From what I have read elsewhere the importance of the correct torque setting has come from the use of carbon parts. Whilst over-tightening of anything has its own problems, I have seen some crushing of very expensive parts, especially handlebars, due to over-tightening.

We take into account the material of the parts being fixed together (Yield strength etc…), the bolt material, the head size and the likely compression of the parts in the joint.

We calculate the bolt torque to give sufficient clamp load to hold the joint together. We consider the head diameter of the bolts – to check that the head won’t compress the parts being fixed and thus lose tension from the joint. We consider the vibration and all external loading on every fastener and joint and all this to ensure that once tightened it won’t come loose.

Uhuh.
This is what happens on bikes.
The Guy who has to write the guff on how to use the component asks the guy who designed the component what torque a bolt needs to be done to. He asks this question because he’s noticed all the other companies have these numbers so feels he should add them too.
The guy who designed it then responds in one of two ways, he either makes up a number that sounds about right, or he gets a torque wrench and does the bolt up to what feels right and notes the reading.

Fresh, clean threads, clean surfaces, correct preperation , yes, torque values are very relevant.

Take bike parts which are dirty, corroded, I’ll prepped, distorted, out of tolerance, torques are certainly no longer representative of applied loads.

Torque values certainly have their place on manufacturing lines and in industry, I just don’t feel they’re anywhere near as relevant on a bike.

Ianmunro sounds to have it spot on though.

So how often do these torque wrench users get their wrenches calibrated?

ti_pin_man

Every mechanic is taught that torque is important

Every engineer is taught that fastener/joint strain is important

EFA^^^ 😉

But no, you don’t need a torque wrench for a bike generally speaking. Very few fasteners will be absolutely “torque critical” and none will be torqued to yield. Yes, you need some measure of ‘feel’ while you tighten any given fastener, and a general appreciation that an M4 SCH should not be tightened as much as an M8 SCH etc!

My experience of low cost torque wrenches, especially ones used to tighten bolts to low absolute torque values (<20nm) is that they are generally highly inaccurate, and how the operator holds and uses them can be critical too (especially for the “clicky” type)

Tough one, I think few in the bike trade used a torque wrench for decades.

I can see some potential merit for light/fragile/critical parts like carbon stem face plates or similar, but as said above, most of us can tighten a bolt to hold something on without damaging it with experience.

My suspicion is it’s something that’s been imported into the bike world to sell us more tools and make stuff sound more technical.

I thought the “torque settings” on MTB components are there so that manufacturers have a get out of jail free on warranty claims.

ChunkyMTB – Member
So how often do these torque wrench users get their wrenches calibrated?

Standard torque wrenches/drivers are a 12 month calibration in my line of work.

http://www.ciclipinarello.com/else/garanzie/PinarelloENGLISHweb.pdf

Pages 10 and 14

nickc – Member

I thought the “torque settings” on MTB components are there so that manufacturers have a get out of jail free on warranty claims.

…and sadly that’s all too necessary if you’d seen the number of trashed components they get back because some people aren’t capable of tightening anything up without using a 3 foot-long extension bar.

I worked alongside a major U.K. warranty department for 3 years and the vast majority of snapped bars, seatposts, brake or shifter lever clamps, steerers and saddle rails were clear cases of people massively over tightening the respective clamps.

A component manufacturer has two options if they want to avoid being sued:

A: Make their components largely immune to cack-handed assembly by hugely over-building them and making a loose bolt or two less important (6-bolt handlebar clamps etc). And then watch their sales plummet.

B: Stipulate torque settings, those with a bit of common sense won’t need them but it prevents the manufacturer being liable for idiots who should never be allowed near a tool kit.

It’s no coincidence that recommended torque settings have emerged in line with the trend for people buying high-end components mailorder and fitting them at home.

Oh, and regarding recalibrating torque wrenches, if you have a decent one, store it carefully, reset it to zero before you put it away and don’t drop it then it’ll go for years without needing calibrating.

If you have a cheap one, use it frequently and treat it rough then it’s going to need much more TLC.

Torque wrenches are very relevant, especially if your boss used to work on harriers. He is banned from screwing anything up! In honor of him we have a unit of Torque named after him called a “Spellman” (c). It is precisely defined as the point you feel the threads fail be it M3 or M20! 🙁 😀

Well, thats a somewhat bigger response than I was expecting!

