FBinNY 

It's funny. I'm a long time jazz fan, and am asked that often.

Yes, I used to play, but no longer. I prefer to listen to talented players.

BTW, if you asked because I mention using sound, it's not hard to recognize hearing, ping, ping, ping, ping, ping, pung, ping, ping

pdlamb

I don't doubt that there are skilled wheel builders who don't use tensiometers, and I suspect some were trained even after 1981. Some (but not all!) wheels built by these people lasted for years. After 1981? It took a while for the idea of using a tensiometer to gain traction, and even longer for builders to start accepting a "need" for an expensive new tool. That said, I think there are three reasons to accept a tensiometer as a useful adjunct, or even foundational tool, for building or adjusting wheels today.

First, I suspect you have built hundreds or even thousands of wheels. I've built and trued maybe dozens. Short of dedicated training and working with masters of the craft to check intermediate works, a tensiometer lets an amateur like me to build or true wheels that work as well as a master of the craft, as adjudicated by durability on the road. Side notes: I've bought wheels from alleged wheel masters which start de-tensioning within a few months. After I've trued and tensioned those same wheels, they stay true untouched or with minor annual touch-ups for years and tens of thousands of miles. Unfortunately, that makes me question how to tell who really knows how to build a wheel. The "best wheel man in town" may be the one who can untwist a pretzel between Monday and Friday before it rolls into the rock garden on Saturday -- and gets bent and goes back to the shop next week, with no thought of durability or reliability over a longer term.

Second, in this day and age, a tensiometer is a way to communicate remotely. You can pick spokes and hear differences, but since I'm not in your shop, and since my hearing may be declining, you can't effectively show me the feel and sound of a well-built wheel. The quantitative nature of a tensiometer, effectively used, allows comparisons and instruction across the internet, or through print.

Third, since some wheels are being built with smart machines incorporating tensiometers, there's a possibility that a well-built wheel may be produced by a machine. It's not transparent to me where the cost line is, so if I buy a machine built wheel (because it's less expensive that its components), I can check it and correct it as necessary (see reason 1).

FBinNY 

You mischaracterize my "dislike" of tension meters. In fact, my objection is limited to a specific issue, namely the method of checking all spokes, plotting the info, and letting that drive the bus.

Not only is it much slower, but it causes folks to "overwork the dough". It's a poor substitute for good methology which can be taught and learned equally easily.

Earlier, I likened this to using training wheels. As long as folks rely on the method, they won't learn better, faster methods. Moreover, the common tension meters lack adequate repeatability, so they could lead folks astray.

That's not to say that tension meters have no place. Used as a QC tool to spot check tensions, and confirm that final tension is within goals, they serve a valuable function, regardless of builder experience.

As a side note, I have a personal objection. Over the years clients would object that the wheels I delivered weren't tight enough. Meters add to the mystique allowing folks to quantify and compare more easily. It's not a serious problem, which I address by asking if they want the wheel to my spec.or theirs, but it's an annoyance.

BTW, earlier in the thread there were posted 2 tension plots, ostensibly of finished wheels. Folks are free to judge the method by the results.

pdlamb

Got it, thanks for the clarification.

And, uh, yeah. (Do front wheels have NDS spokes?)

Ryan_M

Yes this is why I asked. I spin the wheel and ping the spokes and all of them sound the same. I can compare two spokes by pinging going back and forth a few times listening for the difference in pitch, but it will take a long time getting a feel for the state of a wheel only comparing two spokes at a time. Still, I am not confident in those results. Perhaps I'm a bit tone deaf. How do you do it without pinging spokes?

Unless I missed it, I think there's only been one finished wheel posted (not by me)?

FBinNY 

Not my charts. They could be mislabeled, or maybe NDS there meant not Disc side.

FBinNY 

Posts 27 & 45.

I only ping near the end to show true outliers. As I've said, I rely on good shop practice to prevent uneven tension, rather than trying to manage it downstream.

