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View Full Version : Bullshit Torques, Math Walks (or something, I worked on the title too long).



F5 Dave
3rd July 2025, 16:19
I’ve had my Torque wrench 30 years. I’ve never abused it, always wound the tension off after use. It is the Holy Teller Of Truth when it comes to tightness.

And to be honest I don’t use it on everything, I’ve ‘decided’ that I have a pretty good feel for how tight and dangerously excessive. Mechanics will laugh or agree in secret of their own amazing ability, unlike those other losers who strip every third bolt.
My elbow clicks at the right Torque :)

Always used it on cranks and head-nuts though.

Triple clamps are a good area for caution. Too many torques can squeeze ally uppers affecting action, apparently. The lower clamps are set not that tight really.
In fact, it was this area that I hand tightened and then reached for the Torque wrench. I didn’t have my manual or phone on me, so I wrote a piece of tape on the Tank to recheck everything attached to the forks. I then read the suggested settings off the Beta which are actually screen printed on the triple clamps (cool huh?). I figured then would be in the low side of things being a very light bike. It would be more for the Adventure bike so it was a safe setting for now.
The Torque wrench clicked straight away meaning that my hand guess was either bang on, or too tight. Hmm.

So I found a dumbbell and a coat hanger, put a sacrificial bolt in the vice and adjusted the wrench to an arbitrary setting, fairly low. The weight was too heavy and set it off even when adjusting it down to lowest 10Nm. So I adjusted it to 15 and moved the coat hanger up the handle so it just clicked, and 2mm up it wouldn’t. So I marked where it would. I measured to the centre of the square drive.
Working in foot pounds and inches it was Length in Inches and weight of dumbbell divided by 12 (feet vs inches). That should give me a reading on the wrench of 11.6 (which is 15Nm).
The dumbbell was supposedly 4kg (hmm should have been 6 to be in ballpark) so I took it to work to check that. 3.9Kg.

I did the formula with the conversions, and even sense checked it in Nm (have to convert KG m by 9.8). 15Nm on the wrench was barely over 10 being applied.
Any way I did it, my Sacred Reader of Truth was Torquing Bullshit. By 1/3rd!

And that is why for between 0-30 years I have seemingly been under torquing important bolts.

My ‘Good’ Torque Wrench was Good because I bought it and it was an obvious step up from the long bar with a moving pointer I had when I was 20. I owned it so it must be correct says the disillusioned fettler. I mean I think it was German. . .
I watched a few YouTubes to confirm my measurements and saw that their Wrenches had calibration screws along the shaft. Mine does not.

Oh well, new wrench time. Had to order in one that does the range I want( covers 7-110Nm - fine for bikes). But I will be checking it out of the box and every year or so. Don’t trust Nuthin.

pete376403
3rd July 2025, 17:11
Now you have me doubting my torque wrench - Snap On, 3/8 drive, always lives in its plastic case when not being used, always wound back to 0.

F5 Dave
3rd July 2025, 19:11
Find a weight or two circa 6-7kg combined or more, that you can attach to a clothes hanger.

neels
4th July 2025, 09:05
What make of torque wrench? Some are adjustable, some are not, and on some it's pretty well hidden.

Some are not that well designed and can accidentally be uncalibrated if the wrong bit is unscrewed. They do wear over time, particularly the type that have a square block between the head and adjustment mechanism, when the corners get worn they 'break' more easily.

In a previous life I worked in a calibration lab, it was not uncommon to see torque wrenches that were delivering much less than what they were set to. One that I checked was doing about a quarter of it's setting, which explained for the owner why the flywheel fell off his engine when the bolts had been torqued to the correct setting on his wrench. Most people with experience and a reasonably calibrated arm would probably notice it wasn't right at that point.

The methodology you've used is exactly how the test gear was verified between calibrations, back to first principles with a known length bar and known weight to check it gives the correct reading.

SaferRides
5th July 2025, 01:26
I’ve had my Torque wrench 30 years. I’ve never abused it, always wound the tension off after use. It is the Holy Teller Of Truth when it comes to tightness.

And to be honest I don’t use it on everything, I’ve ‘decided’ that I have a pretty good feel for how tight and dangerously excessive. Mechanics will laugh or agree in secret of their own amazing ability, unlike those other losers who strip every third bolt.
My elbow clicks at the right Torque :)

Always used it on cranks and head-nuts though.

