To the Point: Torque Specifications

Mar 5, 2013 at 0:09
Mar 5, 2013
by Mike Kazimer  
 
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As carbon fiber becomes increasingly common in the mountain bike world, and components get lighter and lighter, it's more important than ever to ensure bolts are tightened to the proper torque spec. Simply tightening a bolt until it's "snug" isn't enough - under or over-tightening can lead to damaged components or rider injury. We asked Jay Seiter, an R&D engineer at Pedro's North America, to fill us in on the basics of torque spec and proper torque wrench usage.




What is torque? How is it measured?

In simple terms, torque is a twisting force that is likely to cause an item to rotate.Torque
is calculated as force multiplied by length with the length being the distance between the
rotational axis and the point where the force is applied. Torque is measured most commonly
as Newton meter (Nm), pound-inch (lb-in), or pound-foot (lb-ft) units. The last two are common
in the U.S. but are often referred to as inch pounds and foot pounds. Newton meters are
standard on most bicycle components. As it relates to bicycle mechanics, torque is most
often related to component fasteners. These fasteners are threaded, which converts the torque
into a linear force used to hold components in place or to provide a clamping force to hold two
components together. A common example of this is the interface between a stem and handlebar.



Torque is calculated by multiplying the amount of force (F) by the length (L) of the lever.



Why is knowing the proper torque spec important for bicycle components? What happens if you over-tighten a bolt?

As a human powered vehicle, the weight of a bicycle is a major contributor to performance. This
requires engineers to push the limits of each material and design they choose. The engineer must
factor in material properties, part shape, riding conditions, product life, and more. The torque
specification provided with a bicycle or component makes sure the forces applied to these parts
are within the intended limits. If the torque is too low, a component is likely to slip or fall off. Conversely,
if the torque is too high, the component or fasteners may be over-stressed and fail. In either case,
significant injury could result. While torque specifications are important with all type of materials,
the growing number of carbon fiber components has led to an increasing focus on torque and the use
of torque wrenches. While carbon fiber allows for more optimal design and provides a far higher strength
to weight ratio compared to steel and aluminum, it is also more susceptible to crushing and cracking
when improperly set up. Simply put, the margin for error is much smaller. For this reason, using a
torque wrench has become essential.


A click type torque wrench, one of the three most common types of torque wrench.


How does a torque wrench work? Are there different types?

The general principle of a torque wrench is that as torque is applied to a fastener, the
torque wrench uses a calibrated mechanism to display the torque applied or otherwise
indicate when a specified torque has been reached. The three most common types of
torque wrenches are beam type, click type, and digital. A beam type torque wrench
uses two parallel rods, one being the wrench handle, and the second having a torque
display scale. The handle rod is designed to bend as torque is applied to the fastener.
The torque display scale remains unbent allowing the relative angle between each rod
to indicate the torque. These are the least expensive and simple type of torque wrench,
but rely on the user to constantly look at the torque scale. This may be challenging in
some bicycle applications where wrench positioning is limited.

A click type torque wrench is the most common type offered in the cycling industry.
This type of torque wrench uses a calibrated clutch mechanism and connected pivoting
head to indicate when a preset torque has been reached. When the torque setting is
reached, the head displaces slightly and makes a clicking noise as a result. Click type
torque wrenches are available in fixed setting, specific to a single torque value, and
adjustable setting, which can be set to a range of torque values. Pedro’s Demi Torque
Wrench and Pro Torque Wrench are click type wrenches adjustable from 3 Nm to 15 Nm
and 6 Nm to 30 Nm respectively. We chose to offer this type of torque wrench because
we felt it was the best blend of accuracy, ease of use, ease of calibration, and value. A
digital torque wrench uses a strain gauge attached to a torsion rod to measure torque and
convert it into the common torque units using a processor. The digital torque wrenches work
on similar principles as a beam type torque wrench, but are more advanced, displaying the
torque value digitally as the fastener is tightened. In addition, many digital torque wrenches
sounds a digital alarm when a preset torque value is reached. These types are the most
expensive.


What is the proper technique for using a torque wrench?

The technique for using each type of torque wrench varies, but the general principles are the
same. First, read any technical documents provided to determine torque specification and
thread treatment indicated by the manufacturer. Second, set your torque wrench to the specified
torque and double check the torque units. There is a huge difference between 10 inch pounds
and 10 foot pounds! A handy trick, though a bit finicky, is that Google search will do unit
conversions for you. Try it out by entering “5 newton meters in pound inches” and see what
you get. Worst case, you’ll find many free conversion tools. Third, apply treatment, such as
grease or threadlock, to the fastener threads if required by the manufacturer. Fourth, while
holding the torque wrench by its handle, begin tightening the fastener. When the correct torque
is reached, as indicated by the torque scale on a beam type, or by the click/alert on click or
digital types, stop tightening the fastener. Do not continue to tighten the fastener. This is
especially important on click/digital types as continuing beyond the set torque can damage
the torque wrench.

