Over tightened spokes

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Mr Tom
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Over tightened spokes

Post by Mr Tom »

So a few days back I built a wheel for the second time. I was very patient and prepared everything, watched some videos, checked my 'The Bicycle Wheel' book and everything. Anyway, I laced up the wheel fine, but as I began to tighten it I found the spokes were getting tight way before they were properly into the nipples. I should have stopped and had a cup of tea, but I was in a hurry and ended up continuing, not going crazy, but tightening fairly firmly. Once the spokes felt really firm I stopped and finally realised what had happened, I'd put different box of spokes on top of the ones I was meant to use, and had laced them up instead.

Before I loosened the wheel I checked the tension and most of the spokes were at or below 28 on my Park Tool meter, which with 2mm spokes would give 173kgf. Some were as tight as 31 on the meter, which is off the chart on the conversion table.
I just wondered if it's possible to accurately say if I will have damaged the rim, spokes or hub tightening to high, or if it can go way higher before it's likely to do any damage. The rim is a Rigida Sputnik so pretty tough, and the hub is a Sturmey Archer Steelite. I hope this makes sense, still very much a beginner to building wheels!
rogerzilla
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Re: Over tightened spokes

Post by rogerzilla »

Very unlikely. I have wheels where the RHS is at 170kgf. The most likely outcome would be rim cracking around the holes after many miles.
Jodel
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Re: Over tightened spokes

Post by Jodel »

I'm no expert wheelbuilder, but I would be very surprised if you had any problems. My Park Tool meter is great for checking that there is consistent tension from spoke to spoke, but it is way off in terms of measuring the actual spoke tension. For example, a reading of 28 on my Park meter is an actual value of 130kgf not 173kgf. (Sapim Strong spokes).

I made up a rather heath-robinson spoke test rig with a digital strain gauge to check my Park meter and I found it to over-read significantly. As I say, it's very consistent in its readings, but the absolute values are not accurate.

I ended up recording a range of Park Tool readings in a spreadsheet and 'translating' the actual tensions against the Park values.
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531colin
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Re: Over tightened spokes

Post by 531colin »

Tom, this doesn't smell right to me.....unless maybe you have hands like bunches of bananas?
In short, I have never, ever been able to achieve the sort of tensions you are talking about.
For you to get there accidentally is simply beyond belief, and if the nipple threads aren't fully engaged I would expect the threads to strip before you got to those tensions.
Firstly, check that you are reading the tension chart right, as you know the spoke thickness governs what deflection you get for a particular tension. Check the feel of a wheel you have built against a "known good" wheel.
Secondly, I have known whole manufacturing runs of those Park gauges to be sent out wrong.....the manufacturer changed the spring gauge and didn't alter the calibration. It was bedlam, we had people who built wheels at home sending in wheels which were way too slack, which I had to correct, and we had to recall any gauges we had sent to customers. (There was a thread on here where somebody bought a gauge, which was wrong....I know that because he sent it to me. He sent it back to the retailer, who sent him a "new" gauge......only he had surreptitiously marked "his" gauge somewhere, so he knew they had simply sent back the dodgy gauge!)

....there you go, Jodel obviously lived through this as well!
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531colin
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Re: Over tightened spokes

Post by 531colin »

Jodel wrote: 25 Jun 2022, 8:54am I'm no expert wheelbuilder, but I would be very surprised if you had any problems. My Park Tool meter is great for checking that there is consistent tension from spoke to spoke, but it is way off in terms of measuring the actual spoke tension. For example, a reading of 28 on my Park meter is an actual value of 130kgf not 173kgf. (Sapim Strong spokes).

I made up a rather heath-robinson spoke test rig with a digital strain gauge to check my Park meter and I found it to over-read significantly. As I say, it's very consistent in its readings, but the absolute values are not accurate.

I ended up recording a range of Park Tool readings in a spreadsheet and 'translating' the actual tensions against the Park values.
Did you write it up here?....a link would be a bonus!
Jodel
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Re: Over tightened spokes

Post by Jodel »

Did you write it up here?....a link would be a bonus!
Colin, I think I read various comments about the Park meter on here and that was what prompted me to make up my own 'calibration' rig.

