# Newb QUestion - Spoke Tension Specs?



## ibericb (Oct 28, 2014)

*Newb Question - Spoke Tension Specs?*

Reading Musson's discourse about tensionmeters and spoke tension alerted me to the fact that different rim / wheel manufactures vary appreciably in their recommended spoke tensions. So I went an did some looking, and was surprised (as a newb would be) by the differences I found. I'm 

My search so far has included wheels/rims and spoke tension specs from Mavic, Stan's, DT Swiss ,  and others summarized by Park Tool (Bontrager, Campy, and Shimano)

I looked for patterns or tends based upon rime size (ERD) or weight, and couldn't find anything reliable. Campy seems to be the lowest, DT Swiss notes only a maximum tension, and Bontrager, Mavic and Stan's are all over the map. 

So as an aspiring DIY wheel builder I am befuddled. What do the experienced masters of wheel building advise newbs like me looking to get it right?


----------



## robt57 (Jul 23, 2011)

You may have seen this in other threads here, which is where I first saw it.
If not, read it, maybe a little insight shall be shed on you on some aspect. The notes on tension a good point. well a point

Wheel Building Tip No. 12 - Tuning the Ride - Wheel Fanatyk


It is all the internet though.

Dr. OCTTO says:	
November 23, 2011 at 10:00 pm

Hi Ric,

Regarding point (4), spoke tension (assuming a metallic wire spoke) cannot affect ride.

As you allude to in point (2) each spoke is a spring with a constant spring rate that depends on the spoke gauge (or minor spoke gauge on a butted spoke). This means that spoke stiffness cannot vary with spoke tension, because the stiffness (i.e. spring-rate) is constant.


----------



## ibericb (Oct 28, 2014)

I linked that same Tip yesterday in another thread. Yeah, I get the point about tuning, for what they may be worth relative to tires, rim design, etc. But, most of the specs I've seen are ranges, and all suggest a max that often less than the 125kgf I see cited repeatedly. So while I appreciate the choice/tune aspect, I'm still baffled a bit about setting a target.


----------



## robt57 (Jul 23, 2011)

I did not go back to see who had linked it.

I get this argument with folks all the time. They say I could not feel the windup in wheels with radial non drive rear wheels. I am sure I do and in fact do not ride them. I know what I feel. I know that the tire/size and pressures yada make the biggest difference. I can feel the difference of spoke ga in rear wheels, I do not give a **** who say I can not. My first road disk wheels that came on a Porprad I could feel the wind up and down. The wheels I just built for my Disc Roubaix I do not feel it. Probably why the new stuff is all 135mm not 130mm like the Proprad was.

But sometimes what you think you notice, the reason you perceive it 'that is', is not the actual reason for it.  It does not mean you do not perceive it or it is you imagination. I can tell the difference between a rear wheel wind up and a low tire pressure mushing for example. At least I perceive that I do. 

I know Dr. Otto make the point, I find lighter ga wheels springer, he appears to claim I could not. If a lighter ga spoke makes a wheel less stiff, how is that not going to effect the ride?? You are not always gong perfectly straight and on plane.


----------



## Peter P. (Dec 30, 2006)

The way I determine maximum spoke tension is not through measuring a number but through a "craftsman's feel".

That said, I do own a tensionmeter and use it to check tension but I do not seek to reach a particular number.

Here's how I do it:

When a wheel is reaching maximum tension, I will notice the spokes begin to twist and creak as I turn them. I listen, and I FEEL the spokes as I turn them by squeezing the spoke between the fingers of my free hand. When I begin to feel the twisting and just begin to hear the creaking, I back off maybe a quarter turn and seek to increase tension no higher.

My logic is, when the creaking and twisting begin, the spokes are nearing their elastic limit and the rim will not compress any further under spoke tension. The first to break (and I have done this during wheel builds in my youth) is the spoke hole.

Using this method has not let me down in 30+ years.


----------



## ibericb (Oct 28, 2014)

I won't doubt what you perceive, or what you believe it is due to. There are so many variables in wheel and tire combinations, and sensitivity awareness between folks that I believe about anything is possible. That said, it doesn't do much for helping me understand how to arrive at a target tension, much less a max or min for wheels I intend to build. 