It’s quite interesting reading everyones replies. I’m not an engineer, so did’t realise a torque-wrench would need calibrating, and to be honest didn’t think it all through enough to consider thing like the temperature of grease used would effect the readings. These variations lead me to believe that there isn’t a huge amount of point in getting one.

I tend to think I’m reasonably sensible with the ‘feel’ of bolt torque. I’ve never had anything come undone on the trail. I’ve never sheered a bolt head or broken a part. The only time I’ve had something move on the trail was when I rode into a tree 😳 at which point the stem move on the steerer as you’d expect.

Disassemble and clean, grease, reassemble.

Done this several times, no luck. I’ve had the headset from new too, so I’d doubt it’s the bearings.

I had a similar problem and eventually traced it back to the brake cable outer going into the housing on the top tube. Some light grease every so often stoped the noise

I’ll give this a go, never even though to check if it was cables. Pretty sure it’s coming from lower headset cup area though.

OP, if your fork has QR dropouts, check that the skewer is tight.

15mm axle here, but I did check it wasn’t loose.

These are pretty good for bars and stems, I’ve taken to using one every time now. It’s a neat handy tool and you know your 4-bolt faceplate or 2 bolt stem is perfectly evenly tightened. Other than that the only time I get a torque wrench out is for cassettes with ally spiders

Should probably recognise the logo, but who makes that one?

Not strictly, and yep: calibration is a consideration especially if you drop it, lewt others use it, keep it in the shed or forget to zero it after use.

My twopennorth’: I’ve seen too many mates end up with wrecked things because it turned out that ‘yorkshire tight’ was too much.

Unless you go crazy and buy a super expensive one (£20 gives you a choice), the first time something snaps and you have a major job of cutting slots and stuff as a result may be the time you see the benefits. Sure the £20 option is unlikely to be cock on but it may be a better guessing stick than your tendons.

I personally bought a small bike size one after accidentally pinging a steerer cap bolt and not having a spare (although the unsupported forks were probably the real cause) which trashed a couple of rides.

I’d agree that most people tend toward ‘way too tight’ but I’ve also been guilty of undertightening. For things like stem faceplates (comments about bar fails above) it’s important to tighten crosswise and progressively rather than doing the first one up as tight as you can then starting on the second …

Overall, I think torque wrenches basically buy peace of mind that things are less likely to fall apart on you, which is nice.

Oh, and unless the instructions SPECIFICALLY say to grease the bolt you’re about to torque, don’t. You’ll end up way tighter than planned as the grease makes the torque wrench into a liar…

oh, and +1 that the FSA head doctor-alike is your likely creaking problem here unless your faceplate bolts are way too tight/uneven.

Oh, and unless the instructions SPECIFICALLY say to grease the bolt you’re about to torque, don’t.

I grease everything – well, everything apart from the things that get threadlock. If you don’t grease then (apart from corrosion, galling etc) you’ve got no standard of stiction, you don’t know if the bolt is right because it’s tight or because it’s stuck.

When I’m tightening up something I don’t want to break I use a torque wrench. It’s calibrated (I manage a UKAS stds laboratory) and I know when I’m using it nothing ‘should’ be over or under tightened.

I don’t want to break my expensive bike components so I use my torque wrench/driver. If I was constantly building bikes for a living, I’d probably use it less as I’d get more of a ‘feel’ for what I was doing.

That’s the thing – I don’t use a torque wrench for the same reason I don’t use an infrared thermometer when brazing – practice means I’ve got the feel of it.

If you don’t do enough bike spannering to get that feel, then a (decent, well-calibrated) torque wrench is a good idea for piece of mind.

legend – Member

ChunkyMTB – Member
So how often do these torque wrench users get their wrenches calibrated?

Standard torque wrenches/drivers are a 12 month calibration in my line of work.

Depends on how much you use them, in the Aerospace industry where torque settings are critical, some people have stipulated frequencies of anything down to monthly, My main client has a ‘Standardised before use’ policy, i.e. calibrated against a master.

Though, it does depend on how many you have or how much it costs to calibrate them. (Generally) the more you have, the longer the frequency. *geek* I’m not sure if BS26798 has a recommended frequency and I cba to look *geek*

It’s a bit not simple really. I use a torque wrench very occasionally on the pushbikes, on silly torque-sensitive cranks as I can’t accurately judge 50nm. But for everything else I use my torquefingers, which are pretty accurate.

Course, you aquire accurate torquefingers over a lifetime of breaking bolts, stripping threads, and having bits fall off. Getting a torque wrench (or 2) is probably easier.

