Spoke Gauge Sizing

[Yellow Saddle]

Yes now you have edited your post.

There was a microsecond (OK, millisecond) where I misread your post and replied to what I perceived you said rather than what you said. Your refresh was unfortunate.

 

[Yellow Saddle]

No, it shows the same results, that a 1.8mm straight gauge spoke fails before a 2.0mm swagged (1.8mm in the reduced middle section) spoke.

You are absolutely right, which of course makes a mockery of SAPIM's 48% claims. (For the benefit of the confused: tensile strength is irrelevant no matter which is stronger and which is weaker.)

 

[Venod]

You are absolutely right, which of course makes a mockery of SAPIM's 48% claims. (For the benefit of the confused: tensile strength is irrelevant no matter which is stronger and which is weaker.)

Yes I agree, the 48% looks a bit of a dodgy figure, I would like to know how they have come up with it,

 

[Spoked Wheels]

I will try to answer the best way I can your questions but before I tackle that I'd like to go back to some of your statements. I seem to remember that you already rubbed on the wrong side of @PpPete with your somehow patronising views. I'd like to think that you don't mean to come across that way.

You said
"Spokes purposely made thicker at one end were designed for a market where users misunderstand the mode of failure of spokes rather than educate the users."
"The mode of failure is counter-intuitive. Further, a wheel that has been stress-relieved during the build and has the appropriate number of spokes, has a virtually infinite life as far as the spokes are concerned. Unfortunately none of the bicycle trade schools seem to understand the concept and don't teach it as far as I can see."

Spoke washers are a thing of the past.

With such general comments you imply that you know better and many professional and very experiences wheel builders with a proven record need educating, because either they use triple butted spokes or they still use washers. You also seem to think or at least it's how I understand it that some professional and experienced wheel builders don't get the concept of stress relieving, perhaps you can educate us by explaining how stress relieving is all about and it should be performed.

I can see how less tension will protect the flanges but not how a spoke washer can help. Perhaps you can explain how a washer next to a spoke head protects the flange.

Although, it's only 0.7mm in thickness, it's 0.7mm more metal between the spoke head and the other side of the hole but perhaps more importantly, one needs to observe the marks left on the outside of the hole of a used hub, a washer might help to protect the flange from such damage. I only adopt the methods used by wheel builders that have a long track record of successfully building wheels. If their wheels can perform for 1000s of miles then I want to use some of those techniques too. Wheel building for me is a hobby but that doesn't mean I don't take it seriously, on the contrary, I'm dedicated to learn from all angles I study from books like Jobst Bradt and Roger Musson as they complement very well, RM doesn't go into much depth on the physics of what makes a good wheel but concentrate on the steps to build a good wheel. It's up to me to research and draw conclusions on whether I think a particular technique will improve my wheels and a lot of the times I take note of the results of those techniques being used in the real world.

Stress relieving seats the entire spoke elbow into the hole as well as smear the spoke at the exit point into the flange. A punch will do nothing that's required. The tension on the spoke is borne mostly by the elbow and not the head and I don't see how punching a head against a chamfered spoke hole makes any difference. Perhaps you can illuminate this point?

The punch is used before the stress relieve - at that point the spoke head doesn't look right. the force applied on the spoke's head is 180 degrees different from that of stress relieving. I know how stress relieving sets the elbow but I still like to punch very lightly the head of the spoke. I'm not saying this is a substitute for stress relieving, they are two different things.

Why? are the flanges so thin that they need artificial thickening?

That's my understanding, they are very slightly thinner. I'd love to see that for myself though.

 

[I like Skol]

Anyway, here it goes again. The thread has descended into a 'I know it all and you know Nowt!' slanging match with none of what is being said being asked or relevant to the OP. I think the Q was answered in the first few replies and the OP has now sensibly left the room and gone to the pub for a drink with some friends while the inmates fight it out amongst themselves...... To be honest I think I will look away myself now

 

[Yellow Saddle]

I will try to answer the best way I can your questions but before I tackle that I'd like to go back to some of your statements. I seem to remember that you already rubbed on the wrong side of @PpPete with your somehow patronising views. I'd like to think that you don't mean to come across that way.

