migrantwing

I've read the books, I've looked at the websites, I've watched the videos, but what and how?

I understand the need for radial and lateral truing and centering/dishing but the aspect I can't get my head around is spoke tension. Obviously, too low the tension and spokes will be loose and will take away from the true-ness of the wheel, too high and it will put extra stress on the wheel, possibly snapping spokes and cracking the rim/spoke nipples, so, how is the correct or perfect spoke tension found? A spoke tension meter can be used, but where does the balance come between too high and too low, or am I over-analysing things?

TIA

FBinNY 

Assuming you understand how changing the length of spokes by turning the nipples moves the rim, then the question remains about ideal tension.

There's no one answer, but a range based on various conditions. As a starting place, 85-105kgf is a good working range. With heavier rims or thicker spokes the higher end is better, and with thinner spokes or lighter rims, nearer to the lower end is probably better. Once you're within an acceptable working range, more tension isn't better.

That said, there's the issue of dished rear wheels where the rim is offset toward one flange, and away from the other. This requires an imbalance of tension to maintain, (proportional to the difference in offset) and you have to balance keeping the tight spokes from being too tight, while the left aren't too loose. I consider (personal, experienced based opinion) 55-60kgf about the minimum, though I prefer to keep it higher if I can without the right passing 115kgf or so.

So it's a matter of getting the wheel true, keeping the average tension within range, and doing so with a minimum of variation spoke to spoke in tension. This can be tough at first, but with some experience comes together fairly easily unless the rim is badly warped or bent.

However you should expect and allow for tension changes, and possibly the inability to align perfectly at the joint, where rim distortion and stiffness can make it impossible to get it better than a certain point. Most experienced wheelbuilders consider a wheel "perfect" when the joint is aligned as well as possible, and the rest of the wheel is better than that.

migrantwing

Thank you for your knowledgeable reply, FB. Makes things a lot clearer

Retro Grouch 

Ohhhh, I really like that.

leob1

in other words, Voodoo.

davidad

No problem when you shake the right magic rattle at the wheel.

FBinNY 

Nothing at all wrong with Voodoo if you're a skilled practitioner.

leob1

My first problem.

My second problem.
I'll leave the wheel building to those with a bone through the nose.

FBinNY 

We don't do that anymore. It scares off potential clients.

davidad

It sets off my allergies.

rm -rf

Well, FBinNY has covered it.

I'll just mention that thinking of the spoke as a "bolt" and the nipple as a "nut" makes it easier to decide which direction to turn the nipple to tighten the spoke. It was a little confusing at first when I'm looking at it from the hub side.

I still remember the first wheel I built. I was lacing it up, and before the last few spokes were added, and the others were really loose, the whole thing was flopping around and looked like a mess. It's cool when the rim starts settling into place, and the slop is quickly going out of the spokes. A real wheel!

Al1943

Not really. It's the low tension spokes that are more liable to break. This is due to excess flexing causing metal fatigue in the spoke's "J" bend at the hub flange. Excessively high spoke tension may cause small cracks in the rim near the spoke holes or cracks in the hub flange, more common in aluminum hubs. I suspect that damage from low tension is more common than from high tension.

Chesterton

How should one judge proper spoke tension without using a fairly expensive tension gauge? My rear wheel was making a regular creak or thwap sound with every revolution of the wheel. Some reading online led me to suspect loose spokes, and tightening a few of the loosest a quarter turn did make the sound go away. But I don't know if my wheel is properly tensioned to begin with. My roadster has really unusually thick spokes, so they don't even go "ping" when plucked, more like thud.

I'm going to be replacing my tires in the next week or two, and was thinking I would have a go at truing the wheels while I have the tires off. But how do I know if the entire wheel's tension is too low?

cny-bikeman

It's hard for an inexperienced person to judge, and hard to convey over the Internet. The "thud" sound bothers me a bit, though there's less potential for breakage if you actually have thicker than normal spokes (roadster does not really tell us what the spokes are). When you tighten a lubricated nipple it should offer a fairly good amount of resistance to turning, and deflecting the spokes by squeezing together two crossed spokes should be quite difficult. You could check with a good mechanic familiar with wheels or have tension checked with a gauge, although it might be hard to find what is considered proper tension for thicker than normal spokes. Once you know what proper tension feels like you can at least keep it close in the future.

Chesterton

They are 13 gauge spokes, with nipples that don't fit any of the usual spoke wrench sizes (e.g., the Park Tool 3-in-1). Most of the crossed spokes are hard to push apart with thumb and forefinger, but several (including the ones I tightened a quarter turn) are much easier to deflect that way.

FBinNY 

Even tension is easy to manage by sound alone. The individual spokes on either flange will have similar pitch when plucked. But the sound on the right and left flange will be different because the rear rim is dished, or not centered between the flanges. You want the rim centered between the ends of the axle faces, so whatever tension difference achieves that is right.

Now absolute tension is more difficult. There are sites that will give you an audio pitch to match for various spoke lengths and gauges, Otherwise you can find a bike with a similar wheel, (size, no of spokes, cross and gauge) pluck that and compare.

Lastly is to accept that the front is OK, and that the rear should split the difference higher and lower (roughly).

I wish there were an easier way to calibrate fingers over the net, but there isn't. However in the past, most of those who are now experienced builders had our fingers calibrated by having someone more experienced advise. It was an example of the old fashioned method of passing knowledge and skill one person to the next.

GamblerGORD53

For me, too loose is when the spokes easily move without digging into your fingers and they make a crinkle/squak sound.

Too tight is when you are turning the nipples and they make a very high and short plink like the highest notes on a piano. If this is the case, then they are likely almost a full turn too much. I ranked roundness first and even tension at the bottom of the barrel. Using a piece of plastic tape across the fork touching the rim works very well. Rock the wheel back and forth.

