Why Do Spokes Break?
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- Опубліковано 30 чер 2024
- Unless something getting jammed into it a wheel should not break spokes. It’s the wheelbuilder’s job, that’s us, to use the right components, the right build processes and the right tools to ensure that your new wheels arrive perfectly straight and perfectly tensioned, but importantly that they stay that way without breaking spokes, for their life.
This video takes a look at the main reasons that spokes and nipples break and what we do to pre-empt and mitigate them.
Over the past 16 years of running Wheelworks I’ve seen a lot of broken spokes which has given me a chance to analyse and understand these problems. From day-1 I’ve wanted to build durable, reliable wheels so understanding unexplained failures is critical. It’s incredibly rare that our wheels break spokes but it does happen and we continue to incorporate what we learn into the finer points of our components and processes.
0:00 Introduction
0:47 Breaking at the Head
2:32 Mitigate Head Breakage
3:40 Breaking at the Nipple
4:06 Mitigate Break at Nipple
5:44 Nipples Breaking
6:41 Mitigate Broken Nipple
7:34 Breaking Along the Length
9:24 Question 1
10:09 Question 2
10:27 Question 3
10:58 Question 4
I think there's another reason that spokes commonly break along the length: metal fatigue resulting from torsional stress that comes from unresolved spoke windup during tensioning. This can take months or even years to finally cripple your spokes so you might not ever trace it back to its cause. I think it's probably more common in machine-built wheels than in hand-laced wheels. I had two DT spokes break on my 29er on the same ride. When I got home, I unscrewed an unbroken spoke from its nipple and gently flexed the spoke to clear it from the neighboring spokes so I could measure it. It immediately folded in half and broke. Like the other broken spokes, it looked exactly as if someone had taken a cable cutter and cut through the middle of the spoke.
I now put masking tape flags on my spokes to make sure that the spoke isn't turning with the nipple when the wheel is going through final tensioning. It usually does, even with anti-seize compound on the threads. I glued some shoe leather to the jaws of a pair of small vise grips so I can grab the spoke and prevent that. It doesn't take much of a twist to fatigue the metal. Both the torsional fatigue and the subsequent flexing of the spoke are greatest at the midpoint of length so it's a double whammy of doom. I wish all spokes came with wrench flats like some of the Sapim and Pillar spokes do.
I propably will never order a set of wheels to Europe, but I love the videos, enthusiasm and voice. Keep it up guys!
Thanks Teemu - we're stoked to get positive feedback on these videos ! PS: We do ship to around the world ;-) -Tristan
So much attention to detail and enthusiasm in this video; I learned so much. Thank you!
Glad it was helpful!
tldr for all future watchers, metal (steel) has an elasticity range where even when changing tension from high levels to low levels does not fatigue the metal. When the spokes are exposed to changes in tension outside of elasticity range they fatigue thus connecting to their inevitable demise. To prevent this, you want to either A, not overload your wheel with weight or B, overbuild your wheel to resist even the most extreme conditions in order to maintain that elasticity range of the metal.
Not tldr but 12 minutes of pure gold. It's not just about spoke tension, it's about why spokes break and how best to avoid or remedy it. If you know it all then why bother watching 😁
@@Toob41 we do not know it all. we are trying to get the information, but the talky talky takes too long time
There are several errors in your post. You obviously don't have a Mechanical Engineering degree or background in Strength of Materials because you don't understand the definition of fatigue. Suggest you read a classic text like Shigley's "Mechanical Engineering Design" that covers fatigue. It's in at least its 10th Edition for good reason, so there are plenty of copies around.
Insightful vid, thanks!
Our pleasure thanks James! -Tristan
I'll argue that spokes can break along the length for other factors than something snagged in them too. (I've been doing this over 20 years)
1- Buttts. DT swiss butts are really long and smooth, so the stress applied to them spreads more evenly along the butted area.
Wheelsmith spokes have a really short, sharp and defined butt. They break easy.
2 - Black Coating. The heat treating on new black spokes definitely is a factor in broken spokes. I see a lot of black spokes break without snags. Super stiff unyeilding carbon rims only further propogates this. I still ride stainless spokes. They look better, clean better, and they don't fatigue like black ones do.
Have you seen any high quality black spokes break? I've heard the old wives tale of black spokes breaking but in my experience this is cheap black spokes breaking, not high quality ones. -TT
When i got my first vintage bike i went to my LBS twice a week to change a broken spoke and eventually i ended up dumping the wheel for a more modern wheel and its been a year with no spoke replacements
Wheel guru! Thanks 👍
"A well built wheel should not break spokes", can be interpreted as saying never will break spokes.
Your lifetime warranty can be mistaken to mean your wheel builds will never brake spokes. You must be receiving returns to replace broken spokes.
