Is Repaired Carbon Fibre Safe? Breaking Point Test
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- Опубліковано 15 бер 2024
- Is it possible to reliably repair broken carbon fibre parts? Conventional wisdom would disagree, but being proudly unconventional, we test repaired carbon fibre parts to destruction. Yes, it was fun.
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Directed and Edited by Girish Appanah - Авто та транспорт
Whenever I hear about carbon fiber safety I think of submarines for some random, undetermined reason. Maybe just me.
I think back to the one that was piloted with a Logitech remote control too.
SNL - "I squish you ... "
@@nunyabusiness7477, can't understand how so many people agreed to get in that thing 🫣
Great tensile strength. Excellent for making containers containing high pressures (trying to stretch the fiber) - Terrible for making containers taking high external pressures (compressing the fiber lengthwise, which very much would like to).
That submarine was holding up against the pressure with resin, carbon fiber in that mix was almost like pushing with a rope.
I then think about diversity hire and that they fired all capable men that were doing a good job working on these submarines and that the fired men already told them it's unsafe but diversity hire knew better. It's almost like real life comedy.
This video should be dedicated to all the Robs out there. The unspoken repairmen who fix all the things we dont know how to or dont have the tools to do so.
he doesn't know how to do it properly either. He makes sail boards not aerospace products... Not saying it didn't work, but its not proper. And hes also not wearing appropriate PPE for someone working with carbon fiber daily.
@@plav032i watched some footage from Pagani factory in TV (multimillion usd cars), no had had masks or gloves when laying down the carbon.
You dont need that but if you work daily with that I would say it would be good to have
i hated the graph at the end with the 50 data points, unlabelled axes, and scaling "data"
Did you just pan past a carbon fiber Honda XR650R without letting us have a better look?
Come on fellas! Let us see that baby! Or better yet, devote an hour of your top-notch videography talking about it and reviewing it and racing it around and ultimately delivering it to me to ride around and then just kind of let me steal it and keep it and ride it forever and ever and ever...
It was BEAUTIFUL
This is the problem when they forget the audience.
As for carbon fibre, I had the miss-fortune of riding a friend bike down a reasonable hill and the rear triangle simple came apart. Not sure what felt worse, me riding a dismantling bike, or knowing the owner saw me "wreck" it without doing anything special. That was decades ago and I still have no idea how I didn't get seriously injured. Or why I might not want any carbon bits besides fairings.
Good eye, didn't even notice it, especially because they all look different by now. Hopefully one finds you someday.
I stumbled into mine looking for a first bike to learn on that wasn't too heavy and wouldn't get destroyed if l dropped it. Had no idea of the lottery l hit until years later, still my only bike and l don't think l could ever replace it
YES THAT
@@microwave221 two BRPs smile at me from my garage daily. Love these bikes!
Came for quality but the last 5 minutes of the video left me devastated Ryan please come back we need you
I love you guys, and I watch all your videos, but the testing had too many variables. The switch from sand weights to metal weights and the failure of the testing rig could have skewed the results.
I think it gets the point across well enough that repairs to CF are worth it over replacing.
@@mbpm6135 really if anything, the missed point was in the fatigue at the end. The plain bar broke earlier because of fatigue. What is that to say that a part isn't nearing the limits of fatigue and now you've sunk money into a repair when it's going to fail again elsewhere? Yes it's good for accidental damage like whacking a tree, but not really if the rest is fatigued and going to fail.
The guy used different style weights, one spread the load out among 1ft of bar length on the repaired bars. The other put all the strain on a 1 inch section of the brand new bar with the metal weights clanking on the CF on every drop. C'mon. Completely different tests doing it like that.
I've come to expect more from this channel, Fortnine is better than this.
Glad I'm not the only one that noticed this.
the plastic weights are also not symmetrical in some drops
@@TheValdesXRyan has a degree in physics, he obviously didn't have much oversight on the testing
Yes, several big problems with the testing here. The rig isn't the same, the weights aren't the same, the rig and weights experience failures, the sample size is 1, and there seems to be a bias towards wanting to show the repair is stronger. If the script for the video is written before filming, it's not really a test any more.
The quick & dirty 3D printed PLA sand-filled weights broke. It’s a UA-cam channel, not a real test lab.
