# Has anyone here PERSONALLY crashed because of a broken carbon rim?



## Smiles for miles (Feb 26, 2021)

Greetings all - I'm curious whether the seemingly widespread suspicion of "compromised" carbon rims is legitimate. If a carbon rim gets a ding in it, seems like everyone believes the rim is now likely to fail catastrophically and injure the rider. Question is: is that fear based in actual crashes caused by compromised carbon rims, or is it maybe based on people having less personal knowledge of the material compared to aluminum for example. So has anyone here PERSONALLY crashed from a broken carbon rim? Thanks


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## Suns_PSD (Dec 13, 2013)

No, but I learned this recently: You can beat a CF rim for years with no failures or damage and borrow an Al rim and damage it on your 1st ride, 2nd ride & so on. Al just doesn't hold up even at higher pressures and with an insert.


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## austink26 (Jun 24, 2019)

Been riding carbon rims on my mtb and road bikes for years. Never had any fail. I even recently gifted my used rims to a friend who is heavier and less smooth and they are still running strong. 


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## throet (Oct 8, 2016)

I recently went through the process of replacing a cracked carbon frame, and when I started building up the replacement frame, noticed that both of my DT Swiss XMC 1200 rims had multiple cracks in them, mostly divots from rock strikes. I ended up replacing them as well, but believe that I could have just kept abusing them as I had for the past 4.5 years and may have never noticed. One of the cracks ran all the way through a spoke hole though; so I wouldn't have been able to get that spoke properly tensioned. I'm not at all concerned about catastrophic failure on carbon rims or frames for that matter. Now handlebars, that might be a different story. I still use them though.


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## 127.0.0.1 (Nov 19, 2013)

I have no fear, it's just fact. bikes go fast, you can break bones and die if you come off one unexpectedly.

any compromise noticed anywhere on a part that could get me killed on the bike... I go get it fixed and ride later. wheels are even more special.

imagine an 'oh I can ride on that crack' situation

where you've gone too long, too many rides....many voids have opened up without you being aware....

and one day wham you really get torqued in the chunk and need to muscle your way out of rock...now need ALL that rim integrity to get you out of it....some delam spoke nipples let go and wheel does self destruct. probably an impossible scenario, that could never happen.

but what is known...is weird stuff does happen more often on compromised componentry

that being said carbon failures vary greatly...
I have seen carbon frame with top tube and one seat stay absolutely crushed on a ride, and still be ridable out....hammering, wobbly frame and wheel...but actually intact and motoring hard

Who did a video on a carbon wheel and tried to destroy it and ...it took a lot of doin ?
this almost proves you can take a chunk out of a wheel, maybe stop trying to destroy it, and it'd last thousands of miles


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## Smiles for miles (Feb 26, 2021)

Nice when he takes the tire off and rides the rim. I wonder how an aluminum rim would do with those same tests.


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## rockcrusher (Aug 28, 2003)

Smiles for miles said:


> Greetings all - I'm curious whether the seemingly widespread suspicion of "compromised" carbon rims is legitimate. If a carbon rim gets a ding in it, seems like everyone believes the rim is now likely to fail catastrophically and injure the rider. Question is: is that fear based in actual crashes caused by compromised carbon rims, or is it maybe based on people having less personal knowledge of the material compared to aluminum for example. So has anyone here PERSONALLY crashed from a broken carbon rim? Thanks


I crashed because of a broken Aluminum rim. I can't afford carbon rims. I would buy a carbon rim.


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## AdamfromCanada (Sep 27, 2015)

I broke a rear wheel with a lateral rock strike. I was able to re seat the tire and finish on the wheel. I kind of prefer aluminum but carbon wheels are very tough these days.


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## 834905 (Mar 8, 2018)

I've got a ton of miles on my NOX Farlows and never had a single issue. Had plenty of rim dingers on our rocky terrain here in AZ.

I've smashed in a couple aluminum rims, usually my fault being a bonehead. I trust my carbon rims way more than aluminum at this point.


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## Shark (Feb 4, 2006)

I usually crash because of a tree, rock, root, rut , speed etc.
Never anything carbon related.

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## OnePlus (Feb 16, 2018)

I ride a couple of HTs both with carbon rims (SRAM Rise 60 on one HT and Crankbrothers Cobalt 11 on the other). Been riding them 4 years with almost 14k miles between the two of them. Plenty of dings but never had a failure (knock on wood).


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## edubfromktown (Sep 7, 2010)

All of my crashes have been due to things other than component failure of any sort (carbon or alloy). I built up a set of Light Bicycle carbon wheels back in 2014 and though scratched, scraped and scarred from rock hits they are still going strong with no signs of cracks/fatigue.

I have seen someone destroy a carbon MTB wheel by striking a curb at a bad angle with very low (tubeless) tire pressure. In that scenario, an alloy rim could end up in a less than ideal state with a significant dent but possibly still hold air (or far worse and crack).

I've also been on rides where someone else's carbon frames and seat posts cracked. In both cases it was not a complete failure and they were able to avoid a walk of shame and finish the ride.


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## wschruba (Apr 13, 2012)

127.0.0.1 said:


> I have no fear, it's just fact. bikes go fast, you can break bones and die if you come off one unexpectedly.
> 
> any compromise noticed anywhere on a part that could get me killed on the bike... I go get it fixed and ride later. wheels are even more special.
> 
> ...