But then, if you never aquire any sort of torque-sense, it becomes fairly likely that sooner or later something is wrong- a crossthreaded bolt, or a blocked thread, or a too-long bolt, or you just set the wrench wrong or read the torque wrong (or you’re reading a Suzuki service manual and a bunch of the settings are mistyped)… and you trust the wrench and then, bad things occur.

What make is the red wrench up there ^

Bontrager – Preset Torque Wrench

http://trekbicyclestores.com/product/bontrager-preset-torque-wrench-76318-1.htm

Torque wrench when dealing with carbon parts.

I grease everything – well, everything apart from the things that get threadlock. If you don’t grease then (apart from corrosion, galling etc) you’ve got no standard of stiction, you don’t know if the bolt is right because it’s tight or because it’s stuck.

Screws / bolts work due to the balance between friction in the thread and tension between the shank and the head. If you lubricate them, then the friction goes down so the tension must go up. It increases the risk of bolt heads shearing which is potentially more disastrous than if they slip. So, I never grease bolts that shouldn’t be greased.

Bolts should have either antisieze or loctite on…. Pending use, but grease not unless i had absolutely nothing else.

I did a mini service of my own Fox’s.

Everything back together, and as I “zipped up” the last nut on the bottom of the fork using my small palm sized ratchet (much quicker), torque wrench on the side ready for the final click…..

… “ping” snapped aluminium thread rod, and a large bill next time I want them serviced.

In my defense they are 7 year old forks, so who knows how many times that part has been work hardened by flying rocks, but now I’m just justifying my laziness 🙂

I know I gave a very polarised opinion earlier in this thread – it was intentional.

I believe that torque values are very important in my business (car design) and that they save countless problems.

On a bike… it’s not so clear cut. I don’t use a torque wrench on the smaller stuff. And I don’t use one at all unless I feel it’s absolutely critical or it coming undone would be a disaster/safety problem. I believe I have some ‘feel’ for this stuff after spending my whole life fixing cars and building bikes and repairing stuff.

BUT I do know how hard we work to specify the right value – so I’m also conflicted 😯

Which is quite funny when the only places ive seen a torque wrench being used on a car are fitting the head and nipping wheel bearings.

Different for designing em though.

I rather enjoy reading the monthly “torque wrench” threads on stw, so many home fettlers and “engineers” with magic fingers in one thread makes for an amusing 5 mins of reading.

For what it’s worth (as this is stw – very little indeed) i use a Norbar SLO 1/4″ drive at work on customers bikes along with 4nm/5nm/6nm 1/4″ bit driver finger torque wrenches by Snap On, i use them every day and if i entrusted my £5k carbon wunda bike to a shop i’d expect them to use one as well, although i personally would never choose to own a plastic bike so i guess that’s another discussion/thread entirely, and my torque wrenches do get calibrated at least once a year, i also do a fair bit of vehicle mechanical work as well so i like my tools to do what i expect of them.

Not a week goes by in the shop that i don’t get the job of either removing sheared bolts or rounded out Hex heads or re-tapping threads due to customers who are so ham-fisted that i’m surprised they manage to feed themselves without piercing their jugular with a fork at every meal time/opportune moment, some folk may mean well when they attempt a quick tweak or repair but i’d rather they just got on with the business of riding their bike(s). Centering a £200+ stem in a chuck as you attempt to drill out a 6al/4v Ti 4mm bolt that they have managed to cross thread and shear is not a productive use of my time, although i do apply the “stupid tax” on the bill afterwards they’re is always the chance that i will not be able to rescue the item and thus feel inadequate and spend the rest of my day in a sulk.

Which is quite funny when the only places ive seen a torque wrench being used on a car are fitting the head and nipping wheel bearings.

Hmm…….depends on whom or what garage does the work, although i tend to agree wi you, when i was in the trade i came across some absolutely shocking mechanical ineptitude and ham-fisted use of breaker bar use for everything, which on critical items like suspension/steering bolts or calliper bolts etc was quite frightening sometimes.

Personally i use one on my car, (fully rebuilt mk2 abt golf) and every suspension/steering/drivetrain item nut/bolt/washer etc was replaced for OE or better quality and torqued then a good majority of them have been lockwired for security, i followed the specs coz i’m kinda anal like that but more so that i could have absolute faith in the car when i’m at 10/10ths so to speak, I want to know i can place 100% trust in what i expect of the car……..the car is a hoot to drive, however the driver is very fallible and needs constant attention 😉