That said, I’ve got a degree in composite manufacturing & repair and I wouldn’t touch those damaged handlebars without a written consent that they couldn’t be used for anything other than non-structural static display or rig testing.
I can repair a CF Boeing better than a United A&P, but I could only ever claim it to be original strength with an engineer’s instructions and write-off.
Anyone claiming that a repair is stronger is either lying or adding mass, which is antithetical to the point of the original CF part, and potentially actually making it weaker. Run.
but still, why didn't the other side break first? The additional bar you bought, was it the same make/model/year as the ones you destroyed before?
Coz otherwise you can't scientifically compare the results
That is a reason I gave a dislike to that video.
By brain went to welding. As you weld one point if done correctly it won't rebreak on the weld but further down the area due to the material being stronger at the weld but weaker around the surrounding area. I think the carbon fiber became stronger at the repair spot but since the area outside the repair spot is a weaker then it decides to break at that point.
he also didn't blend the carbon... he just bonded a dowel inside the bar, and bonded a new section to the dowel. It's only testing the strength of the adhesive he used. A proper repair would taper the existing carbon, and build up carbon layers with alternating weave directions soaked in resin and cured with pressure and heat.
@@TheAtqthe30ththat's not what they are asking. The new bar tested at the end broke at a lower force than the repaired bars. But the repaired bars at a control side that was still original condition, so you should expect that side to still fail at the same force as the new bar. Its a useless comparison and unscientific
@@plav032 Yeah, I kept waiting to see an actual carbon repair. This is just putting a stick in between the break
That felt like a stretch to justify a preconceived point. Rob's repairs we not stronger than the original parts, but they are stronger than some other completely unrelated parts... Ok then.
If the repairs are stronger they would have held up more than the side that wasn't repaired, simple as that.
Seems like it's all subjective, especially considering most carbon parts have a degree of strength variability across the production line anyway.
Rob also just bonded a new section of uni-directional carbon tube to the end, with alot of the force concentrated on the bonding agent. A proper repair should be tapered then filled with layers of cloth with alternating weaves, then resin infused in a vacuum and cured with heat. He did none of that, just literally glued in a dowel and a tube over top.
If repairing a broken bar made it stronger, then breaking it would be standard process in manufacturing. Like come on.
@@148Reaper Stronger, but heavier and more expensive.
The repair simply uses more carbon fiber than the original part had, that is why it is stronger and heavier.
It's like repairing a hole in 1mm sheet of metal with a 2mm sheet of metal.
I worked as the prep and finishing person at one of the longest active carbon fiber bicycle repair shops in the USA (I won't name them). 1. NOTHING short of a frame was every repaired for a customer. We experimented on bars and rims but it was not worth it. 2. we've never had a repaired frame fail at the repair point. They got to the point at the end but this was probably the least informed or informative FortNine video to date.
cutting carbon fibre using an angle grinder without wearing a mask is really not a good idea
Should be a half-mask at the bare minimum. I also use disposable gloves and overalls.
@@plav032 Agreed, carbon fiber (honestly just carbon in general) is nasty stuff to work with, especially to sand or cut with abrasive discs.
Agree re:mask. I’d go facefitted FP3. Everyone’s paranoid about asbestos and then get all blase taking an angle grinder to CF and fiberglass 😬
Come on FortNine! You have been producing quality for so long, that I would hate for this new experiment to start a trend in the wrong direction. I loved the video, with the exception of the conclusion. Look, I get it that your weights broke, you may have changed bar type for the control, your sample number was low, your force measuring methodology is likely very flawed, but your conclusion was the worst part. The conclusion should be that the repair was not stronger than the other side of each handlebar in your test, and that the test rig and methodologies weren't good enough to conclude that the repairs were stronger than the new bar. You aren't known for being misleading, so I hope this sort of video gets more review before being released into the wild. Was Ryan out of town or something??
It's disappointing, and also not the first dodgy test shown on here. Hope they go back to their strengths, discussing riding motorbikes with brilliant videography. They are the best channel on YT at that, I think, but not this stuff.
@thomascook8844 was about to say the same thing and you said it so much better
there was literally another unrepaired side of the bar experiencing in theory the exact same forces when the repaired one broke so there must have been a major difference between the two tests
I agree completely , I must admit that you said it much better than I ever could . Thank you
This is at least the second video where the research and testing was either wrong or seemed misleading to prove a point. I think that we are seeing a shift in the channel now that they have taken off in popularity.
