Fritzenheimer

Should I be concerned? I'm a Noob.
Bought a new carbon bike there a few weeks ago and when they were making seat height adjustments and tightening up some other things I asked why they weren't using one.

The response was basically we've done this so much we know by feel not to over tighten. Not feeling good about that. Am I worrying too much?

hockeyteeth

I wouldn't worry about it too much. Get one of these and you'll eventually develop an idea of what 5nm feel like:

https://www.amazon.com/Ritchey-M4-Bic.../dp/B005U7E2E8

Airburst

I wouldn't be concerned, my grandfather knew a guy who could tighten down the cylinder head bolts on an engine without a torque wrench (apparently you do each one up to a small torque value, then tighten them each slightly in turn, keeping them all very close to equal torque to avoid warping the cylinder head). If he could do that, I'm sure your LBS mechanics can work on any bike, carbon or otherwise, without a torque wrench if they've been doing it for a few years.

robo

Depends entirely on how much you trust the mechanic. If they're truly experienced and careful, it's probably fine. If the mechanic is a gorilla, then you might have a problem.
In my entirely subjective experience, about 2 out of 5 bike mechanics are not gorillas, so there's a nonzero chance that you'll be just fine...

(Although honestly for a seat height adjustment, it's so routine that it's probably fine.)

FBinNY 

You're probably better off with a mechanic with the skill to tighten by feel, than one who blindly relies on a torque wrench. The issue isn't the torque wrench, but the blink faith in it.

Torque specs and torque wrenches are fine, and valuable in making sure that all is right, but there are variables, and most skilled mechanics who use torque wrenches, make adjustments anyway based on feel and judgement.

Ira B

A truly experienced wrench turner is probably no more likely to damage something without using a torque wrench that using one and will know when doing or not doing so really matters.
Final re-torquing of cylinder head bolts on a VW diesel engine, it matters.
Careful tightening of a seat post clamp bolt, not so much.

rydabent

If I owned a high end bike, I would be highly concerned!!!! I worked with a large number of technicians that thot they could do adjustments by feel. I cant tell you how many time I had to bail them out because they adjusted things wrong. Mechanics that do things by "feel" are a dime a dozen!! Real mechanics use the proper tools!!!!!

ultraman6970

I would not care that much, for the record like 8 or 7 Newtons that is what a stem clamp needs is a lot of torque, a lot more than somebody could imagine, the issue is that you have warranty and people is pretty anal sometimes with torque tolerances. I believe them when they say that they know when something is tight or not. The other issue is that the op clearly doesnt do his mechanic or the bike wouldnt be in a store to start with. So pretty much if he tight a bolt with no torque wrench probably he will leave the bolts lose or too tight, probably he has no idea how it feels to over tight something or how it feels that is not tight enough until the parts slide up or down.

If you dont want to worry about who is fixing your bike, and this is a msg to all the guys that worry about torque and are anal about tolerances and have no idea even how a torque wrench works, then do the stuff youself. Is the only way to ensure if something is done right or not.

The issue is that people just blame the store because they did something wrong, well fix a bike is not rocket science, is not even that complicated like learning diesel engines or even an advances math class. This is a subject that has come several times in the forums and is always the same thing. A poster complains about the store, well you have good and bad shop mechanics but the solution to the problems and worries is always the same, do the stuff yourself. You screw up, you'r bike wont work. They screw up you come to the forums ranting and blah blah blah... Do the stuff yourself,is the only way to get the stuff done right how you like it. The other thing, stores dont like PITA clients, and some clients are a real PITA specially the anal and ones with problems in the head like the ones with traces of paranoia.

Good luck man

mechBgon

Real mechanics also use common sense and experience. I was recently showing an owner of a VERY high-end bike how to pack his bike in his new bike case to travel to IronMan. When we were putting the bike back together, I inserted his carbon seatpost and began fastening the clamp. Well we don't want to scandalize this guy by doing this by hand... I'd better use my Precision Instruments torque wrench, right? And I did. And the seatpost broke, at about 60% of the target torque spec. It's a dial-readout torque wrench, so I can continuously see how much torque is being applied.