These four steps will cover the basics of using a torque wrench. When tightening components
using multiple fasteners, as commonly found on stems, it is very important to tighten them
using an alternating method, tightening half a turn or less before moving back to the other
fastener, and repeating this until both are tightened to the specified torque. This is important
because when one fastener is tightened, it loosens the others. Using a torque wrench, each
fastener should be tightened to the torque specification, and then re-checked for torque after
the other fasteners are tightened, repeating for each fastener until all meet the specified torque.
Just as important, this alternating method should be using when removing torque specific
hardware as well because when one bolt is loosened, the other is tightened which can lead
to thread damage. If there are four or more fasteners, they should be tightened in a crossing
pattern by moving to the fastener opposite to the one just tightened whenever possible. This is
the same technique used for tightening lug nuts on a car wheel ensuring equal tension on all
fasteners.

Stem bolts, crank bolts, even lock-on grips should be tightened to the proper torque spec to avoid damaging components.


What about storage? Does a torque wrench need to be at a certain setting before putting it away?

As a calibrated device, all torque wrenches should be used with care and stored in a protective case. For
adjustable click type torque wrenches, the wrench should be set to its lowest torque setting or approximately
20% of the maximum torque. For example, the Pedro’s Demi Torque should be set to 3 Nm for storage as this
is 20% of the maximum torque of 15 Nm. If the wrench has be unused for a long period of time, set the wrench
to 50% of the maximum torque and operate the click mechanism five to ten times before using the wrench on
a fastener. This is also suggested before the first use of a new torque wrench.


How often does a torque wrench need to be calibrated? How is this done?

Calibration is most important for click type torque wrenches. The exact process varies from wrench to
wrench but the process typically involves adjusting preload on a calibrated spring inside the wrench.
The wrench is then checked against a device with a known and calibrated torque. We suggest having
Pedro’s torque wrenches be calibrated every three to six months with heavy (daily) usage. The occasional
user could likely wait longer if the wrench is treated well and hasn’t been dropped or abused. We also
strongly recommend wrench owners work with a professional calibration service to ensure the proper
equipment and techniques are employed. We have had good luck with ESSCO Lab located in
Massachusetts but any similar calibration service should be able to provide calibration or at very
least determine if the wrench is calibrated within tolerance.


Occasionally, you'll hear someone say “I don't need to use a torque wrench – I can just tell when it's tight enough." Any thoughts on this statement?

Most mechanics are guilty of not using a torque wrench at least some of the time. However,
bicycles and riding itself have changed considerably in a very short time. Considering the
variables of fastener material, multiple fastener clamps, component material, wrench size,
thread treatment, component design, etc., there is simply no way to get a torque specification
correct by feel. Many mechanics still disagree, arguing that their years of experience have
given them the "feel" needed to properly torque hardware, but test after test has shown this
is rarely true.


www.pedros.com
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141 Comments

  • + 155
 Torque wrench...a little spendy, so I guess I'll default to "living life on the edge".
  • + 55
 Hand tightening got us this far!
  • + 210
 Every time I tighten up a lock on grip with no torque wrench, I get an intense rush of adreneline.
  • + 14
 Check your local hardware stores, they come on sale once in a while... You don't need an uber expensive digital laser aligning titanium coated with diamond incrusted handle wrench. Just get something like this:

attach.kawiforums.com/2007/09/08/20070908124551-0-1940.jpg
  • - 21
flag velociraptor-clintthrust (Mar 5, 2013 at 5:26) (Below Threshold)
 If you don't use a torque wrench, Bruce willis WILL come in a blackhawk and you WILL be destroyed
  • + 1
 Don't get a beam one they r crap, get a click type torque wrench off amazon, I got one for $30 with free shipping, seems pretty well built and durable, even came with a case, works jus fine, adjustable from 5-80 ft lbs
  • + 2
 darkstar63 - it is a pretty awesome buzz innit... although with lock-ons I gotta admit I am always relieved when they tighten up nicely cos those little bolts round so easily... even being careful I would bet I am still over-tightening them.
  • + 10
 While torque wrenches are good, sometimes torque specs are wrong, and if you assume it's enough it can even be dangerous.

I tightened a carbon stem to carbon bar with the recommended torque specs, and the bar slipped during the first ride. Sometimes carbon has a break in-adjustment also, so don't assume it's tight or will stay tight.

The article failed to mention break in adjustments, failed to mention the importance of friction cream when tightening carbon to carbon, and
failed to mention the value of anti-seize in some tightening situations.