Following this channel for a time now. I am more into the motorbikes, but carbon is everywhere, so still nice to know. However its kinda sad the quality of the testing didn't line up with FortNine usual quality. I mean, if you talk science, then really do it properly, even if you don't like the results. This it what gave this channel its twist. You got too many subs for returning to this "home enthusiast science" level.
Totally safe if done properly.
Not unlike fixing fiberglass.
And he didn't fix it properly.
@@plav032 Thanks, rando voice from the internet. You seem legit. I'll listen to you.
@@WindFireAllThatKindOfThing lmao
Untrue. Especially for structural and technical parts.
Was it made in an autoclave under pressure and temperature ramps?
Doesnit have a crash profile?
Is it designed to fail in a specific way?
For instance a carbin race car tub.
Thats designed to collapse in a crash in a very specific way, any significant structural damage?
Its goes in the bin.
@@deadprivacyis any of what you wrote relevant to bicycle parts?
interesting topic, but I have to agree with the naysayers that the testing would have needed more consistency. In the end I expect your conclusion to be correct, repaired fiber plastic parts are at least safely usable. But the documentation and methodology was lacking and I am left unsure whether the conclusion is actually correct regarding low amplitude fatigue loads as experienced in most applications.
Cycles to failure is a very real concern for all kinds of equipment.
At my old arboriculture gig, we would keep climbing ropes completely separate from rigging ropes, even if they were identical: we wouldn't trust a 6000 lbs test rope to support a man if it had ever been shock-loaded, or if it saw repeated use. Similar considerations were taken for all critical devices.
Well done D.O.D.
Let’s hope you are talking about static ropes (although you shouldn’t really fall on those), otherwise the entire rock climbing community is laughing at you.
@@gherites I think he’s talking about trimming trees.
So if the repairs are more solid than the fresh bar, why did the repaired side breake first before the good part of the handlebar?
@@D3nn1s Maybe all that violence caused a bunch of nano cracks, fissures or whatever?
cycles are a huge deal in aviation, after so many cycles they just scrap the entire airframe.
Been riding with a repaired chainstay for around 2.5 years now! I found a guy that usually does carbon fiber cars and he put a sort of carbon bandaid around 270 degrees of the chainstay. Its held up great since.
The surface of the load was different on repaired handlebars and new one. Repaired had weight distributed on more surface, around 10cm (more less width of grips) the new one had just narrow gym weight installed on like 2cm of the width of handlebar. Thats not apples to apples.
As someone who works with composites for a living there’s a reason why I have an aluminium ebike and not a carbon one(apart from the cost). I’m heavy and when I fails it just fails. As for repairing it, yes you can and you can make it stronger but you can just be moving the problem to around your repair as that will now be weaker than the repair.
It’s just a minefield that can be easily avoided.
Where is this channel going? Serious question
idk I actually skipped thru this vid, mostly because I don't care about this guy or bicycles... the 2nd Fortnine vid I've skipped in years, the first one was another bicycling vid interview style with Ryan and some guy maybe this guy again, I don't remember but don't really care... The other 99% of F9 videos are interesting and masterful though
@@Andrew-mk7rm I agree with you 100 %. I also only skipped the same two videos in the many years that I have followed F9. It’s probably because they are selling Mountain bikes in their stores. They should really have a separate channel for that stuff.
Many bikers ride bikes. 2 wheels good..
I ride bicycles too but I do come here for motorcycle content, I skipped this one too, Im already subscribed to a few bicycle content channels.
I commute to work and do my local errands on my bicycle, it's an aluminum frame with a steel fork, it seems to work fine for me.
@@HaggisPower so do I
The weight of the narrow barbells is located further from the center of the handlebar than on the wide barbells. so, even though the weight is the same - the impact it produces on the handlebar - is completely different
As long as the center of the weight is the same distance from the center of the bar it is not. The sand weight is wider, making it appear closer, but as long as the center of the weights is in the same place it is comparable.
Always gonna be a "nuh-uhh, no it didn't, ya did it wrong" type of whiner....
Yes. Such an obvious flaw. Ryan would not have made such a rookie mistake.
@@dugg117That would only be true if the bar were absolutely rigid and the weight was being applied gradually. Impact loading is a way different animal.