Maybe another way of asking the question is what did the various rim/wheel manufactures consider in arriving at their specifications, and how were those spec determined? There are some significant differences even within an OEM. As one example, consider just this from Mavic:

Askium 12: Front 80-90 kgf / Rear DS 150-165 kgf
Ksyrium SLR: Front 110-130 kgf / Rear DS 90-110 kgf

How were those specific numbers determined as the appropriate ranges?


----------



## ibericb (Oct 28, 2014)

Here's an expansion on spoke tension by Hjertberg - it's Tip No. 19 in the same collection. 

His marking of 100 kgf fits all the front wheel spec ranges I've seen, except for all f the Campy and a couple of Mavic specs where it would be beyond the upper spec limit; it would be below the minimum DS rear spec for a number wheels each from Mavic, Bontrager, Campy, and Shimano specs.


----------



## ericm979 (Jun 26, 2005)

You need the tension high enough that spokes do not completely detension as the wheel flexes. The rim will flatten slightly where the tire touches the ground, and the wheel will flex to the side when you pedal standing up. Generally, about 55-60 kgf is enough on most wheels and rims. When a spoke detensions, it flexes at the elbow. Eventually the spoke breaks at the elbow. (or the nipples loosen!)

On the front getting above that tension is easy. I shoot for 90 or so on the front. On the rear NDS it's not so easy due to wheel dish. I find that the DS needs to be about 120kgf to ensure that all the NDS spokes are at 55 or higher (there will be some tension variation due to truing). If I can get to 130kgf that's better. Different flange geomtery will affect the NDS/DS tension ratio, as will off center rims.

I am hard on rear wheels- I do a lot of climbing and lots of steep grades in low gears, which puts a lot of torque through the wheel. I do a lot of that climbing standing, which stresses the wheel latrally as well as torsionally. Someone who was not as hard on wheels could probably make successful wheels with slightly lower NDS tension.


----------



## robt57 (Jul 23, 2011)

ericm979 said:


> I am hard on rear wheels- I do a lot of climbing and lots of steep grades in low gears, which puts a lot of torque through the wheel. I do a lot of that climbing standing, which stresses the wheel latrally as well as torsionally. Someone who was not as hard on wheels could probably make successful wheels with slightly lower NDS tension.


Have you tried lighter ga. spokes in the non drive side? Since my first build in the 90s I have been using 14/15 drive and 14/17 non drive.

The SL23 set I build the other day [got in one ride thus far] is All 14/17 except drive trailing rear which are 14/15. All Alloy nips too except those 7 pulling spokes are brass nips [28 spokes front and back]. Looking forward to putting some miles on them to see how they last/behave.  They are nice light snappy feeling.


----------



## ibericb (Oct 28, 2014)

robt57 said:


> Have you tried lighter ga. spokes in the non drive side? Since my first build in the 90s I have been using 14/15 drive and 14/17 non drive.


Okay, I'll show my ignorance. What's the difference or advantage of a thinner spoke on the NDS if the issue is spoke tension? Shouldn't the tension (total force as in kgf) be the same, regardless of spoke cross section?


----------



## Peter P. (Dec 30, 2006)

ibericb said:


> I won't doubt what you perceive, or what you believe it is due to. There are so many variables in wheel and tire combinations, and sensitivity awareness between folks that I believe about anything is possible. That said, it doesn't do much for helping me understand how to arrive at a target tension, much less a max or min for wheels I intend to build.
> 
> Maybe another way of asking the question is what did the various rim/wheel manufactures consider in arriving at their specifications, and how were those spec determined? There are some significant differences even within an OEM. As one example, consider just this from Mavic:
> 
> ...


The hub builders have to consider the tensile strength of the material at the spoke hole.

The rim manufacturers have to determine the strength of the aluminum or carbon at the spoke hole.

A spoke's tensile strength vastly exceeds the tensions it is wrenched to in a finished wheel. Spokes almost always fail due to long term fatigue, so don't even bother to consider them when thinking about wheel tension.

Mavic is an exception because THEY are responsible for all 3 components in the wheel.

Why the variations? Because in order for the wheel to be true and round, all the spokes will not be the same tension. My experience says the Mavic range variations tend to match what I see in a finished wheel build. I will admit that I can typically cut in half the variations in spoke tension or in other words, build a wheel to tighter tolerances than the variations Mavic specs, but I'm not building wheels in a production environment so I can afford to take the time to wring out the extra percentages.

The high end numbers Mavic publishes likely are near the limit for each wheel before something cracks but I'm sure there's some fudge factor added in.