What really made me suspicious of the readings was when I checked a set of wheels I'd had built by Spa some time ago - they were still completely true, but reading way over the recommended tensions. I trust Spa to get it right more than Park :) .
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531colin
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Re: Over tightened spokes

Post by 531colin »

A couple of threads....I think there will be more if anybody has the skills and patience to search!
viewtopic.php?p=650682&hilit=Park+tension+gauge#p650682
viewtopic.php?f=5&t=54115&hilit=park
TheBomber
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Re: Over tightened spokes

Post by TheBomber »

Jodel wrote: 25 Jun 2022, 8:54am My Park Tool meter is great for checking that there is consistent tension from spoke to spoke, but it is way off in terms of measuring the actual spoke tension.
Mine is way out too - received as a present in 2020. Inspired by posts on here I built the jig for calibrating for a particular spoke brand and dimensions as a lockdown project. This is a more accurate than a generic chart (even if it had been correct) as I’ve noticed that one brand’s 1.8mm spokes isn’t the same as another anyway.
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Mr Tom
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Re: Over tightened spokes

Post by Mr Tom »

531colin wrote: 25 Jun 2022, 8:57am Tom, this doesn't smell right to me.....unless maybe you have hands like bunches of bananas?
In short, I have never, ever been able to achieve the sort of tensions you are talking about.
For you to get there accidentally is simply beyond belief, and if the nipple threads aren't fully engaged I would expect the threads to strip before you got to those tensions.
Firstly, check that you are reading the tension chart right, as you know the spoke thickness governs what deflection you get for a particular tension. Check the feel of a wheel you have built against a "known good" wheel.
Secondly, I have known whole manufacturing runs of those Park gauges to be sent out wrong.....the manufacturer changed the spring gauge and didn't alter the calibration. It was bedlam, we had people who built wheels at home sending in wheels which were way too slack, which I had to correct, and we had to recall any gauges we had sent to customers. (There was a thread on here where somebody bought a gauge, which was wrong....I know that because he sent it to me. He sent it back to the retailer, who sent him a "new" gauge......only he had surreptitiously marked "his" gauge somewhere, so he knew they had simply sent back the dodgy gauge!)

....there you go, Jodel obviously lived through this as well!
Hey Colin,

Thanks, I think I must have been doing something wrong with my measuring. I definitely didn't go that crazy on them! I'll have a look at the gauge and go over everything again on the chart. it's all good learning experience!
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simonineaston
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Re: Over tightened spokes

Post by simonineaston »

Just to throw a curve ball at the topic, I've built several sets of wheels over the years, all of which have performed as intended, but never used any tools other than a spoke key / screwdriver.
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Mike Sales
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Re: Over tightened spokes

Post by Mike Sales »

simonineaston wrote: 25 Jun 2022, 12:16pm Just to throw a curve ball at the topic, I've built several sets of wheels over the years, all of which have performed as intended, but never used any tools other than a spoke key / screwdriver.
Me too. I have built a lot more than several with the same tools as you.
With modern, high number of sprocket cassettes and hence extreme dishing, the difficulty I find is getting the drive side spokes tight enough to allow enough tension on the LHS spokes. It is physically difficult to wind up the tension, but this is the chief problem, not breaking spokes
I mean breaking spokes immediately of course, because such imbalanced wheels cannot be reliable in the longer run.
Last edited by Mike Sales on 25 Jun 2022, 1:10pm, edited 2 times in total.
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simonineaston
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Re: Over tightened spokes

Post by simonineaston »

extreme dishing
That's good point - mine have always been either on ighs or else freewheels / low count cassettes...
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
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Mr Tom
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Re: Over tightened spokes

Post by Mr Tom »

I checked on my Spa built back wheel which has Sapim strong on the drive side and some were up to 30 on the metre, so maybe it is out of adjustment.

The front which are Sapim Race were right at the top of the scale at 25 / 167kgf
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Mick F
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Re: Over tightened spokes

Post by Mick F »

simonineaston wrote: 25 Jun 2022, 12:16pm Just to throw a curve ball at the topic, I've built several sets of wheels over the years, all of which have performed as intended, but never used any tools other than a spoke key / screwdriver.
Same here.

27" wheels, 700c wheels and 406 wheels, not to mention the front wheel for the Raleigh Chopper to fit a roller brake.
The rear wheel on 10sp Campag Mercian is highly dished, and I built it ........ and the previous one or two ........... with plain gauge on the drive side, and double butted on the non-drive side.

Screwdriver, and spoke key and used the bike frames ..........and only latterly bought a wheel-jig.
Mick F. Cornwall
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531colin
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Re: Over tightened spokes

Post by 531colin »

I built plenty of wheels without a tension gauge, and many more using a gauge.
I'm not only more accurate with the gauge, I'm quicker as well......the secret is to use the gauge throughout the build....that way you quickly get to a wheel thats correctly dished (or centred) and there are no nasty surprises by way of wildly wrong tensions at the end.
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