@@thomasstuart2936 it's not breaking where the weight is connected to the bar. Distributed loads can 100% be simplified to their point load equivalent in this case.
This seems to beg the question if Rob repaired a broken new stock bar, would it break at below or above the original strength?
It'd be nice to assume that Rob can repair any carbon fiber handlebar to ~3500Nm break point, but given that his repairs were worse than the originals, it doesn't seem likely. It was nice of Rob to participate in the video but I think it's a stretch to conclude you should repair your new stock handlebar.
Also, the dots are pretty but where are the axis labels?!
I think the test didn't support your premade conclusion so you added some data that would support it. Anyway, the video runs the risk of reducing trust in the brand imo because it's shot in a style that uses the scientific method while simultaneously ignoring it.
@@zachlevyYea I have concerns as well. I've seen others seemingly mimicing Project Farm's style of garage testing, but you have to include all the steps. an
I learned about carbon fibre breaking last year
Making a semi-cameo here is Rob's killer vintage Bronco - that's its fender he's working on in the opening.
The weather at time of filming and the fact that Rob's Bronco doesn't have a top prevented it from having a starring role in the opener!
-D.O.D F9
Due to the nature in which carbon fiber fails I've alway given it a wide berth, its alway catastrophic and almost never ends well. If I need to save a few grams I'll take a poop before the ride, if I need to save a load more, well, I'm 15kg the wrong side of a slice of cake or two, so I thing I'd be better off starting there!! An unplanned emergency dismount at 30kph with my bars in two bits is just not a good vibe!
It's not really rational though. Most of the time, carbon simply _doesn't_ fail - it's an extremely durable material, in particular it has excellent fatigue characteristics (not quite as good as steel, but way better than aluminium). And on a heavy impact, aluminium bars would actually snap just as sudden-catastrophically as carbon bars. The one problem carbon specifically has is that even very small damage (stone impacts) can trigger failure, but that's much more a problem for lower parts of the frame, chainstays and pedals, than handlebars.
If you don't care about weight _at all_ then sure, thick steel is the safest option. But that's not just a couple of grams heavier, more like _twice as heavy_ - anything that's similarly light to carbon bike parts will also be similarly fragile.
@@leftaroundabout What do you know about Ti?
@@garysarratt1Titanium combines to some extend the advantages of steel and aluminium, but it doesn't really change the picture: carbon is still superior in strength/mass. I suppose you could overbuild a titanium frame to be as sturdy as an overbuilt steel frame while not being quite so heavy, but it would still have to be much heavier than a typical carbon frame, and probably more expensive too (titanium is very difficult to work with).
@@leftaroundabout I didn’t know if it can be a direct replacement, mass and size wise, for another metal or carbon. I do notice it seems bulkier, but is the weight & strength good enough for me to opt for Ti next time, or Al or carbon. I’m older than I used to be (what a dumb thing to say🤦🏼♂️), but nearly 35# lighter and better cardio. I can afford any of them, but don’t throw money away if I can help it. Just trying to cut through fawning reviews and ads to buy once, cry once.
@@garysarratt1well, I don't own any titanium bike, so I can't really say how good it is in practice. It is quite possibly the best-compromise material considering strength, durability, compliance and corrosion resistance. No doubt it's a good choice for a gravel/touring bike. But whether it's worth the hefty price tags is questionable.
I think that objectively, titanium only pays off for specialty applications where you need either strength at extreme temperatures or chemical/biocompatibility. Neither is relevant for bicycles.
The graph at 10:30 has me scratching my head. what does the X and Y axis represent here? I feel like this XY plot should have been a bar graph
No longer relevant.
This channel has devolved into clickbait with obviously flawed "tests" to stir up controversy and stimulate engagement in the comments.
It works for F9, but I hate it.
Unsubbed.
@@stevenkelby2169goodbye stevenkelby !!!
@@stevenkelby2169i really don't want this to be true!
@@NickElliottuk Me either but I think it's inevitable in capitalism.
there's also about 50 "data points" from 4-5 drops of a handlebar. it's bogus
The methodology is quite flawed, I'm sorry to say. The idea is great, but the sample size is too small and the difference in weights between the repaired handlebars and store-bought version, means the comparison doesn't really hold up. Same with the breakage of the store bought bars, as it could've broken because the rig failed, instead of visa versa.
