Wheel building

[redir]

How do you know what tension should be for any specific wheel/hub/spoke system? To the hubs have the recommended tensions or the rim manufacturer maybe?

[marciero]

Originally Posted by David in Maine

Ok, I found a Park tensiometer that I can borrow for the build. Now I can call my self a wheel builder

David

Not necessarily. Just because wheelbuilder -> tensionmeter does not mean that the "converse" is true ; )

[marciero]

Originally Posted by oldpotatoe

errr, without a tension meter, how do ya know the other wheel is 'properly tensioned'??

geez, I am not a guy who values speed when building a wheel but I'm sure not gonna build a wheel, then start plucking spokes, compare to another wheel and try to finish the thing..buy a tension meter, there are some good, inexpensive ones out there, and finish the wheel..

Yes, you will have to have a wheel in your quiver that has at some point in its life seen a tensiometer. Once you get up to tension you only need to checkthe reference wheel once or twice, and only one or two spokes on each wheel. Maybe a few more if there is variation.

But my remarks were mostly about relative tension. I would think plucking would be much faster for that than using a tensiometer. I would also bet that it would be about as accurate-especially given the indirect method of measurement that tensiometers use to measure tension.

It's not hard to check. Frequency goes as square root of tension so a 1% difference in tension between two spokes-say 100 kg and 101 kg-would result in frequency ratio (the interval corresponds to one freq divided by the other and not the difference) of approx 1.005. A diatonic semitone-two adjacent keys on the piano- is 2^(1/12) approx 1.029, which is bigger, but most people can hear way less than that, easily 1/5 of that, so 1.029^(1/5) approx 1.006. So we are really close here. Are tensiometers accurate to 1%?

[berserk87]

Plucking seems like a pretty random way to check for spoke tension. Where do you pick to pluck? Won't the location vary per spoke, which could impact the tone? Plus, you have to recall your memory of the last plucked spoke and rely on your brain to compare. Or keep plucking back and forth until you feel like you have it. There are better ways to play the harp.

Have you ever seen "The Voice" or "America's Got Talent"? Some folks are pretty tone deaf.

If you want to go one further, why use a truing stand to assist with a build? You could eyeball the wheel I reckon. In fact, why use a spoke wrench? You could get by, clumsily, with a pair of pliers.

If there's a reliable tool to make the job easier and more uniform, why not use it? Is cost the deterrent? I'm thinking that it's worth the investment if you are spending the time and money to build wheels. Wheels, inherently, are not inexpensive. Even the cheap ones will run you a few hundred bucks.

And dude, come on:

"It's not hard to check. Frequency goes as square root of tension so a 1% difference in tension between two spokes-say 100 kg and 101 kg-would result in frequency ratio (the interval corresponds to one freq divided by the other and not the difference) of approx 1.005. A diatonic semitone-two adjacent keys on the piano- is 2^(1/12) approx 1.029, which is bigger, but most people can hear way less than that, easily 1/5 of that, so 1.029^(1/5) approx 1.006."

It's worth spending the money to not have to try and comprehend this and make my brain hurt.

[David in Maine]

Originally Posted by marciero

Not necessarily. Just because wheelbuilder -> tensionmeter does not mean that the "converse" is true ; )

Yes, I totally realize this hence the dancing banana!

[marciero]

Originally Posted by berserk87

Plucking seems like a pretty random way to check for spoke tension. Where do you pick to pluck? Won't the location vary per spoke, which could impact the tone? Plus, you have to recall your memory of the last plucked spoke and rely on your brain to compare. Or keep plucking back and forth until you feel like you have it. There are better ways to play the harp.

tone and pitch are different things. What we call pitch is actually frequency and does not depend on where you pluck. Try it on a guitar- or a harp!

Incidentally, Pythagoras actually studied this stuff. Motivated by the sound of blacksmiths pounding on anvils. At least that is the folklore. He supposedly originally though that the pitch might depend on how hard they were hitting (it's not).

[David in Maine]

I'm a banjo player so I'm very used to listening for intonation (or lack thereof!). I wonder if my electronic clip on tuner will register spoke pitch. I'll have to give it a try!

[Tony T]

How does 'tone' determine the tension? Yes, it can determine equal tension, but how can it determine if the spokes are over/under tensioned?