The article went into detail about how to tighten a face plate on a stem but forgot one important detail that's is sometimes overlooked: make sure the gap between the face plate and the stem is equal on both sides or you can damage your threads, crack the face plate (Thompsen!), or not provide even clamping force.
  • + 11
 psyickphuk, I love when you get them so tight they let out a "squawk" when the dry bolt head and the aluminum make sweet love.
  • + 5
 On a serious note. You do have to snug up lock on grip bolts pretty damn tight, especially on a bar that is not shot peened. Im sure exceeding the recommended torque. I always make sure the bolts are not totally dry, I don't grease them per se, but rather just coat my ninger tips with a bit of grease and then rub that on the bolt heads, so that they dont get seized. I snug those little bastards right down and I have never had one break. I had one get stuck and strip out, but That was a very tired (and rusty) collar.

There are other fasteners on my bike (especially my DH bike) that I exceed spec on, but I will not divulge that info because I don't endorse it. Over time you just learn what needs to be set to "good and tight" spec. Wink
  • + 4
 Mmmmm the smell of two metals making love.
  • + 2
 lol for sure, or that horrible crack sound when you undo a set that haven't been touched in ages...

My rule is to be real careful on grips, cranks, stems, fork crowns etc - anything you need to leave a gap basically. Whereas something like a shock or pivot bolt with a nut on I tighten as much as possible (within reason).
  • + 13
 Carbon frame: $2500.

Pedros Pro Torque Wrench: $102 (on sale on jensonusa.com)

Cracking carbon frame because you're too cheap to spend an extra 4% so you can properly torque your bike: PRICELESS!
  • + 12
 anyone in the US should just go to Harbor Freight and get one on the cheap
  • + 1
 I've been wondering this do most people use a torque wrench on their bikes? Im curious because I'm getting a bike in April and was planning in buying a nice one, but if its not 100% necessary then I might forgo that for a bit.
  • + 1
 No, most people don't, they're not really necessary just nice to have. Most bolt problems come from rounding them off not over-tightening - get yourself a quality set of allen keys.
  • + 1
 PS: unless your bike/bits are carbon... which was what this article highlighted really.
  • + 6
 If you have anything carbon that is clamped on with bolts (frame, seatpost, handlebar, stem) you really should own a torque wrench.
  • + 12
 I also think if you can afford to buy carbon, you can afford to buy a torque wrench.
  • + 9
 I didn't have a torque wrench for years, never encountered any real "issues". Invested in a Park Tool click type, think I paid around $70-80 on eBay. Now, every time I take something off, upon re installation I always use my torque wrench. Kind of surprising how tight some parts need to be, and how "un" tight some other parts need to be. I figure in the long run my parts will atleast last longer. I have noticed that the amount of noise, creaks, etc my bike makes has greatly decreased. I will always use one from now on, can be used for many other things besides my bike so its kind of a no brainer if you are big DIY/tinkerer like myself.
  • + 0
 Just spoke to my LBS after reading this and told them i was looking for a torque wrench. His response was 'i never used to see any broke bolts or parts from overtightening until people started buying torque wrenches..i mean im not trying to talk you out the sale.." I said "i dont need one then?" he said "just use common sense" Big Grin ...for these reasons i do not have a new torque wrench in my toolbox tonight. Im still wondering whether i need one or not..
  • + 4
 Sorry Pabail, but I'm questioning the competence of your LBS... Many people can use common sense and be just fine, but "'i never used to see any broke bolts or parts from overtightening until people started buying torque wrenches.." doesn't make any sense whatsoever.
  • + 2
 dirtworks911...it didnt make sense to me either. I think i would like to use one for my suspension bolts (to save the bearings) and my stem (as i snapped a bolt in my Hope Fr Stem by overtightening it). The point of my post is that it was a strange conversation and an unexpected recommendation from them. Before i spoke to them i think i half expected them to sell me the most expensive torque wrench in whatever range they had there.
  • + 1
 I can somewhat see this happening. Torque wrenches need to taken care of properly. When they are not returned to the suggested setting for storage, if they get dropped or bounce around in a tool box or anything it will greatly increase the range of its accuracy. I've seen a el cheapo torque wrench brand new out of box that was almost 20% out of spec, and ive seen a 10year old quality torque wrench still within 4% accuracy.I know when one of my torque wrenches got dropped off a piece of equipment I had it checked and it went from being 4% to 8% accuracy, and that was only one drop.
  • + 2
 hey protour- not all stems should have even space. easton ea50 is just one that requires one side torqued down first. READ INSTRUCTIONS!!! some avid brake are this was as well.
  • + 1
 @dirtworks911: I think the issue could well be cheap wrenches (as they are a bit expensive), and this calibration drama, c'mon, we know thats not gonna happen every 3-6months unless your a proud mechanic.
And if its not calibrated its useless.