The big barbells are too wide, so the weight is distributed along a much larger area. The actual weights concentrate all their mass on a much smaller area, changing the characteristics of the shock load. Ideally, the weight is the width of a hand and is sitting on grips mounted on the bars.
This test doesn't take into account variation in production methods and brands. As 1 of each was tested, you can have a bad apple and it is always going to break. To really have an informed opinion on this, you need to test multiples of each scenario, in a much stronger rig, simulating reality is closely as possible. It also need to take into account fatigue, load at odd angles and more.
Carbon fibre parts are made in many different ways and have varying shapes, each with their own failure points. As the third broken handlebar showed, some breaks cannot be repaired. If handlebars (in essence a carbon fibre tube) can be fixed, it doesn't mean a solid carbon part can be as well. It might, but the results don't apply to all carbon fibre parts.
I understand a test of this size is way beyond a channel like this, financially, but the conclusion from this video is based on a test that doesn't really prove anything. At best the conclusion is that carbon fibre can be repaired in some occasions and can be as strong, if not stronger afterwards. It all depends on the break and the part, and definitely requires an expert.
To add to my doubt, you can´t test that simple how the repair holds up to stress, fatique and strain over time...
Yes. Just go ask Boeing. It’s harder to tell if all the carbon fibre filaments are bonded properly- there doesn’t seem to be much “give” in C-F. Metal flexes and eventually goes ping. C-F holds and then goes “sprang”.
They had some issues with C-F fuselage joints.
Manufacturing defects.
I heard somewhere that particles from repairing (sawing/sanding) carbon fibre were pretty dangerous to the lungs. ? Nice video 👍
Oh shush, now Karen....
@@jamesonpace726 not at all. They arr lethal.
The dust never breaks down and sits in your lungs til you die.
Same condition as silicosis which is why sandlblasting with actual sand is simply never done by anyone with any sense anywhere anymore.
Nor is chopping or sanding fibreglass without respiratory protection, preferably a fed air setup.
Yes its extremely carcinogenic
It is extremely toxic. NADEP experience speaking.
that episode has a good Mythbusters vibe. With less explosion. :D
LOL, I feel they're slowly working up to things that go boom with their awesome videos. I liked the recent truck one, science, sports and fun. Great combo.
But similar destruction! :)
And a similar level of scientific rigour...
I knew there was something missing in this video. Thanks for pointing it out.
I know someone else has said it, but the point still stands:
The repaired end of the bars broke before the unrepaired and undamaged ends. The repair was not stronger than the original.
just seeing a shop with that much carbon dust around makes me uncomfortable... great that there are some individuals out there who are able to save those broken parts from being scrapped :)
Mad respect for the Evil Dead 2 reference.
groovy.
Let’s start a go fund me to bring back Ryan
Every time I see a band shirt during one of these videos, I think: this guy gets me, similar tastes in music and a love for two wheels! Happy belated St. Paddy's day, everyone!
What I find silly is that those parts are essentially injection-molded plastic with carbon reinforcements. They're not "carbon fiber" in the sense that sheets of carbon weave have been laid together like you would find in a high-end bicycle or car frame; they're fiber-reinforced plastic like the more traditional glass-reinforced nylon.
I find that confusing as the term "carbon fiber" gets thrown around a lot but now encompasses multiple manufacturing techniques, which produce wildly different results.
I've had a few carbon wheel rims come into my composite repair workshop. Buggered if I was going to repair them as instantaneous catastrophic failure, followed by a face plant, is a good way to lose friends.
I really loved the evil dead reference 😂😂
A thumbs up just for the Evil Dead/Army of Darkness reference.
He missed an opportunity to say he ran down to the local S-Mart to get that brand new handle bar. :)
I can't believe more people didn't catch this, I was cheering out loud
If the repaired part broke at higher force... why in the first two tests pe handle bar broke ONLY on the repaired side?
Yeah, it doesn't make sense. If the repaired side was stronger as the results are trying to suggest, surely the non repaired side would have broken first in the initial tests.
The random new bar breaking at a lower force is irrelevant. Even the test on the new bar was using different weighting.
What’s the explanation as to why it broke at the point of repair then?
And, tellingly, the other bar broke in a different location. (this is also the spot that Rob refused to fix on the third broken handlebar)
BIG Thumbs up for the Type-O-Negative love. Life time fan of band and NY Hardcore in general.