I'm not here to annoy or patronize anyone. Follow my argument or don't. I'm here to participate in a debate where we tackle the issues and don't consider contradictory views as an insult. I certainly don't, but I do like to debate from sound principles.

You said
"Spokes purposely made thicker at one end were designed for a market where users misunderstand the mode of failure of spokes rather than educate the users."
"The mode of failure is counter-intuitive. Further, a wheel that has been stress-relieved during the build and has the appropriate number of spokes, has a virtually infinite life as far as the spokes are concerned. Unfortunately none of the bicycle trade schools seem to understand the concept and don't teach it as far as I can see."

Well, don't read malice into my observation but make a counter-argument to it if you disagree. No need to drum up support against an argument by mentioning other disgruntled opponents of my views.

Users do misunderstand the mode of failure. We've seen it here in this very thread. This forum is full of such advice for thicker and stronger spokes. These people will ask for such spokes and insist they know what they want and then hint and tell you that they want it 'cause they want "Strength". There is no use arguing with them, just give them what they want.

As for the second statement, show me a text from a trade school manual that teaches the principles of spoke fatigue and I'll withdraw my statement.

Spoke washers are a thing of the past.

With such general comments you imply that you know better and many professional and very experiences wheel builders with a proven record need educating, because either they use triple butted spokes or they still use washers. You also seem to think or at least it's how I understand it that some professional and experienced wheel builders don't get the concept of stress relieving, perhaps you can educate us by explaining how stress relieving is all about and it should be performed.

Well, make a case for a spoke washer relative to modern aluminium hubs and I'll change my mind on that statement.
Once you have forcefully stress-relieved a spoke, the elbow is no longer perpendicular in the spoke hole but lies diagonally across. A beautiful example is shown in Brandt's book on P80. You say you have the book.

Stress relieving is a process whereby residual stresses inherent in manufactured items are removed in order to prolong the fatigue life of the piece. It is a standard engineering principle applicable to just about any metal manufacturing process as well as other materials including glass, plastic etc. Wikipedia or Google will do much better than me in explaining it in a few paragraphs here but suffice to say that to stress relieved a wire-spoked wheel you have to tension the spokes past yield and then relax them again. We do this, as I'm sure you know, with a lever of sorts wedged between two spokes and then rotated. You can also place the hub on a hard surface, take the wheel like a steering wheel and push down, going round until you've done all the spokes. The technique is up to you.

Although, it's only 0.7mm in thickness, it's 0.7mm more metal between the spoke head and the other side of the hole but perhaps more importantly, one needs to observe the marks left on the outside of the hole of a used hub, a washer might help to protect the flange from such damage. I only adopt the methods used by wheel builders that have a long track record of successfully building wheels. If their wheels can perform for 1000s of miles then I want to use some of those techniques too. Wheel building for me is a hobby but that doesn't mean I don't take it seriously, on the contrary, I'm dedicated to learn from all angles I study from books like Jobst Bradt and Roger Musson as they complement very well, RM doesn't go into much depth on the physics of what makes a good wheel but concentrate on the steps to build a good wheel. It's up to me to research and draw conclusions on whether I think a particular technique will improve my wheels and a lot of the times I take note of the results of those techniques being used in the real world.

I don't quite get where you use the washer but I assume on the elbow side because you are concerned about the dimples in the hub. Firstly, the dimples are not problematic but actually aid the spoke to make a smoother transition around the corner. A spoke pulled tight against a sharp hard corner will fail before one that makes a more curved exit. These dimples are important and most hub manufacturers realize than because they chamfer the hole to make the dimple larger and give spoke contact a bigger area.
Dimples are healthy, even though they confuse us when we have to rebuild a hub that was previously laced in some esoteric way. Read the book you have, it tells you about it in there.