In this case, all the parts are from the same company, they developed the torque specs, and it's dangerous to blindly trust them as a substitute for experience and common sense. On the flip side, when we filed a warranty claim with Large Bicycle Company "T" for a replacement seatpost, they were initially going to refuse it, but when we pointed out that a torque wrench was being used and we were well below the spec, they had no grounds left for refusal.

davidad

Go beyond the superstition and use a torque wrench to check their work. A beam type is not expensive and very accurate.

skoda2

I often assemble and adjust new bikes out of the boxes from a Large Asian Country beginning with C and MANY of the components already attached to the frame,were I suspect tightened by the above named gorillas or an air wrench set too high. Sometimes I have difficulty loosening them to properly adjust the components. I've been wrenching bikes since the early 70's bike boom and the only times I've stripped threads was when they were cross threaded to begin with.

FBinNY 

You cannot use a torque wrench to check a fastener that is at, near, or above torque spec. the stationary friction (sometimes called stiction) is higher than the moving friction. As you smoothly bring a bolt to torque spec, you're dealing with moving friction which is what torque specs are calculated on. Once you stop, you'll need significantly more torque to break the bolt loose in either direction, causing you to assume that the fastener was originally overtightened.

If you want to "check" work with a torque, you have to back off the fastener, and retighten with the final movement smooth and steady to get a correct reading. So you're not as much checking the work as redoing it.

Don't take my work for this. If you have a torque wrench, tighten a bolt to a value-- any value within the range usually considered tight. Stop, then try to tighten it farther while watching the values on the torque wrench. repeat the experiment, but loosening a bolt while watching the wrench scale.

Torque wrenches are fine tools, and very good for certain applications. But if you don't understand the principle, and know when and how to use them, they're just expensive, complicated socket handles.

BTW- over 45 years in the industry, making and selling tools, and teaching mechanics, I've come to the conclusions that the skill of mechanics and the number of tools they own are often inversely proportional. Yes, good mechanics have and use good tools, but they were good mechanics before they bought the good tools, not the other way around.

gforeman 

I have a few torque wrenches. I do my own mechanics on motorcycles, bikes, and cars. 90% of the time, I just use my hands and common sense. I do use it when tightening the lugs on my vehicles. Not so much to get a specific torque, but to ensure all are torqued the same. If not I have seen the rotors warp. I have been using it on a few things on my bicycle, because I need to make sure it's cranked down because of issues, and not wanting to strip it off. My seat post for one, a lot of creaking going on. Specialized gave me a setting of 55 in lbs. That is slightly more than I was doing by feel, and it resolved the creaking.

I can't remember the last time I stripp...Okay, going to shut up and knock on wood right now

If they are good/experienced, I would trust them.

Ira B

I own a dozen torque wrenches that range very small precision ones to a monster designed to properly torque prop nuts on DC-3's.
When I need them I use them, when I don't I don't and I rarely use one bicycles. It has been so many years since I experienced a negative torque related issue on anything that I honestly don't remember it.
On smaller nuts and bolts as are found on bicycles I have a pretty well developed feel for "just right" and would prefer that over just blindly torquing something to a spec that does not reflect real world factors like are the threads lubed? Clean? In good shape? Temperature? Unusual application?
That said, If you are not a long time wrencher you may want to use a torque wrench. If nothing else it will help you develop your "feel" for torque.

Al1943

Not so!
My stem shows a recommended torque of 8 nm. My $850 Colnago Star fork steer tube broke at 8 nm. This was using a 1/4 drive TW 2 Park torque wrench. 5 nm is plenty for any stem.

zaqwert6

Depends on everything that's been stated already however, I would be concerned about a shop that doesn't have one at all versus someone that's capable without one . If that makes sense. Torque is such a concern in this industry today, any medeocre shop at least should at least have one available IMO.

gmt13

Just because a mechanic has a torque wrench, and said mechanic knows how to use it, does not mean that the bolt, etc. will be tightened to the right torque. Why? Well it so happens that all torque wrenches need to be calibrated. If the wrench is not calibrated, you have no idea what torque you are applying. A mechanic working by feel, learned through much experience is much better than an inexperienced mechanic trusting a torque wrench out of calibration.