Overall, your video was very informative.
Hi Noe. Hopefully the video explains that breakages at the spoke's head or thread are entirely dependent on the wheelbuilder - we see very, very few* of these so we're confident saying our wheels will never break spokes in this way. Almost all of the spoke breakages we see are from something being jammed into the wheel - often times it's the customers rear derailleur when the limit-screws aren't adjusted correctly, sometimes it's a stick or rock flicked up while riding - but because we have no control over this we can't promise it will never happen. We can promise that our wheels are incredibly well-built which makes repairing these issues much easier though. Does that make sense? -Tristan
*very, very few: We've had 7 breakages at the spoke head in 16 years. All were with Sapim CX-Ray spokes which is a reason we don't use them any more. We see the occasional broken aluminium nipple which is generally from sealant corrosion.
A wheel that's practically designed for a given application and competently built by an experienced builder will rarely need truing, much less break spokes, IF (the big IF) it's ridden within the parameters for which it was designed.
My wheels rarely require truing. I've built hundreds of wheels in which maybe 3 spokes broke. I design wheels for my customer's application. If I don't approve of the wheel's design, my lifetime truing warranty doesn't apply. No ifs and or buts.
I've broken spokes hitting pot holes. Last night I broke a spoke at the nipple when I took a roundabout very sharply. Both these put sudden and excessive force at one spot. You are on dangerous ground claiming that only bad builds = broken spokes.
I had a large rock kick up and get stuck in the wheel to break my last spoke. Good Times! :) Because of tires clearance, had to do some tuning to make ride home (35km). First good spoke break. My Easton superlight mountain bike wheels break everytime i look at them.
Easton has a long and storied history of making wheels with, umm, less that great spoke life. Do you remember their Velomax brand with the double-threaded spokes? Yikes -Tristan
@@WheelworksHandcraftedWheels My Easton XC-Ones are Double threaded Double butted spokes
@@christeschke9844 Lucky you ;-) -Tristan
I'm riding sometimes hard, bikeparks or some jumps with hard landings, every month i see a slightly loose spokes in the rear wheel
I'm trying to tighten them, just to keep straight tension (if the wheel is +/-1mm (1 milimiter) it's fine for me, right? equal tension is more important than .1 truiness )
I was thinking, if Parktool tensiometer would be useful for me or should I just look if the wheels is fairly straight/round in my frame and spokes not too loose (By sound or by touching them)
Hi friend, what difference can be or what can happen with a wheel that has to 2 spokes replace with a 1 mm of difference of length? By the way is a straight pull spokes wheel, thanks, great channel I can see your high level of knowledge
Great video, very informative.
At my rear wheel, the rim diameter is slightly higher near the weld.
Is it okay to add some more tension to the spokes near the weld in order to pull it back into a nice evenly round circle?
Or is the rim just too bad quality to be even remotely reliable and needs to be replaced?
Great question. You'll need to balance spoke tension with trueness...generally a high quality rim will be able to be true with the spoke tension very even. The spokes should be /holding/ the rim round, not /making/ the rim round. Generally if you need to add a little extra tension at the weld/joint that's ok, but not too much. -Tristan
Great video but curious what spoke tension balance would consider unacceptable. Meaning is a L and R difference of 100% / 45% considered too low? Here the low % is for the drive side of a front disc wheel - as in they’d be at 45% of the tension given to the disc side spokes. Just wondering if this should be say always at least 50% of the high tension side or if this can be managed by building well and stressing the wheel well 🤔
I hope you might have an answer for me since you’re in the industry. I had to incidents where several spokes broke on two bikes while not in use. One bike was never redden and the other was well used in its past but has since not been used. Both had multiple spokes break near the center while being stored in the garage not being used for about 3 years? One is a mountain bike the other a gravel. The mountain bike had no name spokes and the gravel were DT’s. What do you believe may be causing this?
That's almost certainly poor quality spokes. A few years ago there was a massive batch of steel sold to the OEM spoke makers as "stainless" but it turned out it wasn't and many, many, spokes rusted in the middle and broke. I'm guessing you've got something similar going on :-( -Tristan
Hey there! I have a related question…
I’m 6’5” 230. And I ride road only. I have to get my rear wheel trued 1 to 3 times a year.
It’s a 24 spoke wheel. Should heavier riders side 28 spoked-wheels to prevent this result?
Probably would help
@@redmenace5552 I have since had a 56mm wheel built with 28 spokes. I might have 100 miles on them. I am still testing this theory
@THSimagery oh I didn't even notice the comment was from 5 months ago lol. Like the video said tho prob has a good amount to do with the quality of the building itself and the wheels. More spokes can't hurt tho. Best of luck
Regarding broken spoke nipples: seems to correlate with Al nipples on carbon rims. A gradual redox reaction sets in between carbon & Al, slowly corroding and weakening the Al nipple until it cracks and breaks. Typically takes a few years for this to happen. Because of this, with carbon rims, I only use brass nipples.