Also the thing about "the feel" not accurate but our body can be trained to recognize and measure forces, like knowing what 100g in weight feels like. Given its a set force it doesn't matter what materials its being applied to so long as the proper technique is used (greasing threads etc).
  • + 1
 @houireedi: Avid brake clamps > terrible cheapy things.
  • + 26
 Great info for the masses, but I would like to add that there is a large amount of friction torque applied to dry installed hardware. Especially the underside square edge shoulder of bolts heads, after nearly 20yrs of installing precision hardware I strongly recommend cleaning all threads properly, on both male and female sections with alcohol then apply desired loctite application number on engagement threads and a very small amount of grease on underside shoulder which sometimes combines a washer. Using this technique is critical for proper torque settings . Apllied torque and friction torque are two different scenarios .
  • + 19
 Lubrication of the threads can make all the difference in the world... a dutch wheelbuilder did a test by torquing a bolt to 5NM dry and lubricated, and the difference is staggering: www.bikeboosting.nl/content/images/2_3847_LRb3mPHuZh-576x.jpg
  • + 7
 Also paying attention to threads, clean threads, dusty treads with a tiny bit of grime or oxydation or left over loctite. Using oily air from a rotten compressor to blow clean threads. All can get false torque readings or render loctite inoperable. Also WD40 is so wrong for everything and anything.

Bikes should be assembled and maintained under clean room condition 5 with full dustsuit and breathing mask;-)
  • - 3
 why wd-40 is wrong?
  • + 6
 WD-40 is not a lubricant , its a water disperser , the only thing I use it for is spraying the HT leads and connections in my clapped out cars to get the moisture out of the electrical parts and protect it from rusting.
  • + 8
 WD 40 is the most misused and abused product I know. Like bigburd said, clapped out cars are about the only application (even then there is usually a better product for the task at hand). I have not bought a can of that stuff in years, it should never be used for cleaning or maintaining bicycles.
  • + 1
 Torque wrenches definitely have their uses, when I first changed the oil filter in my motorbike I found the previous owner had over tightened the bolt and stripped the inside of the crank case. Worst ever.
  • + 2
 If you want to get real picky; wet torque (lubricated bolts) differs from dry torque. By how much, your guess is as good as mine but its enough for car manufacturers to have specs on this.
  • + 4
 I love it (actually I hate it) when I'm doing a tune-up on a crappy bike and you can smell WD 40 in the hubs and BB, like the owner thought he could just spray a bunch in there and it would magically fix his bearings.
  • + 5
 WD 40 should not go near bikes? Someone tell Chris King they've been recommending the wrong product to clean their hub bearings and headset bearings.
  • + 3
 It's fine for using as a degreaser/cleaner , though not ideal , but it should NEVER be used to lubricate moving parts , only if the parts are seized together , then you would use the WD40 , clean all residues of it away and grease/lube properly.

And if chris king actually knows what they are talking about then they would also recommend that you never use it for lubricating anything ...Especially bearings of all things.
  • + 5
 Yes, WD40 should not be used for lubrication - but should never be used for cleaning? Bollocks!

Nothing wrong with a good squirt of WD40 to clean the shit off bolts & threads, wipe off the excess, then stick some grease on.
  • + 3
 Yes but the problem is alot of riders use it as a lubricant , which is the point we are trying to make.
If some one is stupid enough to use it as a lube then I doubt they are smart enough to use it for cleaning/degreasing.
  • + 1
 WD can be used to clean bearings so long as you get all of it out. I just think there are better cleaners/degreasers to use..... I hate how it smells too.... lol
  • + 0
 I just use white spirit to clean my bearings , it evaporates fast so there is no residue left behind , just make sure you get grease in there fast other wise rust will set-in very quickly.
  • + 1
 I use parts cleaner, blow it out with an air gun then re-pack.
  • + 1
 I like the smell see, maybe that's why I use it.. you're right though it is not a good degreaser - it leaves lots of residue. For bearings etc I would probably use 99% isopropanol, it is good stuff & evaporates very fast.

Sometimes, rather than a proper clean, I give my whole bike the once over with WD40 & a rag - the equivalent of a whore's bath if you like Smile
  • + 1
 @ psyickphuk, "whore's bath" lol

I think you may have discovered another proper use of WD40....
  • + 1
 after a major wet ride or a wash down i spray wd down my seat tube of my cromo frame then flip it over to drain it all out to prevent rusting. Try not to soak it too much as it will get in the bb, that y i flip it over
  • + 1
 The name WD-40 came from Water Displacement, 40 gallons... it was what was written on the drums used by NASA. The stuff is petroleum based and essentially similar to mineral spirits. It displaces water and other lubricants when sprayed onto the surfaces that you're cleaning. It can also be used as a penetrating oil to free stuck bolts though products like liquid wrench are far superior to it in that sort of application. It will also LUBRICATE dry applications (like door hinges and lock tumblers) somewhat but it should never be used as a chain lube, on bushings and bearings under load (especially not delrin bushings in shock linkages), or anyplace you're going to get repeated exposure to water/moisture.
  • + 3
 Why is it fasionable to slate wd-40 as a product for bicycles?