Triple clamps are a good area for caution. Too many torques can squeeze ally uppers affecting action, apparently. The lower clamps are set not that tight really.
In fact, it was this area that I hand tightened and then reached for the Torque wrench. I didn’t have my manual or phone on me, so I wrote a piece of tape on the Tank to recheck everything attached to the forks. I then read the suggested settings off the Beta which are actually screen printed on the triple clamps (cool huh?). I figured then would be in the low side of things being a very light bike. It would be more for the Adventure bike so it was a safe setting for now.
The Torque wrench clicked straight away meaning that my hand guess was either bang on, or too tight. Hmm.

So I found a dumbbell and a coat hanger, put a sacrificial bolt in the vice and adjusted the wrench to an arbitrary setting, fairly low. The weight was too heavy and set it off even when adjusting it down to lowest 10Nm. So I adjusted it to 15 and moved the coat hanger up the handle so it just clicked, and 2mm up it wouldn’t. So I marked where it would. I measured to the centre of the square drive.
Working in foot pounds and inches it was Length in Inches and weight of dumbbell divided by 12 (feet vs inches). That should give me a reading on the wrench of 11.6 (which is 15Nm).
The dumbbell was supposedly 4kg (hmm should have been 6 to be in ballpark) so I took it to work to check that. 3.9Kg.

I did the formula with the conversions, and even sense checked it in Nm (have to convert KG m by 9.8). 15Nm on the wrench was barely over 10 being applied.
Any way I did it, my Sacred Reader of Truth was Torquing Bullshit. By 1/3rd!

And that is why for between 0-30 years I have seemingly been under torquing important bolts.

My ‘Good’ Torque Wrench was Good because I bought it and it was an obvious step up from the long bar with a moving pointer I had when I was 20. I owned it so it must be correct says the disillusioned fettler. I mean I think it was German. . .
I watched a few YouTubes to confirm my measurements and saw that their Wrenches had calibration screws along the shaft. Mine does not.

Oh well, new wrench time. Had to order in one that does the range I want( covers 7-110Nm - fine for bikes). But I will be checking it out of the box and every year or so. Don’t trust Nuthin.What range is your torque wrench? I wouldn't trust any click / micrometer torque wrench below 20% of full scale. And they should be checked regularly.

I have two - a 3/8" W&B deflecting beam and a 1/4" click type because it's more accurate for low torques, like spark plugs. The 1/4" is used more often as it is surprising how many fasteners on a motorbike need less than 25 Nm.

I should check them against each other regularly...

Sent from my SM-S938B using Tapatalk

F5 Dave
5th July 2025, 09:12
I'll check what brand the old one is before I throw it away in disgust. Actually, I might do some more tests through the range first.

The new one is a Holy Toledo ( OK, I made the first bit up in deference to Klinger on M.A.S.H). It is probably fairly generic and has a bung halfway up, which will be the calibration.

I'll test it with the same method, which is at a low setting.

It came in a case with a hand recorded calibration certificate with four measurements over 3 ranges. I'd like to open another to see if it is just a clever photocopy but it is probably genuine.

Says it's range is 7 to 110Nm. I probably won't use it above 50ish anyway.

Thanks for your insight neels, you're the closest to an expert I've met so thanks.

SaferRides
5th July 2025, 09:48
The new one is a Holy Toledo ( OK, I made the first bit up in deference to Klinger on M.A.S.H). It is probably fairly generic and has a bung halfway up, which will be the calibration.

I'll test it with the same method, which is at a low setting.

It came in a case with a hand recorded calibration certificate with four measurements over 3 ranges. I'd like to open another to see if it is just a clever photocopy but it is probably genuine.

My 1/4" came with a similar calibration certificate. It's a Taiwanese brand, King Tony?

Thanks for the thread, I've had the 1/4" for a while and should check it.



Sent from my SM-S938B using Tapatalk

husaberg
5th July 2025, 10:47
I’ve had my Torque wrench 30 years. I’ve never abused it, always wound the tension off after use. It is the Holy Teller Of Truth when it comes to tightness.

And to be honest I don’t use it on everything, I’ve ‘decided’ that I have a pretty good feel for how tight and dangerously excessive. Mechanics will laugh or agree in secret of their own amazing ability, unlike those other losers who strip every third bolt.
My elbow clicks at the right Torque :)

Always used it on cranks and head-nuts though.

