Hunt carbon rim exploded while inflating
12-08-23, 08:57 PM
#51
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"This happens a lot, but you'd never know about it, because nobody talks about it. But trust me, it happens. A lot."
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12-08-23, 09:08 PM
#52
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My experience agrees with this with the exception of several 20" (406) aluminum rims on the rear wheel of my folding commuter bike which failed along the center plane. I originally thought these were brake track wear failures which propagated into the rim. Eventually I showed these to Bill Mould, and was told these were more likely caused by high pressure (60psi) in wide (47mm) tires on relatively narrow rims. These were Kinetix rims, and while I can't say the rims were the problem, I did solve the problem by changing to Sun Ringle rims which are slightly wider.
For reference, I weigh about 215 pounds.
Rim failure from hoop stress. Brake tracks were about 1mm thick.
Rear brake was thumping when applied.
Another rim with hoop stress failure.
For reference, I weigh about 215 pounds.
Rim failure from hoop stress. Brake tracks were about 1mm thick.
Rear brake was thumping when applied.
Another rim with hoop stress failure.
12-08-23, 09:19 PM
#53
Senior Member
Does the 100 number on the rim
assume a 25 tire? They should make it obvious
assume a 25 tire? They should make it obvious
12-08-23, 09:22 PM
#54
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There are a lot of CF failures which you will will never hear about, because people who experienced those failures never post it on social media. The failures you hear about on bikeforums and other social media platforms are just a tip of the iceberg a small fraction of a bigger problem that's out there.
If you had data to back up your claim then yes by all means go for it but saying there are unknown unknowns is just silly.
12-08-23, 09:48 PM
#55
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12-08-23, 10:30 PM
#56
Was setting up some Panaracer 38c tires on Hunt Carbon 30 rims and the rim exploded at about 80psi when I was trying to get the bead to set. Reached out to Hunt, noting that the max PSI on the rim was 100, and got this reply.
>>>>.
Curious if the volume not psi argument is legit.
Thanks,
Kent
>>>>.
Curious if the volume not psi argument is legit.
Thanks,
Kent
Force = Area x Pressure
Thank your lucky stars that you didn’t have slightly less pressure and went riding on it, when it would have hit its limit and exploded.
Also, it was good of company to offer you a free replacement.
Your story has given me a reason to reevaluate my potential switch to carbon wheels. Who needs rim that explodes!
12-09-23, 05:03 AM
#57
The first rule of carbon fiber failure is don’t talk about carbon fiber failure. 
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12-09-23, 07:35 AM
#58
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I’m not anti CF, but I do have some personal rules.
-no ultra light CF parts that were designed for 140# racers
-no cheap Chinese CF anything
-name brand, high(er) quality parts
Instead of 1200g wheels, something with a little more beef and margin for error
Instead of ultralight frame sets, I prefer CF cyclocross frames.
Saving grams in the contact points, handlebars, seat post, cranks - nope.
I have zero concerns with CF parts that come from a well known source. I ride Roval C38 wheels - a few extra spokes, a few hundred grams more - still a brilliant ride and plenty fast, and they are rated for gravel/cyclocross duty. More beef, and only marginally slower than ultralight options - marginally.
Other than that my main road machines are high end steel and higher end aluminum. Can they crack as well? Sure. But is it catastrophic type failure? Probably less of a chance.
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12-09-23, 07:35 AM
#59
There are a lot of CF failures which you will will never hear about, because people who experienced those failures never post it on social media. The failures you hear about on bikeforums and other social media platforms are just a tip of the iceberg a small fraction of a bigger problem that's out there.
Back to carbon rims, I've been using them for about a decade both for road and mtb with zero issues. So I'm not that concerned about an internet failure story. Those stories apply to pretty much any product.
12-09-23, 08:08 AM
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12-09-23, 08:10 AM
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If you misuse Anything it will fail. The whole idea that some material is the issue ... if you try hard enough you can mess up steel rims, too. What is a "safe" alternative?
Not abusing your equipment seems to me to be a safe alternative.
People like Lupine Offspring are just clowns ... no more need be said ... but perhaps some folks here are too young or too new to cycling to recall the days Before CF .... or to recall the days when aluminum was a "new" material.
It was widely bruited that aluminum would fail catastrophically because it had zero flex, and the vibrations of riding would cause it ti ... "Assplode!" OMG!!!111!!! Aluminum was the Death Material for bike frames.
Seems that was not quite accurate .....
Then CF forks were introduced ... back over three decades ago ... and there are still people claiming CF forks are made of "Death material" which will "assplode" (Yeah, I am spelling it wrong to make a point) without warning and kill you (My favorite form BF was a guy who crashed into a wall at very high speed while descending a mountain, and whose forks failed later in the ride ... he blamed CF, not crashing at speed head-on into a wall. That is the level of intellect we are contending with (and what did Friedrich Schiller say about ignorance?))
