Cycling UK Forum

Moved to here from here as the subject drifted from lockrings to truing

How accurately should a wheel be trued? I've replaced a spoke (first time I've tried doing this) and now need to true the wheel. I've brought the spoke up to a reasonable tension and matters have improved but it's still not quite true. As I increase the tension there are some horrible creaking noises emerging from the spoke which makes me a little cautious about what I'm doing so how accurately do I need to true a wheel? Should I expect all sorts of noises like the creaking of a hull as I do this?

Even tension in the spokes is the most important thing. If you have rim brakes The wheel needs to be true enough that it's difficult to see that it's out but if you were to place your finger nail on the frame and wheel rim whilst turning the wheel you might feel it running harder in some places more than others. Don't expect perfection if your not building wheels regularly.

One fault of wheel building is to go for a perfectly true wheel at the expense of an even tension.

So how do you gauge if you have even tension?

jnb wrote:So how do you gauge if you have even tension?

plucking the spokes (like guitar strings) is how I do it, to get a consistent note back. I read Roger Musson's wheelbuilding book, and have done three wheels which all remain true. Well worth the book price, not least because once you understand how a wheel hangs together it makes replacing them on the road simple.

cheers

+1 for Roger Musson. Did you oil the spoke thread and nipple before tightening? Are you checking for twist in the spoke? Either could be causing the creaking.

dont you need to hold the spoke with a pair of pliers to stop it twisting as you tighten the nipple?

No (and I doubt that you could hold it that tight without damaging the spoke). You just stick a piece of tape on the spoke to monitor twist, and relieve it every time you make an adjustment. The oiling helps as well.

With ordinary, round spokes, life is pretty simple. (Aero spokes are different, and awkward)
Tighten a spoke, it creaks. Ignore it.
As you tighten, a round spoke will "wind up" a bit. You can safely ignore that, too. It will unwind with a "ping" when you ride it.
People think that a properly handbuilt wheel shouldn't "ping" when first ridden, although this is not even close to important in the general scheme of what constitutes a properly built wheel. However, a competent builder will do several things which co-incidentally mitigate against lots of pinging from a new wheel. For example, its quicker and more accurate to set all the nipples at exactly the same angle to the rim, so the key goes straight on with no fumbling. Then to tighten half a turn, you go just past a half turn, and back off, which removes wind-up and more importantly keeps the exact orientation of the nipples, so you can accurately add a quarter turn to all the nipples. Its never useful to think about less than a quarter turn. Stressing the wheel several times as it is nearly finished removes almost all the remaining wind-up.
As for pliers and bits of tape, there is simply no need at all. If you are dealing with a corroded old wheel with very stiff nipples, its just a case of getting the "feel" for un-winding the wind-up with the spoke key.

jnb wrote:Moved to here from here as the subject drifted from lockrings to truing

How accurately should a wheel be trued? I've replaced a spoke (first time I've tried doing this) and now need to true the wheel. I've brought the spoke up to a reasonable tension and matters have improved but it's still not quite true. As I increase the tension there are some horrible creaking noises emerging from the spoke which makes me a little cautious about what I'm doing so how accurately do I need to true a wheel? Should I expect all sorts of noises like the creaking of a hull as I do this?

Regarding the creaking: don't worry about it, it doesn't mean that something is about to break. However, lubrication minimizes creaking and reduce friction making it much easier to attain correct tension. So lubricate the spoke thread and the the nipple well on the rim where the nipple head will be seated. You can't lubricate too much; use a heavy oil or grease.

Tighten the nipple so the spoke is slightly flexible (it doesn't rattle, but isn't tight either). Try to press the at spoke elbow with your thumb so the spoke lines up "flat" against the hub flange. This improves the spoke line. Don't sweat it or try to hammer it flat against the flange.

Then grab hold of the new spoke and the nearest parallel spoke and squeeze very hard (use gloves or wrap some clothes around our fingers.)
This is stress relieving, and improves the spoke durability (I will skip the scientific explanation, but it is explained in this thread: http://yarchive.net/bike/stress_relieve.html )

Tighten the spoke further; when you feel resistance, or hear creaking, start tightening by tightening a ½ turn and then immediately turn the spoke key a 1/4 turn the opposite direction; this minimizes spoke wind-up.
The problem with wind-up spokes is, that when the wheel is used the twisted spokes will unwind with a pinging sound, causing uneven spoke tension (very bad) and a wobbly rim. Wind-up isn't so critically when just replacing one spoke though, but avoid it nevertheless. Try to put some tape on the spoke so it makes a little flag. That way you can see if spoke starts to wind up when tightening it.

I think less than 0.5 mm lateral true is the standard tolerance to aim for.