If used for its proper function e.g, as a penetrant for seized fastenings and a water dispursant fro smaller mechanical assemblies then why shouldent it be used in a bike workshop? Im a bike mechanic and it sits proudly on the shelf besides gt-85 and a pot of cv grease.

The industry needs more mechanics and not just part fitters talking the talk....
  • + 1
 I don't like WD-40. Yes, it can be used for certain aspect's of bicycle maintence. I choose not to use it as there are better penetrating oils out there and that's about it's only use imo. It is often used as a lubricant by many, many people and I think that's where distaste for it comes from. I think some of the "fashion" in not using it stems from the fact that everbody and their mother has a can in the garage somewhere .... Im not a fashion victim, I just think the stuff is misused and over-rated.
  • + 1
 I have heard peoples bearings that use WD40 to lube , thats where my distaste for it stems from . Nothing to do with fashion. I have seen people use it every weekend to ' fix ' their bearings , not realizing 1 strip down and grease repack would leave it sorted for months on end.
  • + 8
 I use it as Wasp Displacement - 40 cm... which is about how far the flame shoots when you light the spray coming out of the red straw on the nozzel and you go to incinerate a wasp nest.
  • + 1
 @deeeight

sorry for the slight correction on the naming of the product

"WD-40" (water displacer - 40) was named because it was the 40th formulation the company (Rocket Chemical Company) tried before their founder / chemist Mr Larsen found the correct formulation for their application (preventing corrosion in Atlas rocket boosters)

Its a fantastic product for the right application, but I would not use it near any bicycle...
  • + 8
 I use it on my rotors n' pads cause brakes only slow u down
  • + 1
 WD-40 is the best for killing flying insects and way cheaper than bug spray
  • + 1
 the only use I have for WD40 is lubing up my shovel when I slide pack...I go through cases of the stuff
  • + 2
 I'm sure I heard a rumor that people use it for spraying on fishing bait ? Sounds daft to me but I'm sure I have heard it mentions a few times
  • + 14
 oh no not my grips
  • + 4
 If you're running carbon bars, a torque wrench for the lock on bolts is essential. The same with any one carbon components.
  • + 2
 The grub screw is also super weak and you'll round it off too easily...
  • + 8
 If you are running carbon, you NEED to do this, that's why I always say carbon ISN'T for the masses.
  • + 4
 my hand is my torque wrench
  • + 2
 ^and also your girlfriend. LOL. I'm just kidding, you left that one wide open...
  • + 1
 I was gonna say he' s a typical yank...
  • + 9
 So many people here are never working on my bike!! EVER
  • + 4
 Park tool has torque value list on their page. www.parktool.com/blog/repair-help/torque-specifications-and-concepts

For those working in a bike shop: it is always nice when a piece breaks when using a torque wrench. Had a crank arm snap near the bolt at 8Nm that was rated at 12-14Nm. Called to warranty without hesitation. Company claimed they had never heard of that happening before, but you cannot argue with the torque wrench.
  • + 5
 As a mechanic I use a torque wrench mostly for liability reasons. If I use proper torque on every bolt and something fails down the line, none of it can blow back on me or the store.
  • + 4
 some further tips for using torque wrenches:

1. for home use, calibration of your tool is not critical (you won't be using it enough). in a pro bike workshop you need to keep a log of typical usage patterns (or even just when you bought the tool!) as torque wrenches will drift off calibration when used daily, for weeks / months

2. when setting a torque wrench, always take the value slightly above the intended value, and then back it down the intended value. many fail to do this, and get a false reading.

Doing this sets the torque more accurately. As an example, if you want to torque a bolt to 10nm, take the tool to 12-15nm and then back down to 10nm. If you just take it straight to 10nm, you can actually read this as 7-8nm with a bolt torque measurement tool.