Hope that helps.


----------



## robt57 (Jul 23, 2011)

ibericb said:


> Okay, I'll show my ignorance. What's the difference or advantage of a thinner spoke on the NDS if the issue is spoke tension? Shouldn't the tension (total force as in kgf) be the same, regardless of spoke cross section?



As I understand it, thinner ga need more tension to do the same job. Thus on the rear dish it allows for the NDS spoke to be closer tension to the drive side than the same ga spokes on both sides. And in fact on my wheels built this way this is the case.

In addition, and the reason it made sense to me to do it is that the leading NDS being under greater tension are less likely to de-tension and allow the J bend to get as loose. Because they are stretched out more to begin with.

I even just built up this last set to have the lighter ga spokes on the leading drive side as well. Only the pulling drive side trailing spokes are 14/15 ga and the rest are 14/17. And the brass nips on those pulling spokes just for extra measure...


----------



## ericm979 (Jun 26, 2005)

The tension on a spoke will be the same no matter the spoke gauge. 55kgf (or whatever the value) is 55kgf, even if you made a "spoke" out of 1/2" steel rod.

However a thinner spoke stretches more at a given tension than a thicker spoke. If the problem we are trying to solve is spokes becoming completely detensioned due to wheel flex, thinner spokes streteched more at a given tension require more wheel flex to completely detension. 

Since my problem is (or was) NDS spokes breaking at the elbow, I've been building with lighter gauge spokes on the NDS on most of my training wheels.

Unless perhaps you are especially large or are pedalling a loaded tourer up steep climbs you don't need extra thick DS pulling spokes. Many people do fine with 24h CXrays with the NDS laced radial. There's only 6 pulling spokes in this configuration but they handle the load. Humans are just not that strong, and spokes, even thin ones like CXrays or Lasers, are. Also remember that CXrays, Lasers and Race are all the same diameter at the elbow and at the threads, the two places where spokes usually break.

But the thicker spokes on the DS make the wheel a bit stiffer, which is why I use Race on the DS on my training wheels.

If you're interested in theory of wheel construction Jobst Brandt's book is useful. Also Damon Rinard's wheel stiffness tests on Sheldon Browns' site are interesting.


----------



## robt57 (Jul 23, 2011)

I guess I worded it wrong ?

I should have said the lighter spokes are stretched out more to do the same job.


----------



## ibericb (Oct 28, 2014)

Thanks gents. I'll rest easier now knowing that the fundamental physics remain unchanged.

If you're interested in the effects of spoking patterns on rear wheel stiffness (rad as really geeky), this article on the Williams Cycling site provides some great insights.


----------



## mikiek (Aug 18, 2014)

Peter P. said:


> Here's how I do it:
> 
> When a wheel is reaching maximum tension, I will notice the spokes begin to twist and creak as I turn them. I listen, and I FEEL the spokes as I turn them by squeezing the spoke between the fingers of my free hand. When I begin to feel the twisting and just begin to hear the creaking, I back off maybe a quarter turn and seek to increase tension no higher.
> 
> ...


Total newb here, so my question may be misplaced or my assumptions just wrong. It seems like there are 3 potential points of failure in a build - the hub flange spoke hole, the spoke and the rim spoke hole. I guess you could include a nipple in there. I would have assumed the rim is the weakest of the 3. If that is not the case then read no further.

First off, I'm not trying to argue with your method, just to understand. It sounds like the feel you are looking for is when the spoke begins to max out. Isn't it possible that by the time you reach that point, the rim is already beyond tolerances for the spoke hole?

This is where I get confused, the hub, the spoke and the rim all have max tensions (maybe the wrong term but you know what I mean). I'm guessing a hub spoke hole can withstand more tension than a rim spoke hole. From what I have seen, a spoke will max out at way more kgf than you would want to subject a rim to. So do we assume that rim tolerances are what we should use as a spoke tension range?


----------



## ericm979 (Jun 26, 2005)

ibericb said:


> If you're interested in the effects of spoking patterns on rear wheel stiffness (rad as really geeky), this article on the Williams Cycling site provides some great insights.


That's a great article. Thanks for pointing it out.


----------



## ibericb (Oct 28, 2014)

ericm979 said:


> That's a great article. Thanks for pointing it out.


