Originally Posted by
Kontact
You kept breaking elbows, so you concluded that it must be the elbows' fault. Which your confirmation bias was helped by when you found the article we've previously discussed by Wheel Fanatyk that suggested they were great for preventing elbow failures - especially for machine built wheels. But you always like to ignore the machine built part of that article.
Of course I concluded that a broken spoke elbow is the elbow’s fault. Fix the part that is broken not something else that is only marginally related. I started using triple butted spokes long before that article came out by about 14 years. I immediately noticed that the number of spokes I was breaking went from a common occurrence to a rare occurrence. I didn’t change the way I was building and tensioning the wheels. The only thing that changed was the spoke. As I changed the spokes on other bikes I experienced the same result. While correlation doesn’t necessarily mean causation, it doesn’t mean that it
never means causation. Hjertberg’s 2014 article just confirmed what I had already observed for nearly 15 years of use.
The reason I ignore “the machine built part” of
the Crack the Code article that it doesn’t mention machine built wheels. He does say “
Tell other builders, mechanics, and product managers at once,” and he does mention spoke cutting and threading machines but there is zero mention of machine built wheels. Read the damned article!
As a scientist, you went to school so you didn't need to blow up the lab to learn what not to do. And I learned wheel building the correct way with the kind of supervision that helped me learn what not to do without wrecking anything because I stopped and asked when things got off.
No, I didn’t need to blow up the lab to learn what not to do but at some point I had to take the rudimentary instruction and apply it to the real world where I learned far more than what college taught me. I had to develop expertise just like I did with wheel building and bicycle mechanical work.
Who said it is just the amount of aluminum? Did you have scientist hat on?
What else could it be? Ask just about everyone which rim is stronger between a Velocity Dyad and a A23 is and the overall answer will likely be that the Dyad is significantly stronger. But they have similar profiles and dimensions. The Dyad is insignificantly heavier which really makes little difference. And yes, I have my scientist hat on (always). I know that aluminum is a weak metal and it would take a whole lot more of it or a very different configuration to make it stronger.
Rim stiffness is shape and wall thickness. A 385 gram Kinlin is far stiffer vertically than any 480 box section rim. 1970s wheels were flexible rims held in shape with closely spaced spokes, while Roval changed the game by shifting the structural stiffness toward the rim with taller sections - and then eliminating a substantial number of spokes. A 20 spoke MA40 box rim wouldn't last a hundred mile because the unsupported spans would break just like the spans of an unsupported, trussless bridge
Without spokes
no aluminum rim is vertically stiff. They can be easily deformed with relatively minor pressure. That said, I would not have any problem with using a very lightweight rim for myself because the rim really doesn’t matter when it comes to wheel strength. The spokes do all the hard work and get none of the credit.
Vertical stiffness is hardly the problem. If you rode in a straight line all the time, the spokes would probably never have any issues. The real stresses on the rim, spokes, and whole wheel assembly occur in the corners. There you are dealing with bending forces which stresses the spoke at the head in a way that is more fatiguing than vertical forces are.
Chrome causes steel to harden! Don't tell carbon or nitrogen - they'll get jealous.
Chromium changes the way steel hardens, but that is only in the presence of the elements that can actually cause martensite transformations or the like. 18/8 is not hardenable. If spokes were made of heat treatable steel, they would be piano wire and half the diameter.
Carbon hardens iron but chromium hardens and toughens iron even more.
This article from Wisconsin Metal Tech gives values. Yield and tensile strength of carbon steel is 260 MPa and 580 MPa, respectively . Yield and tensile strength of 304 stainless steel is 1560 MPa and 1600 MPa, respectively.
I’m also not talking about heat treating the stainless to harden it. The chromium strengthens it and hardens it over carbon steel. Stainless is less ductile than carbon steel due to the chromium.
Spokes are made of relatively soft and thick steel because that makes them tough, easy to form threads and easy to bend when you are doing things like seating the spoke elbows. Seat the spoke elbows. You have to seat the spoke elbows.
What utter nonsense. Steel that is 1.8mm, 2.0mm, or 2.3mm is not “thick”. The vast majority of spokes used today are stainless. It’s not a soft steel.
Seat the spoke elbows. You have to seat the spoke elbows.
This, like “tensioning the wheel” may be good advice during the build but is not addressing the overall problem. Every wheel I’ve built since I started building wheels have had the elbows seated and been properly tensioned…even up to the point of rim cracking. Prior to using triple butted spokes that didn’t matter. Spokes still broke with regularity under the conditions I put them under until I went to stronger spokes. Yes, stress relieving, spoke seating, and tension are important but they aren’t the end all and be all of wheel building. Materials of construction play a part as well.
"Wheel dynamics" suggests that you think there is something magical going on. But wheels are justs parts assembled together. If some of the parts break because those parts weren't assembled correctly, that doesn't mean all the other parts are tainted. And this is even more the case when the rim is stiff because the load sharing is different than a box section rim where tension shifts and the rim changes shape more easily.
Wheels are most certainly
not “just parts assemble together.” If they were, they would be a whole lot easier to build and maintain. The “wheel dynamics” that you poopoo is all the stuff that needs to be done after the parts are put together. Things like tension, spoke seating, and stress relieving. In other words the “art” part of wheel building. The part, you know, that you harp on about needing instruction for. Wheel dynamics is also about how the wheel interacts with the world while the wheel is being ridden that can throw both that the assembly part and the art part out of kilter.
"Endless spoke failures" are just wheels that haven't had their problem diagnosed and solved. Steel like 18/8 doesn't slowly fatigue like chromoly. If you arrest the problem early, you aren't going to have spokes that survive tensioning but break a month later.
I don’t know where you wrench but I have replaced hundreds to thousands of broken spokes on OEM wheels both new and ancient. I have seen…and had to replace spokes…on wheels that had already had nearly all (or even all) the spokes replaced and yet the continued to break spokes. I know you assume that I am stupid and can’t tell how to repair a wheel but, I assure you, that I’m not a complete dolt. Sometimes it is just better to solve the problem by solving the problem rather than keep putting bandaids on an open artery.
Champion spokes are $.90 x 28 = $25. When I looked up labor in 2025 the range started at $60. So my point was that the minimum cost of building a wheel with new spokes is similar to the minimum cost of a new wheel. And a new wheel can be hand trued for just $20. So why rebuild?
Why rebuild? Because SamSam77 has broken 3 spokes and is having trouble keeping the wheel tensioned. I agree that the wheel has a problem and should probably be replaced under warranty but he is likely to just get another of the same wheel that could develop similar problems. If he has to replace it, why not buy a bit of insurance and replace it with something more durable.
And if rebuilding is so prohibitively expensive, why not take the old mechanic's advice and just try to get the wheel working for $25?
If Sam gets "some help", and the help isn't pro level, he's going to have more problems and think he got bad advice.
Truing the wheel isn’t going to fix the problem. I agree that the wheel has more problems than simple truing will solve. The wheel’s spokes are coming loose which suggest to me that no spoke prep was used on the spokes and the nipples won’t hold tension. A rebuild would solve that problem as well as be an opportunity to get better, stronger spokes. I would not replace the OEM 2.0mm spokes with more 2.0mm straight spokes. That makes no sense. If SamSam77 were going to do that I would agree that he would just get a new wheel (if Jenson won’t replace the wheel under warranty)
But if Sam starts with a wheel with no questionable history and tries to refine it, he'll have the opportunity to learn good technique without second guessing the results.
Or, if he starts with new spokes and a hub and rim that are probably not the issue, he’ll have the same opportunity. The rim is not the problem.
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