3. always back the torque off when storing the tool. Nothing annoys a pro mechanic more than people leaving his / her torque wrenches set at high values, as it stretches the spring out and causes premature drift of calibration

4. NEVER use a torque wrench to loosen a bolt. Some torque wrenches have a reverse switch to allow left / right handed thread torque setting, but mechanics will abuse this (because they don't have to pick up another tool) and use the wrench to loosen a torqued bolt.

you should always use an allen key or torx to loosen a bolt, as you don't know how tight the torque is on this item, and using a torque wrench to loosen stubborn bolts is a sure fire way to stretch to spring

5. if you drop a torque wrench on a hard surface (concrete floor or steel base of a work stand) do not trust the torque calibration. dropping it onto a rubber floor mat won't do much harm
  • + 2
 Cheers mate! #2, #3 & #6 are especially useful.
  • + 3
 6. be aware that using different substances to clean / lubricate the threads of bolts will give wildly different torque settings to what your tool is telling you.

too much grease under the 'head' or washer or a bolt being torqued will give a false reading. Ideally you want the substance on the bolt threads and none under the head.

personally I prefer cleaning using ISO alcohol and prepping with shimano anti-seize because it eliminates creaks, prevents seizure, I was taught "grease is only for bearings, everything else uses anti-seize or loctite"

anti-seize does not affect torque values in the same way that grease or lubricants can. I would only use blue loctite for vibration sensitive applications (I have found loctite tends to dry / crack over time causing creaks): www.bike24.com/i/p/4/4/8744_00_d.jpg
  • + 1
 I have 4 torque wrenches, some for finite work and some for major torque, used when I used to be a mechanic. I admit that I do not torque everything. I guess it just depends on what it is. I do know that I have had to repair / remove more broken bolts than I care to admit due to over torque or fused metals. I am an avid believer in thread lubrication ranging from grease to anti-seize or friction paste. and adding any lubricate and drastically change your torque setting. It has even been said that in a chrome plated fastener the chrome acts as a lubricant. Something to keep in mind when hand tightening something.
  • + 1
 An alternative I have found is to use as less leverage as possible when adjusting my bike. Also adjusting opposite screws at a time is better, making all the pieces work togheter rather than tightening to the top each screw before continuing to the next one.
  • + 1
 Least leverage as possible? So I should cut all my allen wrenches in half?
  • + 1
 It would work haha
  • + 1
 try using the individual wrenches from the shortest side for leverage
  • + 1
 I think the single biggest hindrance to people using a torque wrench is not knowing what to torque things too. Its a huge pain in the ass (especially if you are working in a shop trying to pump out repairs) to have to go online and get a manual and look up the torque spec on stuff. I know that there are general guidelines but that too is iffy to go off of (what if its a 2 bolt stem face plate instead of a 4, or its a carbon face plate, etc.) That's why i love it when the components have it written right on them what the torque spec should be. It makes it a no brainer. The time invested in looking at the spec on the component, grabbing the torque wrench and properly adjusting it is minimal as opposed to getting online and searching for it. In fact, why the hell isn't printing it on the components required? If it really is as important as the article suggests, then make it an industry standard.
  • + 1
 I don't find beam type torque wrenches challenging at all. And they are calibration-free, something that always adds some level of doubt on click type torque wrenches performance.

I think that every bolt with a max torque indication should add "don't let other people do it" after the number.
  • + 1
 Excellent article! Above all do not mistreat your torque wrench. I cringe when I see people tossing them on the ground, use them as a hammer or lever, loosen fasteners with them or not return them to a default low setting to maintain long term accuracy. For my aluminum block engine cars they are mandatory. The same holds true for carbon bicycle parts and other components including bottom brackets, crank arms, cassettes, stems, brake rotors, shoe cleats...
  • + 1
 Article seems to fail at mentioning bolt stretch. On many components, once the pieces have been locked against each other, what you're reading on the torque wrench is largely the stretch of the bolt based on the frictioin at the threads (making this up as I go, lol) This is why an experienced mechanic can torque by feel. Because you can feel the stretch of the bolt. Every bolt has a yield strength and a stretch measurement that yields accurate results.
  • + 1
 I recently invested in a decent torque wrench and haven't looked back. I can't believe what I was over-tightening; I'd hate to have a bolt or bracket snap due to too much tension. Plus, I've used it on other applications (mostly automotive), and in a pinch it's heavy enough to use as a light hammer for those stubborn pivots, carriage bolts, etc.!
  • + 1
 Smacking things with your torque wrench you invested in...

*seems legit*
  • + 1
 Also, most manufacturers will void warranties if a torque wrench isn't used. Stem bolts, crank bolts, suspension linkage, anything carbon, seat clamps, axle bolts. It's seriously not worth the argument, especially with a customer over something breaking if you used a torque wrench.
  • + 2
 From a legal standpoint, ( if you work in a shop) If failure of any part or component due to improper torque
or not using a torque wrench, results in an injury, you leave yourself wide open to a negligence lawsuit. The legal system looks to assign blame in order to receive compensation. Don't give them a reason to look in your direction over something so simple as using the right tool for the job.
  • + 1
 @warrtenmtb

^^ that's about it really.