Well, since you seem to be about as nerdy as me (mean that as a compliment), then you might also like this one that deals with stiffness and spoke fatigue. I had never given much thought to the effect of pattern on length, and the impact that has on the different dimensions of stiffness before. It made abundant sense once I rad it, but my head just hadn't gone down that road.


----------



## ibericb (Oct 28, 2014)

Peter P. said:


> The way I determine maximum spoke tension is not through measuring a number but through a "craftsman's feel".
> ...
> Using this method has not let me down in 30+ years.


What you describe is the same approach also described by many others. It seems that approach seeks _maximum tension _that you can reliably and consistently get on the spokes in a wheel. What that doesn't address is that the tension limit in a wheel is not determined by spoke tensile properties, but rather by the rim, and it's compressive limit. 

It seems to me that the utility of measuring spoke tensions is at least three fold: (1) to assure that you have attained a reasonable degree of tension for durability, considering the effect that changes in loading which occur in use (see ericm979's reply yesterday), (2) assuring reasonably balanced spoke tension for long-term stability and durability, and (3) assuring that tension is in the proper range for the rim. It's this latter one that puzzles me a bit. 

I figure that probably the best solution a DIY wheel builder has is to seek a spec from the rim manufacturer either as a published spec or in response to a request. I did that with HED Cycling yesterday (Sunday) and had a definitive answer in less than 6 hours (Belgium C2 rim: 110 front, 125 rear DS) .


----------



## mikiek (Aug 18, 2014)

ibericb said:


> What you describe is the same approach also described by many others. It seems that approach seeks _maximum tension _that you can reliably and consistently get on the spokes in a wheel. What that doesn't address is that the tension limit in a wheel is not determined by spoke tensile properties, but rather by the rim, and it's compressive limit.
> 
> It seems to me that the utility of measuring spoke tensions is at least three fold: (1) to assure that you have attained a reasonable degree of tension for durability, considering the effect that changes in loading which occur in use (see ericm979's reply yesterday), (2) assuring reasonably balanced spoke tension for long-term stability and durability, and (3) assuring that tension is in the proper range for the rim. It's this latter one that puzzles me a bit.
> 
> I figure that probably the best solution a DIY wheel builder has is to seek a spec from the rim manufacturer either as a published spec or in response to a request. I did that with HED Cycling yesterday (Sunday) and had a definitive answer in less than 6 hours (Belgium C2 rim: 110 front, 125 rear DS) .


Your following along the lines of my question. I would think the rim is the limiting factor as the spoke hole is going to tear before the spoke overstretches and breaks.

Curious about your HED contact. Did you just email them?


----------



## ibericb (Oct 28, 2014)

mikiek said:


> Your following along the lines of my question. I would think the rim is the limiting factor as the spoke hole is going to tear before the spoke overstretches and breaks.


According to Brandt if the spoke tension is too great for the rim then with a momentary overload, such as is typically applied in reliving stress, the wheel will warp. He advises using the spoke squeeze method not only to relieve stress, but to also test that the wheel is not over-tensioned.



> Curious about your HED contact. Did you just email them?


Yep - see your PM's.


----------



## BelgianHammer (Apr 10, 2012)

ibericb,

When are you going to quit researching to death this wheel building adventure???!!!!

Dammit, man, be like the intrepid Falcon, Commander Scott, and just go for the Pole already :thumbsup:


Besides, I'm waiting for you to do your's first before I begin my wheel building endeavor, haha..


----------



## ibericb (Oct 28, 2014)

Couldn't make up my mind on rims and hubs until last week. So many good choices, and not enough dollars to do this with reckless abandon. Plus, I have to but _all_ the tools and gadgets - it's a requirement.


----------



## BelgianHammer (Apr 10, 2012)

I hear ya, both about the overwhelming choices and also the tools thing (I am a tool nut, also work and wrench/rebuild BMWs as a side hobby, focus on 1996-2003 5-series, one of the great saloons ever made by a manufacturer, imho.

As far as bike tools, I had bought a Park TS-2 truing stand over a decade ago. But I have only ever transferred rims (taping a rim next the existing one, and transfering the spokes over---which is not building a wheel from scratch in any sense of the word...Only skill I developed was a decent feel and ear for spoke tension). I still haven't ordered that link to that guy's tensionmeter you sent. I want one, and having it along with the Park Tensionmeter, will make me feel all professional when I am looking at them after screwing up my first build-from-scratch wheel


----------



## ibericb (Oct 28, 2014)

BelgianHammer said:


> ...
> I want one, and having it along with the Park Tensionmeter, will make me feel all professional when I am looking at them after screwing up my first build-from-scratch wheel


Roger that!