-G

mechBgon

That's overly generalized. There are stems where 5 N.m is far from sufficient. Maybe you meant lightweight road-bike stems specifically?

Actually, there are torque wrenches that cannot be calibrated, and won't need to be. Specifically, beam wrenches, where the spring rate is the inherent bending properties of the beam itself. You can't change it... not in any controlled fashion, anyway. You could reduce it by shaving metal off the beam, I suppose You can also change the zero point by bending the pointer... but that's not calibration, that's zero point. Also, the amount of actual clamping force generated by a fastener can vary a great deal just on the basis of whether the fastener's head and threading are lubricated or not.

Ultimately, bikes are not uber-precision, fully-engineered products where minor calibration drift on a torque wrench will result in a blown fuel line at 30,000 feet. Don't overthink stuff

Retro Grouch 

You can't work on my bicycle.

7 or 8 Newtons is about 65 in/lbs or roughly 5 ft/lbs. Imagine a 5 lb. weight hanging off of the end of a foot long wrench. That's not very much torque. It's barely anything.

One measurement is worth 1,000 assumptions. I use torque wrenches because, if left to my own assumptions, I would consistantly under torque cranks and bottom brackets and over torque stem clamps.

gmt13

Yep, you are right about beam type wrenches; however their accuracy is a function of the scale provided (has it been calibrated?) and reading error due to parallax or lack of competence. Torque wrenches attempt to measure bolt tension which, as you said, is highly variable because of thread friction.

It seems to me that the worry about torque these days is related to the fragility of modern materials.

-G

Burton

Torque seems to be a lot like tire pressue - lots of people - professional snd otherwise - seem to think they can guage things by feel. And double checking things with a tire pressure guage or torque wrench almost always confirms they weren't close enough to target.

For anything that calls for a specific torque range - every mechanic in the shop I work in is expected to use a torque wrench, and every tire is checked with a pressure guage.

ultraman6970

I wouldnt either, you look like a pretty anal person with specs dont take it bad, just saying no bad intentions

Thats why i work only in mines since maybe 30 years never have problems, and the tiny problems i remember had been just my negligence Not even have a torque wrench (lie, i do have one, still in the bag), we did not have that back in the day and with carbon never had a problem because I use carbon paste, with that the torque needed is reduced a lot, excellent invention. Moved off aluminum stems maybe like 6 years ago? never a problem Dunno man, all the horror stories and rants that happen to people never happen to me Good luck with bikes mechanics, bad luck with money and work The other thing is that I'm not a freaking monkey with orangutan force too... laaaadies man...

[QUOTE=Retro Grouch;14511173]You can't work on my bicycle.

Ira B

Totally agree about tire gauges.
I've tried many times to guess, double checked with a gauge and have rarely been close enough for my liking.

mechBgon

Then I have some advice for you: if you get a Trek Speed Concept in for repair, think carefully before you try for anywhere near the torque spec engraved on the seatpost clamp. I'd treat it with carbon grit compound and go with about half of the marked torque, followed by a Reality Check to see if it's sufficient to keep the post from slipping. Breaking one by using the "correct" torque will be an expensive mistake: https://bontrager.com/model/08926

Burton

Or maybe not ....... if you follow instructions you're covered by warranty. And might help the company turn up QC issues: " The seatpost kept slippping, even with the hidden clamp tightened to specified torque. Trek attributes this to a slightly undersize seatpost. New bikes ship with a revised post and early purchasers can get a free clamp assembly from Trek to eliminate the problem."

When Ergon grips are returned under warranty the first question the company asks is: "What brand and model of torque wrench was used for the installation." No torque wrench - no warranty.