I understand what you are saying but why did the ones that got repaired before break again and the otherside didn't
I repaired a Downtube headtube junction on a full suspension trail bike. Rode it a few more times and it broke again but on a chainstay pivot, so the whole “if the repair is better than the rest it will break somewhere else” has been true for me.
I was curious for you to break a bar in the test rig then have it repaired and tested again, would be better test I saw
Wouldn't adding that piece on the inside of one side change the balance?
And what was the piece made or? Was it carbon fiber, or metal?
Love the Type O Negative shirt. Interesting video too
Well, you tell the fine repaired part is broken on 3500, but new on 2500. BUT on the repaired part was the second undamaged side that endured 3500.
So, in fact, one bar survived on 3500, another is broken on 2500.
It seems, that all is a crappy lottery.
The repair method was different between the two parts. That's why one is labeled Rob's fancy method and the other Rob's quick and dirty method.
Ive had both. Prefer metal due to bendy bendy than snappy snappy... Also whats the repair cost to new carbon bar ratio?
What is supposed to be on the axis in the plot near the end of the video? I don't get what it's supposed to mean
While the video editing was not as pretty as Ryan, I actually enjoyed this being a cyclist whom also rides a motorcycle. I got my carbon bike frame repaired professionally and always wondered about this. Im also curious about how much weight a carbon repair would add?
If you’re worried about the weight of a carbon fiber repair leave that power bar at home, it’s no good for you anyway.
carbon fiber repairs weigh a negligible amount when done properly. Rob did not do proper repairs, nor does he use proper PPE.
I have so far stuck to steel (e.g. VSFahradmanufaktur) bicycles over Alu and Carbon over this misconception!
No more.
The comments about proper scientific methods have their place here, but may I be one to say thank you for trying to showcase the merits for repair! Carbon fiber is in our lives now and I love that Robert’s Composites is here in our front yard. If you broke something expensive, or it was part of something larger, repair should come to mind. Just because it isn’t perfect doesn’t mean it’s irrational. Customers of Rob will understand!
Rocking the Type O Negative shirt, good one. Great video too!!
Do I trust repaired carbon fiber? I don't even trust NEW carbon fiber! 😳
Steel is real, baby!
Rob repaired a frame for us and it has been perfect ever since. We had him sign it and leave it unpainted just because Rob is awesome.
Thank you for the Evil Dead reference
Wow, there was no standardization in testing methodology between the commercial bar and the repaired ones. Y'all need to remake this with both a larger sample size (I'd personally like at least 3 of each) of each break type and repair job, as well as a consistent and repeatable testing apparatus throughout the entire test. Maybe also throw in a break caused by the test rig rather than artificial means, repairing it, then retesting it. I'm disappointed quite frankly.
Wow! That was so cool, stylish and unique! Loved every aspect of that video! Love motorcycles, mtb and Vancouver, dudes! Thank you for your job.
But help me with understanding, please. How is that happen, that last new bar was dropped from higher, but experienced less N of force? On first bar weights were kind of not centered right. We saw some Truvativ bar in some parts! Show us some proper branded parts maby?
And the most important is - what results would a proper alloy Renthal have?
FortNine in America live from Detroit... Y'all had me with that first part.
This has done nothing to convince me that carbon fiber is safe to repair. Your testing methods are flawed. Aluminum can be damaged and still be safe to use, while CF is a gamble. No thanks! I'm hard on equipment so ill trade a few grams of weight for reliability every day of the week.
Something that i would like to point out is the repeated dropping will cause the break ontop of the larger force exerted each time.
Always pleasing to the ear to hear a Canadian say "beauty" in his native environment.
"Repaired carbon fiber can be as strong or stronger than a brand new product sold for the same purpose." -- While this concluding sentence is correct, I feel like it's shifting the goalposts a little bit. The repair is not as strong or stronger than the original. But it is stronger than another non-repaired but unrelated product.