Bikes with CF frames have also been on the market for about 30 years .... but apparently every single incident with CF failure has been fatal, which is why we don't know about them .... and the aliens have abducted everyone who survived .... or the World Shadow Government has banned people whose CF frames have failed from posting on the internet ... they can do that, you know.
Facts (don't so many of us hate facts?) seem to indicate that CF has been used successfully as a material in aerospace, aeronautics, automobiles, bicycles, and many other fields for many decades. Materials science is constantly offering improved materials. And troglodytes are still dreaming of the "Goode Olde Days" when rocks and sticks (and intestinal parasites from raw meat) were the state of the art.
You'd think a simple dictum like "Don't be aggressively stupid" would suffice, but not for some folks .......
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12-09-23, 09:09 AM
#62
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12-09-23, 10:09 AM
#63
Senior Member
I am a mega-Clyde, I am a mega-klutz, and i use CF rims on a bike I use primarily for hauling heavy loads .... and the rims are faultless, pretty much.
If you misuse Anything it will fail. The whole idea that some material is the issue ... if you try hard enough you can mess up steel rims, too. What is a "safe" alternative?
Not abusing your equipment seems to me to be a safe alternative.
People like Lupine Offspring are just clowns ... no more need be said ... but perhaps some folks here are too young or too new to cycling to recall the days Before CF .... or to recall the days when aluminum was a "new" material.
It was widely bruited that aluminum would fail catastrophically because it had zero flex, and the vibrations of riding would cause it ti ... "Assplode!" OMG!!!111!!! Aluminum was the Death Material for bike frames.
Seems that was not quite accurate .....
Then CF forks were introduced ... back over three decades ago ... and there are still people claiming CF forks are made of "Death material" which will "assplode" (Yeah, I am spelling it wrong to make a point) without warning and kill you (My favorite form BF was a guy who crashed into a wall at very high speed while descending a mountain, and whose forks failed later in the ride ... he blamed CF, not crashing at speed head-on into a wall. That is the level of intellect we are contending with (and what did Friedrich Schiller say about ignorance?))
Bikes with CF frames have also been on the market for about 30 years .... but apparently every single incident with CF failure has been fatal, which is why we don't know about them .... and the aliens have abducted everyone who survived .... or the World Shadow Government has banned people whose CF frames have failed from posting on the internet ... they can do that, you know.
Facts (don't so many of us hate facts?) seem to indicate that CF has been used successfully as a material in aerospace, aeronautics, automobiles, bicycles, and many other fields for many decades. Materials science is constantly offering improved materials. And troglodytes are still dreaming of the "Goode Olde Days" when rocks and sticks (and intestinal parasites from raw meat) were the state of the art.
You'd think a simple dictum like "Don't be aggressively stupid" would suffice, but not for some folks .......
If you misuse Anything it will fail. The whole idea that some material is the issue ... if you try hard enough you can mess up steel rims, too. What is a "safe" alternative?
Not abusing your equipment seems to me to be a safe alternative.
People like Lupine Offspring are just clowns ... no more need be said ... but perhaps some folks here are too young or too new to cycling to recall the days Before CF .... or to recall the days when aluminum was a "new" material.
It was widely bruited that aluminum would fail catastrophically because it had zero flex, and the vibrations of riding would cause it ti ... "Assplode!" OMG!!!111!!! Aluminum was the Death Material for bike frames.
Seems that was not quite accurate .....
Then CF forks were introduced ... back over three decades ago ... and there are still people claiming CF forks are made of "Death material" which will "assplode" (Yeah, I am spelling it wrong to make a point) without warning and kill you (My favorite form BF was a guy who crashed into a wall at very high speed while descending a mountain, and whose forks failed later in the ride ... he blamed CF, not crashing at speed head-on into a wall. That is the level of intellect we are contending with (and what did Friedrich Schiller say about ignorance?))
Bikes with CF frames have also been on the market for about 30 years .... but apparently every single incident with CF failure has been fatal, which is why we don't know about them .... and the aliens have abducted everyone who survived .... or the World Shadow Government has banned people whose CF frames have failed from posting on the internet ... they can do that, you know.
Facts (don't so many of us hate facts?) seem to indicate that CF has been used successfully as a material in aerospace, aeronautics, automobiles, bicycles, and many other fields for many decades. Materials science is constantly offering improved materials. And troglodytes are still dreaming of the "Goode Olde Days" when rocks and sticks (and intestinal parasites from raw meat) were the state of the art.
You'd think a simple dictum like "Don't be aggressively stupid" would suffice, but not for some folks .......