Looking at your chart, you should be able to hear the ones most off in either direction. If I had the wheel, I might have some sense based on nipple feel, but certainly not by remote control.

Since you made the chart, start with the worst loose and tight spokes, and correct them against their neighbors. Focus in getting more even tension within local areas, and the big picture will come together for you.

Ryan_M

Ahh... post #45 was me. Sorry for the confusion, I thought I had mentioned this was a "so far" state of affairs. It's only mid way tensioned and only starting to smooth things out, not at all a finished product. The initial intention was to show mpetry912 the graphs I'm working with to contrast with the software he's using - since I haven't seen software where I can define my own spring constant. Cheers.

FBinNY 

OK, so set the elbows and uniformly add tension BEFORE making any adjustments.

FBinNY 

I'm not familiar with how you were taught, so have a question.

Is it SOP to measure tension so early?

Doing so, and tweaking accordingly is probably counter productive. There are variables that cause uneven tension which will resolve later, unless you "correct" based on the false data.

Do not try to correct tension until after elbows are set, and the wheel is reasonably true at 80% or so of target tension.

Ryan_M

I wasn't really taught. Only going by what I've gleaned off the internet, and by helpful people like yourself.... of course some trial and error too!

No, no it isn't. The first two wheel sets I built I went for true first, then had to spend quite a bit of time tweaking tension to get it ballanced well and under 10% deviation. Since I now have a tensionometer that is fast and accurate (I can measure and enter data in under 4 minutes), this is an experiment to see what if I focussed on spoke tension earlier in the build. I intially laced and brought up some tension (~30kgf) only by counting equal number of turns - plus an extra half turn on the DS to set dish closeish. This is when I first measured tension and it was fairly erratic at approx. 30% deviation IIRC. Focusing on getting tension closer to equal at this point improved and smoothed out the radial true and didn't make the lateral true any worse. I was mostly 'getting my house in order' before adding more tension. When I added more tension (~60kgf) things seemed to calm down a bit more, radial true improved slightly again, lateral true seemed unchanged. It's out but nothing funky and should be easy to get in line. At this point I added more tension to get to ~90kgf. I haven't measured anything yet but I'm super curious to see where things lay.

FWIW they're straight pull spokes. Yes, now I think I will focus on getting true near final and tensions evened out better before adding the final bit of tension. Thanks!

FBinNY 

Part of the problem is that you're trying to build a house without a decent foundation.

Here's some critical info that may help.

1 the rim's location is determined by the spokes' lengths (hub to nipple), not their tension.
2 spoke length changes rim position differently radially vs. wobble. ------ Every full turn of the nipple moves the rim about 0.5mm radially, and about 8-10mm sideways.
3 early on, there are low strength variables, mainly related to the elbows that can seem significant at low spoke tensions, yet are nearly insignificant compared to final tensions.

So, focusing on length, trying to be accurate to within 1 full turn will produce a wheel with radial true within LT 1mm UNLESS, you muck it up by "correcting" the false errors that appear early on.

Short version --- use good process and TRUST it to produce good results. Fine tune only near the end.

79pmooney

Yes, but it's the right side! NDS for front wheels - non disc side. Or on my rim braked bikes, both sides.

Edit: I see FBinNY beat me too it. Not surprised.

Ryan_M

Part of the problem? Is there a problem I missed? Not sure what you're referring to. I'm pretty happy with how things are progressing despite the alternative method. What specs do you consider adequate? What do you build to?

FBinNY 

Except that I was just guessing.

FBinNY 

Sorry if I've offended you. I wouldn't have posted except that you keep asking for help.

FWIW I'm more focused on process than results. There are countless ways to end up where you want to go. I'm interested in getting there quickly, without having to climb mountains or ford streams along the way.

As to specs. I don't have rigid tension specs because rims vary. On the few that I've been curious enough to check, I've come out within 10% best to worst.

My general rule is to call it quits when the joint or other imperfection becomes the limiting factor.