EVERY single bolt we torque on our customer's bikes is set with a torque wrench to the correct torque

our PDI sheets (pre-delivery sheets) even have records of this information

if a component fails, we can assume rider abuse or component failure, rather than a mechanic forgetting to torque a bolt correctly

I am still shocked at the number of bike stores in the UK (both chain stores and independants) who actually have torque wrenches but the mechanics cannot be bothered to use them Frown
  • + 1
 The only times I've ever really needed one was doing up head bolts on a motor and various other pressure related mechanisms... But if you can afford to keep one in your kit, then it's certainly not a bad thing! Interestingly, I recall following the recommended torque on a crank bolt.... I won't say that I can tell by feel how many Nm's I'm putting on a bolt, but the recommended amount was nowhere near enough....
  • + 3
 I use a "cheap" torque wrench for my slx cranks and various other parts, and never had a problem with stuff coming loose.

The only issue is the range of torque settings on a bike means you typically need two wrenches to cover everything.

This is my low torque wrench:
www.torpedo7.com.au/products/T7TOWN0WS/title/torpedo7-1-4-inch-drive-torque-wrench-set
Looks remarkably similar to the pedro, rebrand or cheap chinese knockoff?
  • + 2
 @si618

^^ your torque wrench is a common item produced in China, and sold under many "brand names" all over the Globe including "Pedro's"

we have the same item branded as this in the UK: www.roadcyclinguk.com/news/images/pro_torqwrench_1_hi.jpg
  • + 1
 Thanks for the info, a rebrand is fine by me and for ~$50AUD it seems to do the job pretty well.
  • + 4
 Just torque it to spec, then double it! Lol jk
  • + 1
 I will say that sometimes, the torque spec is wrong, though: I bought a a torque wrench for one of the first things on bikes that started listing a spec: brake rotors. One guess on when I lost a rotor bolt...
  • + 1
 Same thing happened to me, almost couldn't get the threaded part of the bolt out of my hub, had to very carefully drill it out, being sure to not completely ruin my hub , it was pretty scary..
  • + 4
 Tighten until it strips then back it off a quarter turn. Done.
  • + 1
 I live by my TW.

I just wanted to add this. My permanent reminder to make sure everything is tightened to the correct value!

www.pinkbike.com/photo/9283347
  • + 1
 I get so many people come to me with rounded bolts and to be fair ones coming loose too... Easy to sort.. Get a torque wrench and torque them bolts up Smile
  • + 1
 after bending my brake lever blades in a crash i have taken to torquing the brake mounts correctly to allow them to move in a crash and perhaps save bending the levers
  • + 9
 Most people just tighten them enough so when you bang it with your hand it moves.
  • + 1
 true
  • + 1
 amazing how many people don't know and crank 'em down, though
  • + 2
 I run teflon tape under mine (old moto trick). This means you can tighten them more so there is less movement of the body when you squeeze the brakes, less chance of the bolt backing out, but they will still slip in a crash.
  • + 1
 I might give that a shot.
  • + 1
 There are two thicknesses of tape. One is the pink gasfitter's tap, the other is the very very thin white plumbers tape. Go for the thicker stuff - it is easier to handle. I picked up my tape in the USA at some well-known auto-parts store. It came in blue or pink. I think it is 0.2mm.
  • + 1
 Wow another good informative article good job pb and pedros! Ill admit I only torque down my dorado clamps, crowns and crank bolts and derailur bolt...
  • - 1
 How about some real specs?

(All in in/LBS 'Murica)
Derailleur Hanger Bolts 30-45
Rear Derailleur 70-86
Handlebar Binder Bolt 150-180
Stem Binder Bolt 175-260
Seatpost Binder Bolt 150-180
Saddle Clamp Bolts 175-250
Seatpost Binder Bolt 150-180
center lock rotors 350 in /lbs
disc calipers 60in/lbs
Chainring Bolts 88-132
crank holding 106-122 in/lbs
left crank 106-122 in/lbs
bb cups 305-435 in/lbs
Through axle bolts 125-130 in/lbs
Shock bolts 85-95 in/lbs
Pivot Bolts 125-150
Alum shoulder bolts 135-150
  • - 1
 If I was a bike mechanic, for sure I would torque everything to specs and whatnot, but when you ride (sometimes aggresively, or diversely) enough that you change or adjust parts daily it's kind of hard to have the patience to tourque evything. My motto,( and call me crazy for it) currently is loose is better, I can always tighten loose, but if it gets too tight and snaps, game over. Also I usually carry a decent sized tool collection with me everywhere my bikes go. I can't help it, I'm a creature of habit. Anyways, enough about this hooplah, time to get ready to ride.
  • + 1
 Riding something too loose will shake it around and can still cause enough damage to snap/detach it. Stem faceplates snapping off due to play = game over too.
  • + 1
 Well, I don't mean like loose as a hotdog in a hallway, but I usually snug bolts then give them about a 1/4 turn then from there I go 1/4 turns until I am satisfied. I probably sound like an idiot, but it's my bike, if I break it... I've already bought it.
  • - 1
 I have carbon bars and don't use a torx. Use commen sence and feel . I have seen guys rip threads on stems all because the are very heavy handed and don't understand how to feel when it's done
  • + 26
 well you would only use a torx if your stem or grips used torx bolts. a torque wrench on the other hand is something you probably should be using if you dont know the difference between a type of bolt and a type of tool..
  • + 3
 @superbikes

