Wheelbuilding Question

[Unoveloce]

I have a set of King hubs that I bought used. Since I've had them I've been breakingspokes at the heads. The tension on the wheels is where it should be and even as verified by a tensionometer. The former owner had laced the wheels asymetricaly. Spoke heads did not mirror each other. Of course the spoke holes in the hubs had some marks from where the old spokes had layed. I'm planning on relacing them using spoke head washers. Never having built with them before, I was wondering if anyone out there has used the washers before, if there are any tricks or tips for using them, and if they think the washers will help. Since the wheels keep popping spokes, I'll probably use them anyway since the washers look nice, but it would be great if they were functional as well. If anyone has some pics, that would be great.

[Chad Balthazor]

Brass washers on the spoke heads should help out. Check tolerance with a spoke in the hub before building, and see if you can get a tiny bit of play between the head of the spoke and spoke hole in the hub. If you have some play, a brass washer will definitely help out here. I've used them on multiple rebuilds of worn hubs, including tandem wheels, and have had solid wheels come where without them things may not have been so hot.

[ergott]

There's more to a good wheel build than just tension. You have to stress relieve the spokes as well.

-Eric

[Vancouverdave]

At the heads of the spokes, or at the heads of the nipples? Especially if you're building with aluminum nipples, the threads of the spokes should fill the whole dang thing--the nipple, without reinforcement of the spoke, isn't and shouldn't be a load-bearing part. Broken nipples=too short spokes in al nips.

[Unoveloce]

Thanks for all of the input and feedback. I've been wrenching in the industry for ten plus years and never had this bad of an issue before. I always stress relieve my wheels throughout the process. Interesting about the use of washers on all King hubs. I have multiple sets with no problems so far, although they have always been laced 3x by me. The spokes on this wheel have only broken at the head, despite proper tension and stress relieving, which is why I was going to use the washers. I always measure all the parts of a wheel to come up with spoke length. I've been burned once too many by relying on other people's available data.

[steve garro]

so - i'm confused - is at the head - the "J-bend" or at the nipples? i can't say i've ever heard of washers at the hub shell? at the rim, yes. esp. old POS rims like single wall FIR's and Woblers and such. what are the spokes gonna do, pull through the flange?? even on Phils with big holes i've never seen this prob. what brand spokes? are they DB & breaking @ the butt? do tell...........you have my attention.........Steve.

[Unoveloce]

Sorry for the confusion. My computer is kaput and I'm typing all this from my iPhone. Its a handy little gadget, but not the best when it comes to writing anything longer than a sentence or so The spokes are breaking at the head right after the j-bend. Not the threads. Spokes are plenty long. Actually they are just right as the spoke end lies flush with the nipple slot when tensioned fully.

[steve garro]

Sorry for the confusion. My computer is kaput and I'm typing all this from my iPhone. Its a handy little gadget, but not the best when it comes to writing anything longer than a sentence or so The spokes are breaking at the head right after the j-bend. Not the threads. Spokes are plenty long. Actually they are just right as the spoke end lies flush with the nipple slot when tensioned fully.

what brand, & are they busting at the butt? is this a disc wheel we are talking about as well? any pattern to busting, such as driveside pulling spokes only or disc side only, or is the breakage random? what gauge spokes? sorry for all the questions, but i've been building wheels a long time and you have my interest...........persuit of perfection or something like it, yo. Steve.

[Unoveloce]

Sapim spokes. 14/15 double butted. Alloy nipples. Mavic Reflex ceramic tubular rims. 28 holes. 3 cross. I built the wheels with the pulling spokes heads in. The spokes are breaking on the rear, non drive side between j-bend and the mushroomed part of the head.

[steve garro]

wow, that is far-out. i wish i had an awnser. all i could figure is that the spoke is being forced over a riser created from the previous lacing.........non-drive too, WTF? :frown: Flux: nope. never used those in 24yrs of building wheels.............never saw the need to in 1000's of wheels. never really got into the "super light" realm tho, either............Steve.

[Unoveloce]

Update. It's not just the rear, non-drive side. I forgot about it on the front as well. It's been three on the rear non drive side and two on the front. Another busted spoke on today's ride reminded me that it happens on both wheels. I think it has to be from the previous owners lacing and the indents that it left on the hub. The read was laced asymetrically and the front was pulling spokes heads out. When I relaced the wheels, I did the rear symetrically and both front and rear with pulling spokes heads in. I guess I'll be busy in the shop tonight.