[ultraman6970]

There is a table moving around with studies about tension- tone... even there's a sonic like tensionmeter app moving around aswell. How accurate is? no clue. But the fomulas relating tension and tones had been around for the longest time.

Google, you will find them.

[Jeff Borisch]

Checking pitch is handy to know which spoke out of the group of 3-5 needs to be tightened or loosened more than the others. It's not always the one closest to the middle of the blip. Once I started doing this it's sped up my builds immensely.

Giving the spoke a gentle tap with a spoke wrench gives the clearest tone. Tap it in the center of the longest segment.

As for tension overall, with a little experience, old school 32-36 hole wheels are easy to build to an acceptable tension without a tensiometer. It's better if you have one that you trust, but you really don't need one.

Building to higher tensions and with fewer spokes, I need a trusted tensiometer.

my $0.02

[David in Maine]

Interesting perspective here:
https://www.wheelfanatyk.com/blog/wh...9-tight-right/

Wheelfanatyk store sells both tensiometers and banjo picks--I think Jeff's idea sounds helpful.

David

[Ronsonic]

Originally Posted by David in Maine

Well, I am a musician!

I can tension a banjo head, I can tension a wheel. Can also tune an autoharp. I got this.

[oldpotatoe]

But my remarks were mostly about relative tension. I would think plucking would be much faster for that than using a tensiometer. I would also bet that it would be about as accurate-especially given the indirect method of measurement that tensiometers use to measure tension.

Not trying to argue, but 'plucking' with a tension meter checked wheel..why not just use the tension meter. 1.85 for my spokes, DT dial meter..takes no time at all..as I mentioned, time means nada, but meter sitting there..onto spokes, done..The idea of pluck this spoke, then pluck that spoke, trying to see if it is.

Frequency goes as square root of tension so a 1% difference in tension between two spokes-say 100 kg and 101 kg-would result in frequency ratio (the interval corresponds to one freq divided by the other and not the difference) of approx 1.005. A diatonic semitone-two adjacent keys on the piano- is 2^(1/12) approx 1.029, which is bigger, but most people can hear way less than that, easily 1/5 of that, so 1.029^(1/5) approx 1.006. So we are really close here. Are tensiometers accurate to 1%?

HAHA, YGBSM...like I said..just pull out the tension meter and check the dern spokes..I have NEVER worried about diatonic semitones...

If you build a wheel that way and get good results, good on ya but I'll stick to the DT meter, grazie..

If there's a reliable tool to make the job easier and more uniform, why not use it? Is cost the deterrent? I'm thinking that it's worth the investment if you are spending the time and money to build wheels.

No kidding..'New Park tensionmeter, nice wood..doesn't transport well tho..

[marciero]

Originally Posted by oldpotatoe

Not trying to argue, but 'plucking' with a tension meter checked wheel..why not just use the tension meter. 1.85 for my spokes, DT dial meter..takes no time at all..as I mentioned, time means nada, but meter sitting there..onto spokes, done..The idea of pluck this spoke, then pluck that spoke, trying to see if it is.


HAHA, YGBSM...like I said..just pull out the tension meter and check the dern spokes..I have NEVER worried about diatonic semitones...

Ha! Had to look that one up! As far as speed, I only check a reference wheel once or twice- after I've got the new one mostly tensioned. Plucking one or two spokes on each wheel gives immediate indication if they are close. Typically the new wheel can increase tension and I tighten a bit, final true and am good. You dont need to know any acoustics or music theory! (Call me naive or worse but in fact I only ever thought people used tensiometers for final check of tension and not for uniformity.) But I am convinced I do need to check out one of these things, if only to test my claims. I've sort of been meaning to get one. And now I have a cracked rim to replace... But I challenge you also, and any other tensio-philes, on your next build, when checking even-ness of tension and, say, your tension meter indicates a spoke under or over tensioned compared to others. Just try plucking to see if your ear can hear the difference your tensiometer indicates. My guess is that you will be able to hear the difference.

[cash05458]

"Pythagoras actually studied this stuff."

This one made me chuckle...Pythagoras actually stole a lot of his ideas from his mentor Anaximander...and it is well known Anaximander was a big fan of using tensionometers when building his wheels... so there...