Badly built wheels go out of true when first ridden for a raft of reasons......
a) uneven spoke tension as built
b) failure to stress-relieve
c)failure to perform the final repeating cycle of "stress the wheel, true the wheel, balance the tension.....stress the wheel, true the wheel, balance the tension"......until you achieve a stable wheel with an acceptable balance between trueness and evenness of tension.
d) spokes with a long elbow in a thin hub flange
e) failure to "improve the spoke line" at the flange or rim

With new spokes and nipples, the maximum wind-up you can get is probably less than half a turn. This doesn't alter the spoke length significantly for our purposes, so releasing the wind-up can't alter spoke tension or make the wheel go off true.
I have arthritic hands these days, and for the first wheel I can easily get up to tension without lubrication.....but I can't build all day now. Excess lubrication can spoil rim tapes and tubes. Because their tension is low, non-driveside rear spokes are at risk of un-screwing in use....you can make a case that they should be assembled dry.

I typed a lot of stuff out some time back, its probably still more or less what I think...http://forum.ctc.org.uk/viewtopic.php?f=5&t=49702&hilit=spokes&start=30

531colin wrote:.until you achieve a stable wheel with an acceptable balance between trueness and evenness of tension.

Spot on Colin. If you get PERFECTLY even tension, the rim will be slightly out usually, if you get a perfectly even rim, the tension will be slightly off. My experience.
Do I have a criterion?
Mine is to achieve a perfectly even rim with no more than a semitone, or at the very most, a tone (doh ray) in difference between any two spokes on the same side. This is sufficient and it works.
Spokes overall should be pretty tight.

I've a better method of stress relieving, and I know this as using the hand gripping method I used to still get broken spokes, but with this, I don't.
I put the wheel on the ground and put my heel on each spoke in turn, right around, with a fair bit of weight on it. I never break spokes on such wheels and I'm fairly heavy. Check trueness again after.

THE most important feature of a bicycle wheel is it is true and concentric.

Due to tolerances and inconsistancies in spokes, they will not have 'even tension'.

True a bike wheel so any deviation is not detectable with the eye. Then, no-one will notice.

Ayesha wrote:THE most important feature of a bicycle wheel is it is true and concentric.

Due to tolerances and inconsistancies in spokes, they will not have 'even tension'.

True a bike wheel so any deviation is not detectable with the eye. Then, no-one will notice.

I think this should read "due to inconsistencies in rims, the spokes will not have perfectly even tension." I can't think what properties of the spokes themselves might give rise to uneven tensions.

I generally (used to) get spoke tensions within 5% of target, with occasional outliers at 10% if the rim joint was poor, for example.

Gearoidmuar wrote:...............
I've a better method of stress relieving, and I know this as using the hand gripping method I used to still get broken spokes, but with this, I don't.
I put the wheel on the ground and put my heel on each spoke in turn, right around, with a fair bit of weight on it. I never break spokes on such wheels and I'm fairly heavy. Check trueness again after.

I can see that working for the spokes that lie outside the flange, as you are bending them to lie closer to the flange. However, by the same token you are bending spokes that lie inside the flange away from the flange, and I think that is wrong. Also I wouldn't try it with light, narrow rims, these can be close to pretzeling with just the static spoke tension, without applying extraneous loads that are difficult to control.

In my view, universal adoption of box-section rims and better quality control of stainless steel wire production could have eliminated spoke failure entirely......instead of that we have a few more sprockets, and fewer spoke failures than say forty years ago.....a kind of compromise, I suppose...

the hand squeezing method has one advantage which is that it is almost impossible to overdo it. By the same token it is difficult -with normal strength hands- to actually do it enough. I have had to abandon it as a technique because in order to do it properly, it left me physically exhausted and my hands very sore indeed. No broken spokes when done properly though.

The 'treading' technique works in a similar way except that it also introduces an uncontrolled bending load into the rim. In fact the bending stiffness of the rim works to limit the tension increase in the spokes, and if the rim isn't very strong you will have an ineffective stress-relief procedure and possibly a bent rim to boot.

Colin rightly points out that the above technique (and the hand squeeze come to that) pulls the inside spokes at an odd angle. However this angle is very small, and the primary benefit (yield/work hardening in tension wherever there are significant residual stresses arising from prior yield in bending) is still obtained.

I presently use a tool (that I have designed and built) that more or replicates the effect of the hand squeeze, but with less effort and more consistency. Using it you could easily generate much higher tension increases than other techniques, which potentially might bring another raft of problems along with it. Using this tool I think you could overdo it... but results to date have been encouraging.

cheers

531colin wrote:I can see that working for the spokes that lie outside the flange, as you are bending them to lie closer to the flange. However, by the same token you are bending spokes that lie inside the flange away from the flange, and I think that is wrong.

That sounds logical Colin, except for the fact that it works. They don't break. Walking on the spokes is how the Italians used to stress relieve wheels. Seeing an Italian do this was what first put Jobst Brandt onto stress relieving.
His hand squeezing technique pulls them neither towards nor away from the flange, but it worked for him. He obviously had very strong hands. I don't but I've a might heel!

What's really important is not why it works, but that it does!