You're correct that galvanic corrosion happens a lot more with carbon-aluminium than with aluminium-aluminum. An electrolyte is required and either water from riding in the rain, or sealant from damaged rim tape, will really contribute to this process. -Tristan
Yes, seen this as well, had a wheel after some years where the nipples broke away and they look like ist they has dental caries. But I think it depends… My own wheels with the same materials and tubeless sealant and with much more miles of riding show no damage. I guess quality nipples with a good anodisation and also mounting the nipples without damaging the anodisation is key here. I‘ a fan of Sapim polyax nipples in this respect…
@@georglinde3910 There may be ways to mitigate or postpone the redox/corrosion, but using brass nipples avoids the issue entirely, making a lifetime wheel. And brass nipples are more robust especially over time. The cost is about 20 grams per wheel; choose your poison.
Aluminum nipples will always break. Aluminum has a fatigue cycle and once it's reached it will fail. Spokes tighten and loosen continually as the wheel rotates. These are cycles and aluminum only has so many. But they are light and pretty :) Carbon rims are super stiff so they transfer more stress to the nipple.
are electric bikes with rear hub motors more likely to break spokes?
My spokes broke on my gear hub bike along the length after I came off my bike on ice and bije received side impact, my saddle also broke. No derailleur on tree branches involved.
My cargo ebike currently has 3 broken spokes and im waiting on replacements
I am using 16mm nipples on Sapim D lights which is 1.6mm in the middle. Is this a cause for concern in the future? Since I'm thinking the nipples would rub on the spokes because it is slightly bent in the direction of the hub from the spoke hole.
I can also see that I got too long spokes poking out of the nipple by around more than 3mm I think which might make it worse as it is too far inserted and makes the middle thinner part rub more along the long nipples. I also used HM Sapim washers which I think helps with more durability and some directional assistance. Nice video and information. Thanks a lot!
16mm nipples generally bring the thread closer to the hub to allow you to intentionally use spokes which are too short. In your case I suspect your nipple threads have bottomed-out on the spokes. The best thing for you would be to rebuild the wheel with spokes that are 3mm shorter and use 12mm nipples. ~Tristan
Hmm. Very interesting response that is quite different from others opinions. I appreciate your alternative point of view/knowledge. I really hope nothing goes wrong though because I wont be changing anything anytime so soon. Thank You Sir!@@WheelworksHandcraftedWheels
Hey is there a 26" Beach cruiser "Rear rim" and or spokes that can comfortably handle/Support a 350 - 400lbs person's weight without the spokes "Constantly breaking at the REAR J-bend?!!" ALWAYS, ALWAYS, ALWAYS...I'm tried of the S#!t!!🤬 My current bike is the Kent 26" Bayside cruiser Model # 72696 (Black & Blue Discontinued) It's just for general riding around town not racing. Is there a *Rear 26" 7 speed freewheel Rim* suited for *heavy riders* that will fit this model Beach cruiser?! Please help!😥
Faaaaark!
Do you have an ideal spoke tension range on aluminum or carbon rims?
It can depend on the brand / model of rim, however as a rule of thumb we built to 120kgf on the rear driveside and 110kgf on the front disc brake side. -Tristan
What about other materials as with spinergy wheels?
On carbon rims do you use washers under the spoke head ?
None of the carbon rims we use specify a washer. In the early days of carbon rims they were occasionally used to help nipple pull-through as the nipple holes were a weak point but this hasn't been the case for about a decade now. -Tristan
Hey. Just caught on to your You Tube content. Thanks for the great info. I am building up a bike with some DT Swiss 350 hubs and want to do some white spokes as I have a white fork that I want to accent off of. Any recommendations regarding white spokes as my local bike shop he’s not crazy about the idea as they are not anodized, and they are baked on in terms of color. My bike door will mostly be my permanent trainer bike on my turbo trainer. This means I won’t be exposed to the elements and be wearing at the finish.
We have our white spokes powdercoated locally by a really high quality place that does a lot of hotrod car stuff. The quality is really good and we see very little chipping or wearing. -Tristan
I would love it if when I’m ready to build my wheels that I could maybe buy some spokes off you. My local bike shop builds wheels and I’ve had good luck with them but they are not able to get white spokes.
I wish I had professionals like these in Portugal...
I wish we had Portugals weather! :-) -TT
@@WheelworksHandcraftedWheels 😄 Cheers!
When you say thicker spokes break at the head more easily, does that include 'high quality' spokes like the DT Alpine III?