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12-09-23, 10:10 AM
#64
I've had several customers who have. It's usually been a dad walking in the store, incredulous that the rim he's holding could have a giant split down the middle or the brake track is doing it's best to go on vacation. Usually combined with a story that his kid got hit by a car or somethin' and is not telling the truth. The other usual crowd, sensibly, is the homeless community that tends to use BMX bike for transportation. So maybe the impression is skewed. Either way, I've lost count.
Thus far I've gathered that for most people Force=pressure x area is just too complicated, and if a thing failed, it's the manufacturers fault for making stupid garbage...Never their own fault for using a thing wrong in the first place.
The customer failures I have seen have pretty consistently been 2" tires at road bike pressures. (100+) 'cause some bmx kid thinks higher pressure=faster or to avoid pinch flats as he makes a landing at the skate park.
This is why cheap stuff is made to be idiot proof.
Thus far I've gathered that for most people Force=pressure x area is just too complicated, and if a thing failed, it's the manufacturers fault for making stupid garbage...Never their own fault for using a thing wrong in the first place.
The customer failures I have seen have pretty consistently been 2" tires at road bike pressures. (100+) 'cause some bmx kid thinks higher pressure=faster or to avoid pinch flats as he makes a landing at the skate park.
This is why cheap stuff is made to be idiot proof.
At least for a generation I have been noticing this pervasive trend of not taking responsibility for one’s own errors - it’s always someone else’s fault. 🤪
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12-09-23, 10:15 AM
#65
Atlas Shrugged:
“For gods sake there are still guys over in Touring sub forum advocating that paper maps are the way to go!”
Under some circumstances, quite useful as a backup plan!
By the way, this Luddite still likes the feel of a book made from paper, turning its pages to read, and placing a book mark before going to sleep!
“For gods sake there are still guys over in Touring sub forum advocating that paper maps are the way to go!”
Under some circumstances, quite useful as a backup plan!
By the way, this Luddite still likes the feel of a book made from paper, turning its pages to read, and placing a book mark before going to sleep!
12-09-23, 10:28 AM
#66
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12-09-23, 10:37 AM
#67
Senior Member
A lot of people are entirely missing the point of the OP’s story. He is not trying to ride around on that 80psi. He is trying to seat the bead. Do you guys understand you have to seat the bead on a tubeless system? If a wheel blows up before the bead can seat, then yes there is definitely a problem with the rim- primarily the dimension of the rim shoulder and the shape of the shoulder and transition area. It is possible that the tire was made too tight as well.
The secondary issue is Hunt’s much vaunted hookless sidewalls. My theory is that the Hunt rim assploded the moment the bead got seated. At that point in time the full 80psi pushes against the weak hookless wall and it gave way.
So either Hunt make their shoulder smaller or smoother for an easier transition, or they make the hookless sidewall stronger to withstand the seating over-pressure. Otherwise I would say this is a fatal flaw. At least for this tire/rim combo.
The secondary issue is Hunt’s much vaunted hookless sidewalls. My theory is that the Hunt rim assploded the moment the bead got seated. At that point in time the full 80psi pushes against the weak hookless wall and it gave way.
So either Hunt make their shoulder smaller or smoother for an easier transition, or they make the hookless sidewall stronger to withstand the seating over-pressure. Otherwise I would say this is a fatal flaw. At least for this tire/rim combo.
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12-09-23, 10:42 AM
#68
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Sad that another well articulated explanation is wasted on the usual suspects. What always baffles me is this same crew of Luddites will pontificate for paragraphs about the amazing ride quality of one steel tubed bike over another even though they are for all intents and purpose identical except for the name on the down tube ends with a different vowel. The amount of threads which have been derailed by this same insanity has effectively ruined these forums, any subject ends with some diatribe about how the way things were done in the 70’s - 80’s was superior. For gods sake there are still guys over in Touring sub forum advocating that paper maps are the way to go!
12-09-23, 10:57 AM
#69
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12-09-23, 11:15 AM
#70
I am a mega-Clyde, I am a mega-klutz, and i use CF rims on a bike I use primarily for hauling heavy loads .... and the rims are faultless, pretty much.
If you misuse Anything it will fail. The whole idea that some material is the issue ... if you try hard enough you can mess up steel rims, too. What is a "safe" alternative?
Not abusing your equipment seems to me to be a safe alternative.
People like Lupine Offspring are just clowns ... no more need be said ... but perhaps some folks here are too young or too new to cycling to recall the days Before CF .... or to recall the days when aluminum was a "new" material.
It was widely bruited that aluminum would fail catastrophically because it had zero flex, and the vibrations of riding would cause it ti ... "Assplode!" OMG!!!111!!! Aluminum was the Death Material for bike frames.
Seems that was not quite accurate .....
