but I'm not sure why you'd loosen the bolt a half turn and retighten it. If it's torqued correctly, it should be fine. Unless you want to retighten then yes.

I check all my pivot bolts on a monthly basis-so yes re-tightening them. Lost one or two on the trail before and can be expensive and sometimes difficult to replace.
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I check all my pivot bolts on a monthly basis-so yes re-tightening them. Lost one or two on the trail before and can be expensive and sometimes difficult to replace.

 

I use Loc-tite. The blue one that doesnt set and can be retightened.

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Good article but I'm not sure why you'd loosen the bolt a half turn and retighten it. If it's torqued correctly, it should be fine. Unless you want to retighten then yes.

 

There is an element of sticktion involved in torqueing things - BUT - the most important think to know on a torque spec is if it is given as oiled or dry.... torqueing something up to a dry spec if it is oiled/lubricated is a sure fire way to break something.... and if you do it in reverse, it will probably loosen itself quite quickly....

 

I have a table somewhere if someone is interested, I could find it, scan and post it up.

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