I agree with this assessment with the exception that your conclusion assumes that test A and test B were of sufficient parity in all variables. The constant failures of the test rig and lack of retests or documentation of potential variance introduced by alterations of the test environment leads me to conclude that a whole host of unmentioned confounding variables were just completely ignored to fit the script's narrative. Product safety testing is not entertainment and no attempt at disclaiming liability can change that. So much of this video isn't just moving the goalposts, but doing so without disclosing how and where they were moved. They presented accelerometer readings with no explanation of how accurate they are, or how they are actually useful as a measurement. The final obvious issue is that when we ignore forces, brands, and materials, we still see that the "new" bar breaks at a logical weak point, the point at a bend and the end of a taper, while the "repaired" bar breaks further down at the repair point. This design was never going to break along the straight and uniform section otherwise. There are only two possible types of conclusions that are even possible at this stage of experimenting: 1, that the repaired parts fail at their cut points instead of the original design's weakest point indicates a weakened repair, or, 2, that these results are inconclusive. To say 3, that the repair was stronger or even acceptable is, well, dishonest, and demonstrates that your claims, methods, stats, proofs of any kind are suspect to manipulation and fraud.
im starting to wonder if there has been a movie reference in every video, and ive just been missing them until recently.
Can we get a link to the sick track that was playing in the middle and then again at the end? Love that funky groove, team F9!
Also, I'm a pool player and I'm sticking with my woody. No carbon fiber shaft for me thanks. 😉
love seeing that Type O shirt!
And the funny thing is, I never got the movie reference until someone else pointed it out and called me an idiot ! Great stuff ! Thanks.
How much to repair and how many carbon fiber repair places are near by?
Music choice is great. Genuinely got emotional during the repair segment.
The biggest problem here? Carbon fiber handlebars almost never break towards the ends. They almost always break near the stem and it's really obvious that they're toast. This video is much more applicable to anything other than handlebars
It doesn't actually make sense to repair handlebars anyway as they're easily replaced, fairly cheap and if anything goes wrong the consequences can be quite nasty.
The reason they did the test with handlebars rather than something more relevant is that they're easily replaced, fairly cheap and shaped in a way that makes testing easy.
Years ago I had a carbon road bike frame fixed by Robert's Composites. I rode and raced it for ages after and was confident it was stronger than new.
I'm watching this days after breaking cheap chinese aluminium handlebar risers that i put on my enduro motorcycle.... yes. from now on i will be careful and learn about what i'm doing. D'oh! thanks for the videos guys, good job!
Love the Evil Dead reference!
So... does this apply to bicycles, motorcycles or both? Cos I clearly remember Ryan telling us that carbon fibre has no fatigue limit and therefore is not an ideal candidate for integral pieces of motorcycle.
Any carbon fibre structural piece of anything really. Driveshaft, connecting rod w/e CF behaves the same in elastic/plastic failure modes.
@FortNine do you mind sharing your 3D Printer Files vor the Test-weights ?
I Love 3d-Printing and want to get "Fit for Riding"
Great t shirt, great band.
Overload failure & crack propogation, as what happened to these bars, are not the same as fatigue. And with the retail bar covered in tape, it was also changed test configuration. Overall your point is true that sometimes carbon fiber parts can be repaired to be as at least as good as original--functionally. But per data, the repair changed the geometry by adding extra material & load distribution on the area of repair, so the strength is going to be different with the same force vs a new tube.
Nice "Army of Darkness" reference. Definitely bonus points for that . . .
well AKSHUALLY that was the sequence from Evil Dead - Dead by Dawn- Ash already has the boomstick come 3
@@kentsokayGood call. I had to get in to the way back machine to remember that one.
You needed to calculate the impact energy, impact force and impact torque. The gym weights would’ve acted like a point load so the torque on the repair would be greater as the second moment of inertia of the bigger masses you started with would’ve been imparting a simple sheer force through the repair and this is the strongest loading mode of a sleeve repair.
You probably need to look at the amount of bar flex that is happening as well and compare the strength of the sleeve with the carbon fibre. Some sort of NDT (ultrasonics or dye pen) to look for signs of fatigue failure (cracking) should’ve been done between tests with this sort of testing method.
If I were to do this, I would get a load cell and a chain block, clamped the bars onto the ground or something heavier than the breaking load, so based on the numbers you have in the chart about 800kg (4000N per side). I would then sling the bars with a load spreader to make it so you have vertical loads at the handle part of the bars. Could probably use grip to stop the slings from slipping … then you just read the load cell display as you wind on more load with the chain block until it fails. This way it’s one load event per test and it’s infinitely repeatable.
Is this now a bicycle channel?