Regards breaking at the nipple end, doesn't lacing pattern effect this as well? If you try and do 4 cross on a 20" BMX wheel you'll have a horrible spoke entry angle!
Most "high quality" spokes won't break at the head, and that includes the Alpine III. You're correct about the lacing pattern with the nipples, although in real life it needs to be pretty extreme (like your bmx example) or a really terrible rim before this makes a difference. 2 cross vs 3 cross on a 29" rim doesn't make much difference for example, but building a rim which has directional spoke holes 'backwards' can cause issues. -TT
@@WheelworksHandcraftedWheels That all makes sense, thanks for the reply. Loving the channel BTW, keep up the good work 👍
@@sandy_knight thanks mate! -Tristan
I bought a new bike, it uses WTB ST i23 TCS 2.0, this wheel, its less than a year old have broken two spokes already, any ideas?
Sorry forgot to say rear wheel drive side, thanks.
Where on the spoke are they breaking? The video should help with what the cause and solution is at the different locations. -Tristan
@@WheelworksHandcraftedWheels hey have had the wheel respoked with stronger spokes. They were breaking at the nipples. So far no problems. Thanks for reply.
@@willmo1725 Unfortunately, as a pro mechanic in a high end shop, I see more quality control issues on WTB wheel products than most any others we sell.
What you've described sounds like a quality control issue. Particularl, WTB tires are problematic, but I see issues in hubs, rims and wheels also. I completely refuse to build wheels with them. They get warrantied and returned more often than all the others by far. I avoid selling WTB products to my customers at the bike shop.
I'm a retired machinist and mechanical inspector from high reliability industries. Highest quality on earth was demanded of me throughout my career. I've also run a small custom wheel building business for 30 years. My wheels rarely require truing and almost never break spokes. Not the greatest for repeat business. Haha!
WTB wasn't always such shoddy quality. I have their '90s New Paradigm greaseguard hubs still in service. They were very expensive back then. They were machined in the USA before they sold out and started manufacturing in Asia. Like so many others in the bike industry.
@@rollinrat4850 thanks for reply. I had ny back wheel relaced at the ike shop heavyer spokes stronger. Also i use water bottles now not plastic. Ottles in a treunk bag. Im still riding the same country gravel road and no spokes lost since.
Congratulation for the explications. Can You Tell me what it s the best grease for the spokes and nipples?
Thanks.
We use a secret grease here in the shop, but any high quality waterproof grease will work really well -Tristan
@@WheelworksHandcraftedWheels Thanks. Best Regards.
These guys are certainly more knowledgeable than me, but still some comments:
- A spoke breaking at the nipple can also occur due nonconcentric spokes/nipples.
- Nipple corrosion on rear wheel, perhaps that's due to environmental effects too (moisture, salt, etc.), in addition to the possibility of galvanic corrosion from sealant (assuming you're talking carbon hoops w/ aluminum nipples?).
After riding in the winter in salted roads, my spoke nipples have started corroding and snapping
Your explanation for breaking at the nipple needs work. Sure if the spoke is too short the first thread is 'exposed'. But if it's too long then the first spoke is up inside the nipple (not exposed at all, unless you count insde the rim and I've never seen the tip of a spoke break off above the nipple where it is exposed).
but either way there is always some variation of overlap of threads, I doubt half the wheels out there have exact thread overlap where every thread is engaged fully.
Furthermore, just because you can't see the threads doesn't mean they are engaged. Nipples have a blank zone of a couple mm before the threads start.
Honestly I think that talking point is moot and it goes back to your previous remark. "Using quality spokes". A cheap spoke is going to be weaker and thus break at a stress point (J bend, head, thread or butt). I've seen a lot of spokes break at all these points, but I swear by DT swiss spokes like you do and I can't say I've seen them fatigue and break at any of these points.
It's this kind of mis-information that gets you tube know it alls in the shop going "I can see one thread that's not right, my wheel is gonna fail I need a refund. Then they ride the wheel for years and have NO issues at all.
Portuguese subtitles please 🙏
I think I need a spokes person😁
I'm available for hire ;-) -Tristan
Rather than an informative video this is just a very long advertisement lmao.
Sorry but the galvanic corrosion on rear wheels from sealant more than front is pure hogwash.
Aluminum has fatigue cycles and once it passes those cycles it will break. Rear wheel aluminum nipples don't break bcause of surface corrosion from more sealant.
They break more because 75% of the riders weight is always on the rear wheel so it takes harder hits during cycles and thus is more prone to fatigue cycles that go over it's limit. A limit which continually lowers throughtout it's life.
Or maybe the guy putting on rim tape at your factory just can't seem to tape the rear wheels as good as the front (Roll eyes emoji)
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these guys don t fuck around ey?