something to understand about Carbon Fibre (whether bars, stem, seatpost, cranks, frame, etc.) is that carbon fibre does not have elasticity like cromoly steel, titanium or aluminium alloy

each of the metal alloys I mentioned have a feedback mechanism in that the structure actually has elasticity, you can feel this when you start loading torque on a fixing, with a hex wrench or allen key

with CF, you get no warning as there is no elasticity (no local deformation), its very easy to take the torque slightly too high and the CF will suddenly fail with a load pop / crack

we always use torque wrenches and fibre grip paste when working on CF because our customers don't appreciate having their expensive CF parts broken, and neither do our employers?

if its your own bike or parts, then obviously do whatever you feel comfortable with. But personally I have torque wrenches at home because even when working on both my carbon bikes I don't want to be fixing them with improper torque
  • + 2
 Point taken .thanks
  • + 1
 @superbikes

no problem!

I have too many first hand experiences of customers buying expensive CF finishing kit (bars, seatpost, etc.) proclaiming they don't need / want a torque wrench and then coming back the next week with the seatpost or bars cracked, and sheepishly admitting they used a multi-tool or p-handle to tighten the seat clamp or stem fitmentsFrown


in those instances, we would usually sell them another seatpost or bars at our cost (out of goodwill) and also an affordable torque wrench, and give them some basic instruction in its usage Wink
  • + 2
 I've always sworn by the good ole guttentite method.
  • + 6
 So many people here are never working on my bike!! EVER
  • + 0
 this torque wrench is a must have to any mechanic! But make sure you get the one with all the socket and cap fittings with it!
  • + 1
 Torquewrenching things like bolts is fine, but how are you supposed to torque something like a bottom bracket?
  • + 1
 Huge friggin' torque wrenches.
  • + 1
 @dirtydroog

with the correct fitment (HT2 or Shimano / ISIS pattern adapters for BB units) plus suitable torque wrench (typically automotive with 10-70nm range)

like this: www.motorcyclenews.com/upload/262880/images/Halfords-torque-wrench.jpg

we also use this tool and suitable adapters for cassette lockrings which use 40nm
  • + 1
 i've had a totque wrench for years and never felt the need to use it,tightening by hand as never let me down.
  • + 1
 My trusty clicking wrist has to do the job until I'm stinking rich.
  • + 1
 but my bike just a city bike -, -
  • + 1
 I hate significant injury (to me or my bike).
  • + 1
 I love my torque wrenches!
  • + 1
 Is there any list of torque settings for the major of bolts/parts?
  • + 2
 You will most likely have to go to the manufacturer for that information.
  • + 2
 Park Tool's Big Blue Book of Bicycle repair has general guidelines for most major components and brands. Definitely a worthwhile purchase (the book and a torque wrench).
  • + 2
 See wirkus24's comment above for parktools link.
  • + 1
 what happened to the german torque specs? good n tight
  • + 1
 As a mechanic I use a torque wrench mostly for liability reasons. If I use proper torque on every bolt and something fails down the line, none of it can blow back on me or the store.
  • + 1
 never lost any part of my bikes... ever,,,
  • + 1
 My canfield frame had a bolt over tightened by a previous owner. This caused the frame to break in a place that can't be repaired, so Yeah, torque figures really do matter in some cases.
  • + 1
 I call BS on this. Your frame broke due to 1 over-tightened bolt? That just shouldn't be possible, and if it did happen, it smacks of (very) poor design. Not something I'd normally associate with Canfield.
  • + 2
 @foghorn1 good thing you said that because i was thinking about buying your canfield. probably should mention broken frame in your add
  • + 1
 Uh my broken canfield is a Balance. THe F1 is just fine.
  • + 1
 Brit-100 I'll post a pic in my album parts etc.
  • + 1
 people in Louisiana dont even have mountains Smile ))))))
  • + 1
 After tight comes loose.
  • + 1
 Brilliant.

Even better: righty tighty, lefty loosey.... when in doubt, use your teeth to torque fasteners.
  • - 2
 what happened to hand-tools?
  • + 4
 Carbon fiber.
  • + 9
 They started making them with capabilities of measuring applied torque..

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