Suprised by the Type O T, fking awesome
Loved the intro
Ok, cool to have someone to fix stuff for you.... but how much does it cost to repair it VS how much to replace it.
3:40 watching the progression of carbon fiber, reminds me of Dave Ronneberg, and building the boot, after growing up with my father, that built a long easy and a cozy MK 4.
N528DR and N785R
I think those are the ones.
He built a couple of “epoxy boxes”, to keep it warm… I still remember the smell
This was a really cool watch!
Keep up the awesome work y'all!
First of all - thank you for the video! Please read this one carefully. The breaking test itself is not good at all. The main difference in these type of composite material is the possible persistence of micro cracks during operation and their accumulation in time. It's really not obvious that if you would test a new element with the same maximum condition you did (without any other breaking tests) - it would always broke, the element could survive extreme condition at first. You did a few tests with lower weights before you use maximum weight. This can be the reason of accumulation of critical persistence of micro cracks that lead to the point where the construction is no longer good enough to resist the force you use. The same thing is with the repair! You can not be sure that your repair is goon enough till you check it at reasonable level. Ride safe! All the best!
Was the third, unbroken bar tested the same brand bar as the repaired bars? If not, that could explain the difference in breaking strength.
Where’s Ryan? This has been a motorcycle review channel for so long.
I, for one, am digging the variety on the channel. And carbon fiber isn't just MTBs! It's good info.
Still, I strongly dislike bicycle content. But this is Fortnine. You learn or you get entertained... in this case both.
Well,
Until Ryan gives me the boot for riding bicycles I'm glad we can oblige on at least a couple fronts.
*I think Ryan is just keeping me around until I let him ride my 990.
-D.O.D F9
Love the windsurfers!
We repair CF stuff in the aircraft industry, but yes, it's an art more than a science, and usually needs a pretty well controlled environment, and a skilled repair person.
Did someone just hacked F9 channel? 🤔
Why are you doing bicycle stuff? Where's the snappy dude who does murder cycle stuff ?
I approve of the Army of Darkness opening montage and of the science o7
Question. What is the practical amount of force that these bars would experience in the real world? I follow lots of Gym guys and they always like over loading deadlift bars to see which is better. Like one bar can hold 4,500lb of force while the other can only hold 4,200lb before bending. Practically no human will ever be able to lift or press that weight. So the test is redundant to real world experience.
So, what is the practical NM force that a rider can exert on these bars?
This is a good question. I recon it would be something like bodymass x speed of impact. But it's not the amount of force on the bars that matter. It's the distribution of load to the center of the bar that matters. You see the center is wider, that's to take the larger force in the middle. But some point has to be the weakest and fail first, without knowing where that is no one can say what a characteristic stress and strain would be for this bar.
Dusting off some physics, for a person of mass m (kg) and bike of fork travel d (mm), landing super nose heavy from a drop of height h (m) on a flat and immovable landing, the average sustained force shared by both ends of the handlebar is F = (m h g)/d, where g is the acceleration due to gravity.
I'm about 90 kg and my bike has a 150 mm travel fork. From a height of 1 meter and landing with all of my weight on my front wheel, I'd exert an average of about 6000 Nm. Each end of the handlebar would support half of that force, which is frighteningly close to where the bars in this video failed. With a 50/50 weight distribution on the bike, I can drop to flat from 2 meters to achieve the same force.
Important caveats: 1) I'm not considering static vs shock loading of the bar. 2) It's hard to get 100% of your weight through the bars on a landing without going over the bars and eating dirt regardless of what happened to your expensive carbon handlebar. The force felt at the bar would be proportional to the fraction of weight supported through the front wheel. 3) I have not included the weight of my bike as part of the supported mass, but I should include some or all of the sprung weight. I just don't know what it is (10 kg, maybe?). 4) As mentioned above, where on the bar that force is applied matters a lot on how that force can be distributed by the bar.
I think I may have convinced myself to not ride using carbon handlebars!
timely video cus I just saw someone advertising carbon repairs
Type o negative shirt. Immediate respect.
That intro summarized my worst nightmare in a few seconds clip.
My Answer Pro-Taper carbon bars and they are indestructible mounted on a MTB. To be honest they are a little scuffed after 15 years with at least 10,000 miles per year on the dirt on rocks. Western Quebec/ Eastern Ontario riding.