The overuse of Torque settings for fixings ?

Waterworks · Apr 28, 2021

An argument I'm having with a high end bicycle owner that the torque specs the bike manufacturer is giving out for non critical components on bicycles are just superfluous and only exist so customers can feel more " high techy". Naturally he is now furious and waving his 1/8 " torque wrench at me.

Things like seat post clamps, brake levers and just basic bolted on parts which are usually stainless bolts into aluminium fittings. I was taught that torque specs on the Diesel engines I worked on were only for the first set down, after that the metal had moved or the bolt stretched and the initial spec was then redundant?

What do you think ?

Richard King · Apr 28, 2021

Email or call these guys. I used to rebuild their machine tools. I am sure they can help you.

About - Bike Thomson

Orbital77 · Apr 28, 2021

Waterworks said:
An argument I'm having with a high end bicycle owner that the torque specs the bike manufacturer is giving out for non critical components on bicycles are just superfluous and only exist so customers can feel more " high techy". Naturally he is now furious and waving his 1/8 " torque wrench at me.

Things like seat post clamps, brake levers and just basic bolted on parts which are usually stainless bolts into aluminium fittings. I was taught that torque specs on the Diesel engines I worked on were only for the first set down, after that the metal had moved or the bolt stretched and the initial spec was then redundant?

What do you think ?

I think you should follow torque setting where it matters. Cars, trucks , a/planes etc. Bikes, I don't know. The torque is intended to bring the screw to a certain tension.

TGTool · Apr 28, 2021

I would wonder if the torque specs were a CYA for bike manufacturers with threads in aluminum. There should be a tightness value that holds the components without damaging the aluminum threads. If owners or others don't use a torque wrench and the threads pull out, the mfg can just shrug and say "I told you."

Mark Rand · Apr 28, 2021

Many fastenings on pushbikes are small diameter. Posh bikes also go in for aluminium parts and stainless or titanoim fasteners. The torque specifications are to prevent the owner/mechanic from buggering up the parts*.

*When a work colleague brought me an aluminium bike bracket with a sheared off titanium bolt in it, I wasn't impressed...

DDoug · Apr 28, 2021

Waterworks said:
An argument I'm having with a high end bicycle owner that the torque specs the bike manufacturer is giving out for non critical components on bicycles are just superfluous and only exist so customers can feel more " high techy". Naturally he is now furious and waving his 1/8 " torque wrench at me.

Things like seat post clamps, brake levers and just basic bolted on parts which are usually stainless bolts into aluminium fittings. I was taught that torque specs on the Diesel engines I worked on were only for the first set down, after that the metal had moved or the bolt stretched and the initial spec was then redundant?

What do you think ?

It's for in-experienced people, that have no feel to what is needed.

However, I'll bet on a Toyota/Honda engine assembly line, a torque wrench is used on the oil drain plug. It's to eliminate problems.

Boat Brat · Apr 28, 2021

Waterworks said:
An argument I'm having with a high end bicycle owner that the torque specs the bike manufacturer is giving out for non critical components on bicycles are just superfluous and only exist so customers can feel more " high techy". Naturally he is now furious and waving his 1/8 " torque wrench at me.

Things like seat post clamps, brake levers and just basic bolted on parts which are usually stainless bolts into aluminium fittings. I was taught that torque specs on the Diesel engines I worked on were only for the first set down, after that the metal had moved or the bolt stretched and the initial spec was then redundant?

What do you think ?

Torque on bike fittings usually has little to do with the SS/Ti screws and alloy fittings that they go in to. But everything to do with the super thin carbon components they are mounted on. Plenty of people have crushed carbon steerer tubes, seat posts and handlebars. None of the above have a happy ending when they give way while at speed!
I would follow the recommended torque settings unless you have good reason not to. If something is still slipping they sell grip paste to go between the components.

Would be interested to know what components have a torque stated but are not critical on a high end bike?
I’m struggling to think of anything on my bike...

Edit, maybe the pedals on to the crank is not needed, just bloody tight. But that is a bigger thread. Everything else is small and in close proximity to thin carbon.

Demon69 · Apr 28, 2021

Waterworks said:
What do you think ?

If the guy is devoid of experience and basic mechanical common sense. Tell him to use a torque wrench on everything, inc his helmet strap.

Conrad Hoffman · Apr 28, 2021

I have this problem/argument at work quite often. I think it comes down to how much experience somebody has and also if they have the mechanical "knack". See Dilbert on the knack. With experience you can feel things start to yield and develop a feel for when to stop and for what's reasonable for the situation. OTOH, fewer and fewer people grew up working with mechanical things and just don't have a clue about how things should feel. Others have the experience but are so paranoid about things falling apart that they horse down too hard on everything anyway. Torque specs provide CYA for the manufacturer and are actually useful for the inexperienced. Of course then you need to talk about fastener age, history, cleanliness and lubrication.

DanP_85 · Apr 28, 2021

For seat post clamps on carbon bikes it's critical, too tight causes damage to the frame and too loose is a problem... Similar for carbon bars and brake levers, there have been several high profile crashes in professional racing from snapped bars at the edge of the clamp due to too much clapping pressure (this was early on carbon was new and the industry hadn't learned). It's less torque for these two applications then you would think.