----------



## Z'mer (Oct 28, 2013)

ibericb said:


> Couldn't make up my mind on rims and hubs until last week. So many good choices, and not enough dollars to do this with reckless abandon. Plus, I have to but _all_ the tools and gadgets - it's a requirement.


Your are on the right path with HED C2s. A pair just arrived here today, from Art's Cyclery. They were on sale for $104. / free ship. 

All the tools - "check". I do mostly fix and repair everything I own. That includes washers, dryers, cars, motorcycles, and the home heating system. Spare igniters and control modules in stock. 

On spoke tension - it may be illuminating to calculate the stress value for a Laser versus Race spoke at 125 kgf. I've done it, actually made a spreadsheet to compare lots of spokes at different tensions. The short story is plastic deformation of the thin spoke section is not that far out of reach for Lasers and heavy riders at 125 kgf. 
And they wonder why they break spokes on bad roads. The point is plastic deformation can stretch the spoke in the thin section, on large force hits under heavy loads. Which makes it lose tension, and then leads to fatigue failure in short order. Do the calcs and tel me what you find, how close is a laser to yield stress at 125 kgf. 
No one really talks about this much, but it's my pet theory.


----------



## ibericb (Oct 28, 2014)

Z'mer said:


> Your are on the right path with HED C2s. A pair just arrived here today, from Art's Cyclery. They were on sale for $104. / free ship.


Thanks for the Art's tip - just saved me ~ $75.



> On spoke tension - it may be illuminating to calculate the stress value for a Laser versus Race spoke at 125 kgf. I've done it, actually made a spreadsheet to compare lots of spokes at different tensions. The short story is plastic deformation of the thin spoke section is not that far out of reach for Lasers and heavy riders at 125 kgf.
> And they wonder why they break spokes on bad roads. The point is plastic deformation can stretch the spoke in the thin section, on large force hits under heavy loads. Which makes it lose tension, and then leads to fatigue failure in short order. Do the calcs and tel me what you find, how close is a laser to yield stress at 125 kgf.
> No one really talks about this much, but it's my pet theory.


Well as I do the calc, the Lasers and thin section spokes (1.5mm) will carry a mid-section stress ~ 1.44X that of the thicker 1.8 mm cross section spokes. If I do the calc for a 250 lb force on a 1.5mm cross section, I come up with ~22.8 kpsi. I don't know the actual yield strength for Lasers, but using 304 SS of ~30,000 psi a 125 kgf prestress should be about 76% of yield strength. Sound about right? If so we would expect about 15.8 kpsi for Race spokes @ 1.8mm cross section.

I'm not sure that the increased yield stress for equivalent loading plays much of a role in spoke failure on thinner cross section spokes. Those thinner sections occur away from the butted ends. If the failures are overload failures in the thin sections, then absolutely the more concentrated stress in thinner is indeed a significant issue. But from what I've heard, most of the failures occur in the thicker sections near the ends, and are fatigue failures not overstress failures. In those cases there has to be a different underlying cause.

I'll throw this idea out - thinner mid-section spokes, with their higher concentrated stress level, move more (strain) under the same load. During stress relieving that increased movement, and sense of higher overall stress, may lead a builder to stop short of applying enough load to the spokes to actually push the stress high enough to yield in those critical spots (e.g., the bend at the hub flange). As a result the spoke may be left with residual stress that hasn't been pushed enough, and leaves it in the elastic deformation zone, but very near the yield strength. A bit of riding later that spoke may be pushed over that limit in that high residual stress zone, which then allows it to loose tension, and more exposed to fatigue.

I may be way off here. It's just a SWAG. If I'm out to lunch (which wouldn't be surprising) I hope one of the smart wheel guys will set me straight.


----------



## jfaas (Jan 31, 2014)

I can't set you straight, but I can tell you this: You can analyze each aspect of your wheel build until you go blue in the face, but you still won't know any better until you start building. Hike up your pants and get in the mud already! Steer clear of the $3/spoke models and if you mess up you won't be dropping a whole paycheck trying to correct the issue.


----------



## Z'mer (Oct 28, 2013)

ibericb said:


> Thanks for the Art's tip - just saved me ~ $75.
> 
> I don't know the actual yield strength for Lasers, but using 304 SS of ~30,000 psi a 125 kgf prestress should be about 76% of yield strength. Sound about right?