A spoke washer fitted under a spoke head could ostensibly save you from spokes make with a worn die. I've attached a picture of such spokes. If you look at the underside of the head you'll notice die marks from such a worn die. These spokes could cause stress risers in the aluminium hub and propagate cracks. If you have such spokes and can't return them, a washer will help. But then, punching the spoke will simply transfer the mark to the washer and to the hub, recreating the problem from scratch. But, I maintain that spoke washers don't serve any useful purpose anymore now that we have proper thick, soft flanges.

The punch is used before the stress relieve - at that point the spoke head doesn't look right. the force applied on the spoke's head is 180 degrees different from that of stress relieving. I know how stress relieving sets the elbow but I still like to punch very lightly the head of the spoke. I'm not saying this is a substitute for stress relieving, they are two different things.

OK, now you punch very lightly on the spoke. What does that achieve? A light tap with a hammer and punch is simply a ritual with no foundation. What do you mean by "the head doesn't look right" and what do you want it to look like. In other words, what does the little tap achieve?

 

[Tim Hall]

Hear is a paragraph lifted from DCR wheels website. <snip>

This is very vague and possibly suffers from translation. DRC is Italian and their website has always lacked the clarity and benefit of a trained translator.

Some confusion I think. Afnung referred to DCR Wheels, a one man band wheel builder based near Lewes in Sussex As far as I recall, David Hunt, who is DCR wheels is English.

DRC, on the other hand are indeed an Italian rim manufacturer. Whether these facts add to the discussion I don't know.

 

[Spoked Wheels]

OK, let's the discussion end here. I realise that any reply I might come up with will be met by the same patronising and irritating attitude that you have.

Obviously you have your own views and I have mine. I prefer to read / learn / adopt techniques from people that I know for a fact are making wheels for a living, using the same techniques that you criticise . From what I see you seem to criticise just about anybody who has an opinion different to yours. If I remember correctly you said Gerd Schraner ( The Art of Wheelbuilding ) didn't know what he is talking about and gives bad advise, DT Swiss got some of your kind words too, today you had a go at DCR, about something lost in translation, I don't think he is translating from Italian, nor I'm translating from Spanish for that matter. In the past you criticised people for using a tension meter. What's going to be next? Not using a brand of spoke key that you approve So let's just say we are never going to see eye to eye. So please accept that we don't agree on anything and end the discussion.

 

[Smurfy]

Once the spoke is tensioned, then there is no movement of spoke inside the hole. The only time there can be movement is when the spoke is loaded so that tension is reduced to Zero. This is an unlikely and catastrophic event. In service a spoke never goes to Zero.

You're residing in fantasy land if you think spokes never move because they are in tension. Conventional spoked wheels are relatively flexible, and if the spokes are significantly smaller gauge than the flange holes, some of that flexibility will come from spoke movement in the flange hole.

By your definition even a standard 2.3mm hole can therefore also not offer the "snug fit", there being 0.15mm gap all around the spoke if it is centered in the hole.

The spoke would never fit through the flange hole if it were the same size as the hole, as there is an elbow that needs to be manoeuvred through the hole. The 0.15mm is the approximate clearance required to install the spoke. Much more than that would be a sloppy fit

A spoke will always pull against the side of the hole and remain there, no matter how big the gap on the other side is.

You are assuming that the rider is not strong enough, and never brakes hard enough to displace the rim relative to the hub. You need to think about the mechanics of the torques and loads applied.

As I said, the only time a spoke washer can help is if the flange is too thin, leaving too big an exposed elbow bend. However, even that can be corrected by stress relieving or forcefully flattening the elbow against the flange.

If my professional wheelbuilder uses and recommends, that's good enough for me. He's built hundreds if not thousands of wheels, often using unusual components such as electric power assist, so I think he knows what's best.