Ryan_M

I am not offended. And I wouldn't keep asking if I didn't want to hear what you have to say. However, I don't view this as me asking for help, but more about wanting to hear you point of view on things.

You didn't answer my question though... What are the specs you build your wheels to? I'd like a target to aim for

[edit] I missed the last bit of your response... just so I understand you correctly, you're saying when you've bothered to check you're within 10% deviation for spoke tension and that's good to you, yet I'm part way through a build at 13% deviation and you say it's poorly built? Did I misinterpret anything? [/edit]

FBinNY 

I answered. The specs depend on what the rim allows. It's not a specific value, but more of a compromise between alignment and tension.

To give an example. Better rims are shipped as cylinders, either shrink wrapped or boxed. The middle ones arrive in pristine conditions, but the ends often suffer transit damage. They're still OK, but can never have uniform tension and be straight.

At some undefined point I decide it's as good as it's going to get and call it quits.

If you want a goal, shoot for within 10% TIR, but be willing to accept a few outliers if necessary.

Ryan_M

No you didn't. 10% is a pretty loose spec. What about lateral and radial true?
​​​​​

FBinNY 

That was a suggestion for you to shoot for. Otherwise, see post #10.

Ryan_M

Yeah, just you've been vocal about me doing it wrong, yet you've been ambiguous about what you build to. You've pointed out I have a problem. You stated to aim for 10% deviation on spoke tension but accept a few outliers, then stated my wheel (part way through the build) is poorly built at 13% tension deviation including the outliers. This would imply my wheel is built at least as good as your's? Is it? Why are you critical (or hypocritical) of my numbers if you don't share yours?

I have no doubt you can build wheels well that will have a long and reliable service life. However, the fact that you've never plotted the data on your wheels suggests you really don't know how good or mediocre your wheels are. It doesn't appear you have a leg to stand on to criticize anyone. If you put up some data to support your alleged abilities then I'd be happy to be proven wrong.

[edit]Here's me talking about numbers, and me not sharing the latest. Currently printing parts to measure this better but lateral true as best as I can measure now is 0.2mm p-p, radial is 0.35mm p-p. The radial bugs me, it should be ok but seems bumpy. Spoke tension is 10% on the low tension side and 7% on the high tension side (~110kgf), including the outliers. Likely tweak a bit but I think I'm pretty close to done.[/edit]

FBinNY 

You omit a critical difference. You came here asking for help, I didn't.

If you don't want my help, just ignore it. OTOH, I'll spare you that effort by not offering it in the future.

L134 

It seems to me you are hyperventilating about differences that really don't make any difference. Read some books about it and decide for yourself. I think you'll find the "experts" don't agree with each other and therefore you will never find the answer you want to find. Find whatever expert you want to believe, go with it and be happy.

razorjack

Hello,

What's the recommended spoke tension for rear wheel? Hope hub 148x12 (disc), DT EX 511 rim 29" 32h. (max tension 122 kgF)
Around 100-110kgF on 'steeper' side? DS at a back and NDS/disc side on a front ?

FBinNY 

Correct spoke tension isn't about the hub, but about the spokes themselves, and to a lesser extent the rim.

Assuming 32 or 36 14g (2mm) butted spokes, I'd consider 90-105kgf just about right. The left side tension will be whatever it ends up being with correct dish. You can roughly predict that based on the ratio of L/R center to flange distances, ie. CTFs = 56/32, left tension will be 57% of right tension.

With high dish wheels I work backward, shooting for left tension of 55-60kgf, and right to be whatever is needed. Also, I prefer to use thinner spokes on left ( and usually front) to lower the minimum tension, so I can keep the right side slightly lower.

If using fewer, or heavier spokes the ideal tension will be higher.

Overall, you target something between the minimum tension based on the spoke gauge and a maximum tension based on the rim.

Because there's no dish (or less with disc brakes) front b tension is much more forgiving, so 75-90kgf is fine.