I used 3x pricy locking nipples for zero worries about unraveling on my tour bike. I also left my Sturmey rear wheel 2mm off center and used a spacer on the left. 21/24 on the guage, that's not too bad. Not necessarily as good an idea with deraillers.

fietsbob

torque specs are a good how much(?) standard , but those spoke tension gages
are mostly relative to themselves.
Not amongst all kinds and types by precise calibration .

hueyhoolihan

if you use the plucking technique, for want of a better term, that i use, you are right to question proper tension, as it does not really address it. it addresses EQUAL tension well enough, but not absolute tension. for this reason and because i have luxury of multiple wheels at my disposal, some of which have lasted for a decade or so without modification, i compare the plucking pitches of a wheel with the same dimensions and spoke gauge with the one i am tensioning. IME, it has been close enough to work well. multiple successes and more-so the failures, help with the confidence factor here.

cny-bikeman

I always advise new builders to pick the spokes they wish to move and then rotate the wheel so that when they turn them they are looking from the rim toward the hub.

zacster

After thinking I had my new wheels in good shape, I went around and started plucking again after a few rides. Some were already getting loose. So I just threw in the towel and bought a tension gauge. I'll probably use it on these wheels and never use it again, although you never know. Maybe I'll pass it on on eBay.

Myosmith

If I may, I'd like to add a couple questions rather than starting a separate thread:

- I'm building a wheel set with Mavic A719 rims (double walled, double eyeleted, 36H) on Deore LX hubs with DTSwiss butted spokes. I'm getting a variety of opinions on proper spoke tension ranging from 90-110+. I'm using a Park tension gauge and for the spokes I'm using a deflection of 21 = 105 kgF and 22 = 117 kgF. I've got the front wheel built and trued with a variance in tension from just over 21 to 22 even. Is this appropriate tension for this rim, spoke, hub combination?

- One experienced wheel builder told me to build toward the high end of the scale (he's also the one who suggested 110 kgF for the front wheel and drive side rear on this build) as you lose a bit of tension as the wheel "settles in" during the first couple hundred miles of use. He suggested that I build to average 110 and then ride the wheels for a while, then do a final true and tension. Is this appropriate?

- I have also received conflicting opinions on the effect of the number of spokes on appropriate wheel tension. I've heard that the fewer the number of spokes, the higher the tension should be and I know that some low spoke count wheels run very high tensions to remain stiff. I've also been told that when using a quality double wall, double eyelet rim, you can safely run toward the high end of tension with 36 spokes because the force is more evenly distributed along the rim. On the flip side, I was told that more spokes at the same tension increases the total force on the rim but not on the individual eyelettes. How do these factors come into play when determining your ideal tension for a given build?

Mavic wasn't a lot of help. I checked their dealer's site and only found a general reference to building wheels to 85-90 kgF for any of their rims. Since this includes some non-eyeleted, lightweight rims, I'm assuming this is a conservative figure or a minimum. If it matters, I'm a clyde and am running 38 mm tires at about 80-85 psi on these wheels for my gravel grinder.

FBinNY 

You're asking questions that would fill a few chapters in a wheel building book. I'm not going to attempt a comprehensive answer, just give you a quick overlay.

The compression force along the circumference of the rim is a function each spoke's tension times the number of spokes. So mire spokes at the same tension means more compression within the rim. However, this rarely matters because there's plenty of strength in that direction (though it might matter with very light rims).

What matters more is the individual spoke tensions, because excess tension causes excess local stress at the spoke holes, and that's how a rim will fail if tension is too high.

As to why fewer spokes need more tension, that's a bit more complicated. In simple terms, rims deflect against the ground. That deflection slackens the spokes the spoke there, causing it to lose tension. The spoke can only lose tension down to zero, so it's important that the minimum tension stay above that. With longer spans between spokes we can expect greater deflection, so we have to start with higher tension to compensate. The rim's vertical stiffness also plays a part here, so the above is only the short version.

One key thing to keep in mind, is that more tension doesn't make a wheel stiffer, that's a function of the amount of steel used, ie more spokes or thicker spokes. More tension increases the maximum stress that a wheel can take before individual spokes slacken to zero. The right tension isn't the highest, but is related to the spokes and rims used, and the application. I very rarely go for max tension, building rears by focusing on keeping the NDS spokes above a minimum tension f about 55-60kgf, and letting the right be what it is 90-110kgf, sometimes going a bit higher if necessary. (talking 32h wheel). Also, since there's no need to go higher, I usually build fronts at about 75-85kgf.

I hope that covered the key questions, and has you thinking enough to do research it deeper.

One last note, I disagree with the notion that wheel "settle" or loosen slightly in the first month. If they do, it's likely a sign that they weren't properly finished. A proper build finsined with an overload or "stress relief" cycle that stresses components more than they will be in service. This will take out any "settle" that might occur. Also, done right it will remove any wound up spokes, allowing them to unwind and the true checked before the wheel is delivered. Other than possibly a single or spoke or two, and a very minor touch up the builder shouldn't expect to see a new wheel back until a crash.

The only thing I want to see when I deliver finished wheels is a postcard from an exotic destination.

Myosmith

Thanks FB, I can always count on you for good insights.

zacster

While I agree when talking about a wheel-builder wheel that it should be perfect from the start, at least with a self built wheel we have the opportunity to tweak it ourselves. In my case I thought I had it right, but I guess not. With a shop-bought wheel the shop should be willing to tweak it, but I'd then be worried that it wasn't right to begin with. With online bought you're kind of on your own, so it should be perfect.