 

[PpPete]

All down the pub then ?
So long as we don't have to drink Skol

 

[PpPete]

No - somewhat premature. Someone wants to carry on talking technical.
Let's talk about grain size and orientation. Anyone done any photomicrography of different brands of spoke at the elbow - or at the transition between 2.0 mm and 1.8 mm ?

 

[Yellow Saddle]

You're residing in fantasy land if you think spokes never move because they are in tension. Conventional spoked wheels are relatively flexible, and if the spokes are significantly smaller gauge than the flange holes, some of that flexibility will come from spoke movement in the flange hole.

The spoke would never fit through the flange hole if it were the same size as the hole, as there is an elbow that needs to be manoeuvred through the hole. The 0.15mm is the approximate clearance required to install the spoke. Much more than that would be a sloppy fit


You are assuming that the rider is not strong enough, and never brakes hard enough to displace the rim relative to the hub. You need to think about the mechanics of the torques and loads applied.

If my professional wheelbuilder uses and recommends, that's good enough for me. He's built hundreds if not thousands of wheels, often using unusual components such as electric power assist, so I think he knows what's best.

OK, let me ask you this: The wheel is tensioned to 1000N per spoke (a convenient number) and the spoke hole is considerably bigger than the spoke. At what point then do you foresee that the spoke will go into zero tension or even beyond, in order for the spoke to move inside the hole. By moving I mean the spoke side pulled tight against the side of the hole moves away?

Give me some examples under what conditions that could possibly happen.

 

[Yellow Saddle]

No - somewhat premature. Someone wants to carry on talking technical.
Let's talk about grain size and orientation. Anyone done any photomicrography of different brands of spoke at the elbow - or at the transition between 2.0 mm and 1.8 mm ?

Not my work but photographs that used to float around on deja-vu, now Google Groups' Rec.bicycle.tech in the 1990s. This work has been done and is very well understood.

 

[Yellow Saddle]

You're residing in fantasy land if you think spokes never move because they are in tension. Conventional spoked wheels are relatively flexible, and if the spokes are significantly smaller gauge than the flange holes, some of that flexibility will come from spoke movement in the flange hole.


The spoke would never fit through the flange hole if it were the same size as the hole, as there is an elbow that needs to be manoeuvred through the hole. The 0.15mm is the approximate clearance required to install the spoke. Much more than that would be a sloppy fit


You are assuming that the rider is not strong enough, and never brakes hard enough to displace the rim relative to the hub. You need to think about the mechanics of the torques and loads applied.


If my professional wheelbuilder uses and recommends, that's good enough for me. He's built hundreds if not thousands of wheels, often using unusual components such as electric power assist, so I think he knows what's best.

Some confusion I think. Afnung referred to DCR Wheels, a one man band wheel builder based near Lewes in Sussex As far as I recall, David Hunt, who is DCR wheels is English.

DRC, on the other hand are indeed an Italian rim manufacturer. Whether these facts add to the discussion I don't know.

Point taken. But have a look at www.drc.it at some stage to see what I mean. They make some wonderful rims but I've had to struggle with their brochures and website for years and years.

 

[Smurfy]

OK, let me ask you this: The wheel is tensioned to 1000N per spoke (a convenient number) and the spoke hole is considerably bigger than the spoke. At what point then do you foresee that the spoke will go into zero tension or even beyond, in order for the spoke to move inside the hole. By moving I mean the spoke side pulled tight against the side of the hole moves away?

Give me some examples under what conditions that could possibly happen.

I already gave the example when I mentioned torque loading. If the rim rotates slightly relative to the hub, the angle of the spoke must change slightly, and the position of the spoke where it bears against the flange must also change because the forces are no longer balanced. You can try this yourself with a laced wheel in which the spokes are fairly slack. Observing this on a fully tensioned wheel is rather more difficult, because it needs extreme loading such as steep uphills or hard braking. The larger the flange hole is, the greater the movement, so it's best to have the spoke as snug as possible, or use a spoke washer.