Welcome, glad it helped save you $. 
My spreadsheet as a pdf is attached. If there is are errors, let me know. We know cold forging the center reduced diameter section of the spoke greatly increases the strength. But what the new yield is, I don't know, it's obviously above 30-40k psi that you see quoted for 304 stainless. Or my calculations are wrong, as I get almost 100 k psi for a 1.5 mm Laser at 125 kgf. Leading to my conclusion that these may be very close to yielding.


----------



## ibericb (Oct 28, 2014)

Well, dangit, I have no idea how I came up with that 22.8ksi number, because just now when I bang through it I got 100.7 ksi for a 1.5mm spoke at 125kgf load. So, yeah - your numbers are correct and I certainly goofed previously (maybe not enough coffee or this flu thing I'm fighting.

I have no idea what happens to the yield stress in a spoke. I just pulled a standard 304 spec. But as you note, I suspect it changes as a result of alloy specificity and working. I did see a stress-strain graph of a DT Comp spoke (2.0/1.8/2.0) tested by some engineering students, and that had the yield strength at ~150 ksi. I have no idea if that's remotely close, or not.

What we do know is that if the failure is a result of overstressing beyond the yield strength, then we should see overstress failure, with drawing/necking in the failure region. If it was a result of stress against the narrower dimension, then it would be expected in the narrow region midsection, with attendant necking evident around the failure. With a failed spoke in hand it should be fairly straightforward to determine the mode of failure (fatigue vs. overstress), and go from there. I've never seen one of those.

What I do hear is that by far most of the failures occur in the bend near the flange, which should be in thicker butted region. According to Brandt, that is typical of fatigue failure, not overstress failure. But again, that's without anyone reporting the kind of failure, just the location.

From a build standpoint, a complication to the implications of the calculated static stress in use is that the addition of a pressurized tire relives some of that static stress, and possibly by a good amount. So it's still not clear what stress an actual spoke built to the expected stress will endure in use.


----------



## Z'mer (Oct 28, 2013)

Thanks for checking the numbers. 
Yeah, my point is not that spokes fail in the center, we know they fail at the ends.
Usually at the J end, and usually due to back and forth fatigue movement caused by loss of tension. 
Most sources talk about loss of tension being caused by nipples unwinding when the spoke is at the bottom, where it sees the least tension. 

The ultimate yield stress, or where it literally breaks, is far away from from where it starts to see plastic deformation - i.e. where the spoke stretches beyond the linear "spring constant" area, and then does not return to the original shape. So my point is maybe instead of nipples unwinding, loss of tension is caused by spokes stretching (in a permanent plastic way) the middle. 
The result is the same either way - spokes end of breaking way before they should due to fatigue at the end.


----------



## ibericb (Oct 28, 2014)

What you're describing is basically the same thing I threw out this morning as a mechanism for failure, in spite of my screwed up stress number. So on that, we have the same notion in mind. If we're correct on that as the mechanism, then the real issue is insufficient stress relief in the build stage, and that may indeed be a challenge for building with the thinner section spokes.


----------



## jfaas (Jan 31, 2014)

I'll offer my 28 spoke rear wheel built using Sapim Laser spokes as an example. With my rudimentary build techniques and limited tools availability, I finished and have thus far logged about 150 miles on it. Around 25 miles I noticed pinging. I thought I had relieved them well enough, but I guess not. I do not know the exact tension on the spokes. It does seem there is a real limit to the amount of tension the thin gauge can achieve.


----------



## robt57 (Jul 23, 2011)

jfaas said:


> It does seem there is a real limit to the amount of tension the thin gauge can achieve.



But still higher than the spoke bed/hole can endure I would say.


----------



## jfaas (Jan 31, 2014)

robt57 said:


> But still higher than the spoke bed/hole can endure I would say.


I agree with this. If you have ever cut a spoke with a pair of wire cutters, you should have a good understanding of how strong the alloy truly is.


----------



## ericm979 (Jun 26, 2005)

jfaas said:


> I do not know the exact tension on the spokes. It does seem there is a real limit to the amount of tension the thin gauge can achieve.


You probably did not fully stress relieve the wheel, and probably had some spoke windup. And you're likely not at a high enough tension. All common first time builder mistakes (I've done them plenty).