Triple clamps are a good area for caution. Too many torques can squeeze ally uppers affecting action, apparently. The lower clamps are set not that tight really.
In fact, it was this area that I hand tightened and then reached for the Torque wrench. I didn’t have my manual or phone on me, so I wrote a piece of tape on the Tank to recheck everything attached to the forks. I then read the suggested settings off the Beta which are actually screen printed on the triple clamps (cool huh?). I figured then would be in the low side of things being a very light bike. It would be more for the Adventure bike so it was a safe setting for now.
The Torque wrench clicked straight away meaning that my hand guess was either bang on, or too tight. Hmm.

So I found a dumbbell and a coat hanger, put a sacrificial bolt in the vice and adjusted the wrench to an arbitrary setting, fairly low. The weight was too heavy and set it off even when adjusting it down to lowest 10Nm. So I adjusted it to 15 and moved the coat hanger up the handle so it just clicked, and 2mm up it wouldn’t. So I marked where it would. I measured to the centre of the square drive.
Working in foot pounds and inches it was Length in Inches and weight of dumbbell divided by 12 (feet vs inches). That should give me a reading on the wrench of 11.6 (which is 15Nm).
The dumbbell was supposedly 4kg (hmm should have been 6 to be in ballpark) so I took it to work to check that. 3.9Kg.

I did the formula with the conversions, and even sense checked it in Nm (have to convert KG m by 9.8). 15Nm on the wrench was barely over 10 being applied.
Any way I did it, my Sacred Reader of Truth was Torquing Bullshit. By 1/3rd!

And that is why for between 0-30 years I have seemingly been under torquing important bolts.

My ‘Good’ Torque Wrench was Good because I bought it and it was an obvious step up from the long bar with a moving pointer I had when I was 20. I owned it so it must be correct says the disillusioned fettler. I mean I think it was German. . .
I watched a few YouTubes to confirm my measurements and saw that their Wrenches had calibration screws along the shaft. Mine does not.

Oh well, new wrench time. Had to order in one that does the range I want( covers 7-110Nm - fine for bikes). But I will be checking it out of the box and every year or so. Don’t trust Nuthin.


I watched a video the other day and it turned out over time like 30 years the old rusty strain gauge torgue wrench was more accurate than what ever expensive new clicky one they tested it against. but it was a the net and one vs 2 so hardly scientific.
A lot of the fasteners at really mater were done with torques plus angle or other methods.
Factories tend to have really good GC torque systems measure it against them. Try one of them.

neels
5th July 2025, 13:34
The new one is a Holy Toledo ( OK, I made the first bit up in deference to Klinger on M.A.S.H). It is probably fairly generic and has a bung halfway up, which will be the calibration.
If it's this one, put some decent tape around where the end cap meets the main part of the handle, there's a threaded sleeve inside that acts on the spring which is the adjustment. If the end cap is accidentally unscrewed and the sleeve comes with it that's the calibration gone. If I remember correctly the adjustment part way along is the pivot point for the arm inside, which adjusts the linearity.
356403


I watched a video the other day and it turned out over time like 30 years the old rusty strain gauge torgue wrench was more accurate than what ever expensive new clicky one they tested it against. but it was a the net and one vs 2 so hardly scientific
The clicky ones will always have something that acts against a spring, and is therefore wearing every time you use it. The tension wrenches tend to stay in calibration unless they are overstressed or fail completely, the downside of most of them being that you have to be able to read the scale when you're using them.

Kickaha
5th July 2025, 16:25
The torque wrenches we used at work were meant to be calibrated I think every 600 clicks, they were a high use item and it was cheaper to just replace them every 6 months

F5 Dave
5th July 2025, 17:27
That looks right neels. Sorry, do you mean the silver knurled grip and the hex piece?

neels
5th July 2025, 17:53
That looks right neels. Sorry, do you mean the silver knurled grip and the hex piece?
Yep, the hex bit on the end is effectively a lock nut for the threaded sleeve that sets the spring tension inside the knurled handle, can come undone when the handle is being wound out and the sleeve can unwind with it affecting the calibration. A bit of fairly permanent tape around the join stops it moving.

F5 Dave
5th July 2025, 18:55
Cool thanks