[Sasha]

How do you guys relieve stress, in a wheel, that is? With your hands? Sheldon recommends a crank arm. Brandt seems to suggest you can't really do it with your hands.

[twowheels]

How do you guys relieve stress, in a wheel, that is? With your hands? Sheldon recommends a crank arm. Brandt seems to suggest you can't really do it with your hands.

you can do it just fine with your hands.

[cees]

Unoveloce,

Spokes break for 2 reasons:
1. Play between the hub and the spoke.
2. Insufficient spoke tension.

Good Luck,
Flux

and lots more
like overload
to tiny thickness
too moch tension
not good fitted nipples
corrosion
not good tread
uneven tread lenght
differance in surface tension


and.......
lot of other things

[vredstein]

How do you guys relieve stress, in a wheel, that is? With your hands? Sheldon recommends a crank arm. Brandt seems to suggest you can't really do it with your hands.

Actually, you aren't "stress relieving", you're "stressing" the spokes. You're temporarily increasing tension to insure the spokes heads are firmly seated on the hub's spoke holes, and the nipples are firmly seated on the rim's spoke bed.
It also helps increase the life of the entire spoke by stretching it beyond what will be expected during normal riding. It's kind of like how people will stretch out prior to a work out or running. They'll stretch beyond what a muscle or connecting tissue will experience during the activity.
You can do it with your hands by squeezing same-side parallel spokes together. You can also do it with a soft handled screwdriver or a soft handled pedal wrench. Insert the soft handle between crossing spokes above the last cross and gently twist, so you're exaggerating the cross.

Stress relieving is often associated with the "tink" wound you hear on a lot of machine built wheels when they're first ridden or when you lay it on your lap and press down on either side. It's the sound of twisted spokes untwisting. When you lay the wheel on your lap and press, you're increasing tension on some spokes and reducing tension on others. Those whose tension is reduced will untwist, like a rubber band propeller being released. It's also the sound of a "false" true wheel going out of true, returning to it's "honest" state. If you're good at preventing spoke twist, you probably won't hear this sound.

[Sasha]

Thanks for the instructions about how-to. That makes more sense.

But on this part:

You're temporarily increasing tension to insure the spokes heads are firmly seated on the hub's spoke holes, and the nipples are firmly seated on the rim's spoke bed.

I think Brandt would disagree with you. I'm no expert, just quoting the man.

"Stress relieving to relax these high stress points is accomplished by over-stressing them in order to erase their memory. It is not done to bed the spokes into the hub, as is often stated. Bedding-in occurs sufficiently from tension. However, stretching spoke pairs with a strong grasp at midspan, can momentarily increased tension by 50% to 100%. Because spokes are usually tensioned no higher than 1/3 their yield stress, this operation has no effect on the spoke as a whole, affecting only the small high stress zones where spokes are near yield. By stretching them, these zones relax below yield by as much as the overload."

http://www.sheldonbrown.com/brandt/s...relieving.html

[72gmc]

I think anyone who quotes Jobst Brandt needs to buy the house a beer.

[suspectdevice]

True Story,
Jobst is the "head of engineering" at Cervelo.
I read it on the internet.

[vredstein]

Thanks for the instructions about how-to. That makes more sense.

But on this part:


I think Brandt would disagree with you. I'm no expert, just quoting the man.

"Stress relieving to relax these high stress points is accomplished by over-stressing them in order to erase their memory. It is not done to bed the spokes into the hub, as is often stated. Bedding-in occurs sufficiently from tension. However, stretching spoke pairs with a strong grasp at midspan, can momentarily increased tension by 50% to 100%. Because spokes are usually tensioned no higher than 1/3 their yield stress, this operation has no effect on the spoke as a whole, affecting only the small high stress zones where spokes are near yield. By stretching them, these zones relax below yield by as much as the overload."

http://www.sheldonbrown.com/brandt/s...relieving.html

I suspect it only slightly helps bed them into the hub's flange and agree that proper tension, ie-"natures way" is responsible for this. Before any stressing, I use a punch and a light hammer to tap/bed the spoke heads into the hub's holes.
But Jobst's quote about relaxing high stress points did clarify why this process is called "stressing", but the result is called stress "relieving".

[Sasha]

He's no messiah, but the quote makes sense to me.

But I guess, since 72GMC says, everyone's invited to my house for a beer. I've got homebrewed cider, smoked porter, and maybe something else on tap.