Then CF forks were introduced ... back over three decades ago ... and there are still people claiming CF forks are made of "Death material" which will "assplode" (Yeah, I am spelling it wrong to make a point) without warning and kill you (My favorite form BF was a guy who crashed into a wall at very high speed while descending a mountain, and whose forks failed later in the ride ... he blamed CF, not crashing at speed head-on into a wall. That is the level of intellect we are contending with (and what did Friedrich Schiller say about ignorance?))
Bikes with CF frames have also been on the market for about 30 years .... but apparently every single incident with CF failure has been fatal, which is why we don't know about them .... and the aliens have abducted everyone who survived .... or the World Shadow Government has banned people whose CF frames have failed from posting on the internet ... they can do that, you know.
Facts (don't so many of us hate facts?) seem to indicate that CF has been used successfully as a material in aerospace, aeronautics, automobiles, bicycles, and many other fields for many decades. Materials science is constantly offering improved materials. And troglodytes are still dreaming of the "Goode Olde Days" when rocks and sticks (and intestinal parasites from raw meat) were the state of the art.
You'd think a simple dictum like "Don't be aggressively stupid" would suffice, but not for some folks .......
If you misuse Anything it will fail. The whole idea that some material is the issue ... if you try hard enough you can mess up steel rims, too. What is a "safe" alternative?
Not abusing your equipment seems to me to be a safe alternative.
People like Lupine Offspring are just clowns ... no more need be said ... but perhaps some folks here are too young or too new to cycling to recall the days Before CF .... or to recall the days when aluminum was a "new" material.
It was widely bruited that aluminum would fail catastrophically because it had zero flex, and the vibrations of riding would cause it ti ... "Assplode!" OMG!!!111!!! Aluminum was the Death Material for bike frames.
Seems that was not quite accurate .....
Then CF forks were introduced ... back over three decades ago ... and there are still people claiming CF forks are made of "Death material" which will "assplode" (Yeah, I am spelling it wrong to make a point) without warning and kill you (My favorite form BF was a guy who crashed into a wall at very high speed while descending a mountain, and whose forks failed later in the ride ... he blamed CF, not crashing at speed head-on into a wall. That is the level of intellect we are contending with (and what did Friedrich Schiller say about ignorance?))
Bikes with CF frames have also been on the market for about 30 years .... but apparently every single incident with CF failure has been fatal, which is why we don't know about them .... and the aliens have abducted everyone who survived .... or the World Shadow Government has banned people whose CF frames have failed from posting on the internet ... they can do that, you know.
Facts (don't so many of us hate facts?) seem to indicate that CF has been used successfully as a material in aerospace, aeronautics, automobiles, bicycles, and many other fields for many decades. Materials science is constantly offering improved materials. And troglodytes are still dreaming of the "Goode Olde Days" when rocks and sticks (and intestinal parasites from raw meat) were the state of the art.
You'd think a simple dictum like "Don't be aggressively stupid" would suffice, but not for some folks .......
12-09-23, 11:23 AM
#71
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Huh. So, which one caused nearly identical cracks to form at every single spoke hole on my old Fulcrum wheels?
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12-09-23, 12:07 PM
#72
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Reason #3: metal fatigue, which will happen on any Al rim with enough stress cycles.
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12-09-23, 12:25 PM
#73
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At least the OP wasn't just calling out Hunt for a bad wheel when it does appear the OP blew it...literally and figuratively.
Glad that Hunt send the OP a replacement rim...they just could have said 'sucks for you, next time read the owners manual' or some such wording.
Love the stories about 'asplosions'...keep them coming.
Glad that Hunt send the OP a replacement rim...they just could have said 'sucks for you, next time read the owners manual' or some such wording.
Love the stories about 'asplosions'...keep them coming.
12-09-23, 12:33 PM
#74
Then there's metal fatigue as Terrymorse mentioned, which is the usual demise of alloy rims.
Alloy rims are fine. CF rims are fine. It is almost 2024 and CF is now a mainstream material choice for wheel rims and the only choice for high end performance road wheels and most high end mtb wheels too.
12-09-23, 12:38 PM
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Sad that another well articulated explanation is wasted on the usual suspects. What always baffles me is this same crew of Luddites will pontificate for paragraphs about the amazing ride quality of one steel tubed bike over another even though they are for all intents and purpose identical except for the name on the down tube ends with a different vowel. The amount of threads which have been derailed by this same insanity has effectively ruined these forums, any subject ends with some diatribe about how the way things were done in the 70’s - 80’s was superior. For gods sake there are still guys over in Touring sub forum advocating that paper maps are the way to go!
I ride all three types of bikes - carbon, aluminum and steel.
I have aluminum and CF wheels.
I have rim and disc brakes, and I like the discs better.
Assploding CF is the only thing that’s put me in the hospital.
So I’m cautious about what parts and the type of parts I ride, pain will do that to you.
Oh and yes, my high end steel bike is awesome.