I guess it depends, some of it is wank but it takes a reasonable bit of experience to know what is important. I've got a nice low measuring range 1/4" torque wrench and two mountain bikes that are carbon, I use it for a few things on those bikes on those two fittings but others parts not. Never used it on my steel hard tail.

With an Allen key you can develop enough force to pull the threads out of a taped aluminium or plastic inserted hole, most machinists know this by feel, as do most bike mechanics, the general public on the other hand.....

GregSY · Apr 28, 2021

I think most replies are on the mark. The torque spec reduces the chance of someone who is a dummy doing it wrong. And while soybean and barley crops have suffered, the world is producing idiots at an abundant rate.

That said.....even torque specs are a lot more of a suggestion than an exact science. When Lexus uses a $250K machine in a clean room to tighten your main bearing caps, that's science. When Juan Hernandez does it using a no-name Chinese torque wrench in a shed, that's a suggested serving.

And we all know the type of lubricant you use, and where you use it, will have a huge effect on actual bolt stretch.

johnoder · Apr 28, 2021

Here is Harry A. Miller - 1920s maker of racing cars - like Indy domination

Notice tools on display - and the absence of any sort of "torque wrench"

Even an absence of any sort of modern socket set - to use on your invisible torque wrench

I would imagine the little straight eight is the 91 cubic inch job.

Maybe there was more to his assembly tools than his display board?

boslab · Apr 28, 2021

These days even electrical panels have torque settings on grub screws, you need a torque limiting screwdriver to stick a wire in a panel.
I suppose it’s easier than trying to retrieve stripped threads, I had to change a panel because a Sasquatch had tightened the cables, threads sheared and glowing on IR.
Mark

4GSR · Apr 28, 2021

Conrad Hoffman said:
I have this problem/argument at work quite often. I think it comes down to how much experience somebody has and also if they have the mechanical "knack". See Dilbert on the knack. ...................................

Somebody recently told me I had the "Knack".

My son jumped my case about not using a torque wrench on tightening up some bolts a while back. Told him if he didn't trust my tightening arm to go behind me and use your Asian torque wrench. He did and didn't say a word. They were torqued up pretty darn close to what the book said. We never did have a torque wrench growing up, we learned by feel and experience, especially when a fastener failed.

DDoug · Apr 28, 2021

4GSR said:
Somebody recently told me I had the "Knack".

My son jumped my case about not using a torque wrench on tightening up some bolts a while back. Told him if he didn't trust my tightening arm to go behind me and use your Asian torque wrench. He did and didn't say a word. They were torqued up pretty darn close to what the book said. We never did have a torque wrench growing up, we learned by feel and experience, especially when a fastener failed.

...And now, when torquing a fastener, say "Click" when you are done....

MCritchley · Apr 28, 2021

johnoder said:
Here is Harry A. Miller - 1920s maker of racing cars - like Indy domination

Notice tools on display - and the absence of any sort of "torque wrench"

Even an absence of any sort of modern socket set - to use on your invisible torque wrench

I would imagine the little straight eight is the 91 cubic inch job.

View attachment 320078

John that was 100 years ago, bike components have changed as have gasoline engines. My auto mechanic torque's each lug nut to the manufactures specifications, mostly knowing a lug will not come off when a car is doing 80 mph in traffic. Same thing with exotic bike component's, the manufacture most likely did some some research and was nice enough to publish these torque values so as the rider will not have an issue. Old Harry miller lived in a different time.

M.B. Naegle · Apr 28, 2021

I'm in the "pro: torque settings" crowd. Yes people should know how tight tight is... but they don't.

The other side of this is that ESPECIALLY in things like high end bikes, every nut, bolt, and washer has been engineered to a super fine line with no waste, just the bare minimum to get the job done so they can keep weight and cost down, so the line between loose and stripped is almost impossible to "feel." This way of engineering/building things has permeated manufacturing these days. It's not uncommon to strip a thread out of a kitchen-aid mixer or break the head off of a screw in the back of your PC and people rant about "that's China's fault!" but in reality, it's the engineers who designed bare minimum material and fastener specs, who are often sitting in a high-rise in an American city, not overseas. In cases like the OP's bike, those manufacturing specs are needed to keep people from killing themselves, in many other cases it's just poor manufacturing practices, but in both cases, doing the job how the OEM says often leads to the best results. If it's an old machine with no torq specs, do it by feel and feel good about it, if it's a BMW bumper with 200 pages of torque specs, do it with the right wrench and sleep better at night.

jim rozen · Apr 28, 2021

Harry Miller would *never* leave a precision instrument like a torque wrench out on a tool board. He kept it safe in a case, in his precision tools box.

Natch.

Bet a box of donuts he had more than one torque wrench, and used them for more than just impressing customers.

GregSY · Apr 28, 2021

Harry Miller was a great guy, and I love reading his books about the filthy things he did to Ms. Nin, but a 1920's engine? It hardly mattered how the fasteners were torqued. It was a different world. By modern standards, the engine was probably also grossly out of balance and working at 20% of its material strengths.

Orbital77 · Apr 28, 2021

GregSY said:
Harry Miller was a great guy, and I love reading his books about the filthy things he did to Ms. Nin, but a 1920's engine? It hardly mattered how the fasteners were torqued. It was a different world. By modern standards, the engine was probably also grossly out of balance and working at 20% of its material strengths.

You are (horribly) kidding yourself.

The overuse of Torque settings for fixings ?

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