There is a limit to the tension on all spokes. But as correctly observed earlier in this thread, Lasers etc. do not break at the thin section, they break at the elbow which is as thick as other Sapims. The Laser (or CXray) will stretch more at a given tension, but unless you measure that you won't notice it. Other than the spokes winding up there's no difference in building with Race and Lasers.

I suggest a tensiometer and either a spoke holder or flagging the spokes so you can see the windup.


----------



## jfaas (Jan 31, 2014)

I know I had windup and that is why I had the pinging as I didn't use the lateral stress relieving method. This is my first time with the extra thin butted spokes. My tensions were higher than my last build, but my last build was 36 spokes and I think the added spoke count allowed me to get away with the lower tension.


----------



## Mike T. (Feb 3, 2004)

jfaas said:


> I know I had windup and that is why I had the pinging as I didn't use the lateral stress relieving method. This is my first time with the extra thin butted spokes.


You used cutting-edge ultra-thin spokes and didn't perform exemplary bedding/stress-relief/wind-up relief techniques? Those Lasers twist about 1/5th of a turn and you just left it there?  New info on that is on my site.


----------



## jfaas (Jan 31, 2014)

Mike T. said:


> You used cutting-edge ultra-thin spokes and didn't perform exemplary bedding/stress-relief/wind-up relief techniques? Those Lasers twist about 1/5th of a turn and you just left it there?  New info on that is on my site.


Correct, I squeezed the spokes and used the screwdriver handle method, but I did not use the side/lateral relief method. I didn't really understand the final method until after my initial rides.


----------



## Mike T. (Feb 3, 2004)

jfaas said:


> Correct, I squeezed the spokes and used the screwdriver handle method, but I did not use the side/lateral relief method. I didn't really understand the final method until after my initial rides.


What I'm finding, the more that I build with skinny Sapim Laser, is that if I really try hard to remove all the spoke twist every time I move a nipple (the two steps forward, one step back approach), there is no windup (new pics on my site on that). And the same thing happens when I use CX-Ray spokes (that don't twist if held) - when I do Method 5**, on my website, for windup relief, there are no pings, so therefore there was no residual spoke twist.

**Lay wheel on floor, press on rim.

If I build with thicker Sapim Race I'm a bit less careful with windup removal and I do get pings when doing Method 5, which means to me that there is (was) some twist. But either way, no matter, the wheels don't ping when I jet off up the street - it's all been removed by that time.

I think another important step is to increase the j-bend on all the heads-in spokes - either push them down with the thumb (increasing the bend) when lacing them to the rim, or tap them down with the rubber tipped hammer afterwards. This removes the constant strain of that curving bend as the spoke makes its way over the hub flange. I have a new pic on that too on the site.

And also, as I say on my site, referring to "spoke optimization" steps - "I don't care which one is the "best" or what scientific function it provides. I just do them all."

It doesn't take five minutes to do all of them.


----------



## robt57 (Jul 23, 2011)

ibericb said:


> rim manufacturer either as a published spec or in response to a request. I did that with HED Cycling yesterday (Sunday) and had a definitive answer in less than 6 hours (Belgium C2 rim: 110 front, 125 rear DS) .


Interestingly, All this thread reading and the fact that I build 4 sets and replaced 4 rims and built up 2 ENO wheels in the last year... I had a 15% Jenson Coupon and paid $61.00 shipped for the Park Tension meter.

So I ran around checking my craft. My impetus was really the last set with 49 Lasers and 7 Race Sapims. All my wheels where excellent, disc wheels on the money. 

My rear 32 spoke Race with laser NDS had a max tension on the drive side of 126. So I do think I tend to be high strung as I have said before. 

With the exception of the SL23 and a HED Belgium fronts. SL23 28h Lasers, and Belgium 24h Race. The common aspect is these both have low flange hubs interestingly. The SL23 Lasers especially, I must have been too hopped up on caffeine on that one. It would probably been OK, but a little over max for what Pacenti spec is. [conservative?]


----------



## Guest (Mar 28, 2015)

Out of curiosity, do you check final tension with a tire/tube mounted or not? If I wanted to take my finished wheels to the lbs and have them check tensions, should I take bare wheels or wheels and tires?


----------



## ericm979 (Jun 26, 2005)

The tension can change when the tube is inflated. If the tire is mounted then you can just let the air out when checking tension. It only makes a difference when checking absolute tension, not for relative tension among the spokes.


----------