This is probably the best response here. Fact of the matter: if a wheel detonates with no prior damage (and we're talking multiple pieces/zero structural integrity), you were not walking away from whatever caused it.

The overwhelming majority of failures start slow, then snowball.


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## kpdemello (May 3, 2010)

Carbon rims from a good manufacturer like Santa Cruz have come a long way. I used to hear about carbon rim failures regularly, but it seems they've mostly figured out how to make them comparable to AL. I have read that many DH/enduro racers don't like carbon rims because they think them more likely to fail. But for most of us, I think a catastrophic rim failure, AL or carbon, is going to be exceedingly rare. It's also going to depend on your circumstances (rocky trails? DH? full suspension or hardtail? race vs recreation? etc). 

Bottom line is that everything breaks, and different materials break in different circumstances. The real question is whether you think the benefits of carbon outweigh the detriments. For me, the price difference isn't worth any added benefit. But other people think differently.


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## B. Rock (Mar 9, 2011)

I had one catastrophically fail in a rock garden at speed and blow the tire instantly but it didn't take me down. Earlier in my riding career it might have, but I've taken enough spills to be able to recover pretty well. It now hangs on the wall of shame.


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## TylerVernon (Nov 10, 2019)

I only ride chiner carbon. Snapped a rear one in a rock garden but to be fair, it was a superlight xc rim on a 2.25 tire and I barreled in there with not enough pressure in my tires haha. The tire wouldn't hold air but the rim was still good enough to do the ride of shame back home on a flat tire and snapped rim.


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## DrDon (Sep 25, 2004)

I’ve ridden a carbon rim for 2 or 3 weeks with a crack in it. Also a carbon wheel won’t deform if you snap a spoke or two. I personally don’t know of any catastrophic failures. 

I think the technology has improved and the weights have gone up. My current bike and wheelset is heavier than I used to run. 

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## Jayem (Jul 16, 2005)

So I've had two CF rim fractures between 6 CF wheelsets, 4 bikes and somewhere around 8 years. Given how I used to trash rims on big hits, this is exceptionally good for me. The two fractures were caused by running pressure too low. One, I distinctly remember that I wanted or should have adjusted pressure prior to the ride and I didn't. Had the "gunshot" go off on a rock culvert. Thought I bottomed my shock, but everything seemed ok, kept going, noticed some sealant coming out and tire going low eventually. Put a tube in and rode 7 miles of hard DH to the car. The 2nd one, similar story, sometime in the days before noticing I had a hard bottom out on a rock and right before an enduro race after running a jump-line for practice I noticed the crack. Furiously sped home and got my replacement rim and was able to do the race. In both cases, despite what looked like serious structural issues, the wheel had held up just fine. One of our local one-man-shop operations said he had someone that ran the entire season a couple years ago with a cracked rim. I wouldn't tempt fate like that, but one thing that stands out to me is that these things are strong as hell. They can take huge sideloads and hard hits and keep running. You run too low pressure and yes, you risk cracking the rim, but as long as you run enough pressure, they are strong as nails. My first CF wheelset is still going strong, having been originally built as an enduro wheelset, then re-laced 3 times and eventually relegated to my training XC wheelset. I've gotten so much life out of those that if they broke, I wouldn't be sad or mad.


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## Davide (Jan 29, 2004)

Smiles for miles said:


> Greetings all - I'm curious whether the seemingly widespread suspicion of "compromised" carbon rims is legitimate. If a carbon rim gets a ding in it, seems like everyone believes the rim is now likely to fail catastrophically and injure the rider. Question is: is that fear based in actual crashes caused by compromised carbon rims, or is it maybe based on people having less personal knowledge of the material compared to aluminum for example. So has anyone here PERSONALLY crashed from a broken carbon rim? Thanks


You know, I have a crazy light carbon wheelset (Light Bicycles, 1170 grams before valves) that I originally used on my cross-country bike, but eventually became my second wheelset for my Ibis HD3. I am only 70 Kg, jump well below 3 feet, but I do ride quite aggressively ... and they are still going strong. I suspect my DT XMC 1200 at 1440 grams will outlive me.


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## Arm&Hammer (Dec 19, 2020)

Had a carbon wheel explode on me doing 60mph on my road bike years ago. It was 90 degrees and I was descending a mountain pass. Was on my new bikes first ride, ended up crashing into the shoulder and was not injured but scared! It was the rear wheel and it delaminated then broke into several pieces then the rear drop outs hit the ground and smashed the rear of the frame and tore off the derailleur. The bike was 10 grand and I was not happy, the wheel company said I abused the wheel and the bike company refused any assistance. Hired an attorney and the bike company sent me a new bike! I sold the wheels on it first thing!


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## Smiles for miles (Feb 26, 2021)

Arm&Hammer said:


> Had a carbon wheel explode on me doing 60mph on my road bike years ago. It was 90 degrees and I was descending a mountain pass. Was on my new bikes first ride, ended up crashing into the shoulder and was not injured but scared! It was the rear wheel and it delaminated then broke into several pieces then the rear drop outs hit the ground and smashed the rear of the frame and tore off the derailleur. The bike was 10 grand and I was not happy, the wheel company said I abused the wheel and the bike company refused any assistance. Hired an attorney and the bike company sent me a new bike! I sold the wheels on it first thing!


Rim brake rims right? I've heard that heat buildup on those is bad.


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## Arm&Hammer (Dec 19, 2020)

Smiles for miles said:


> Rim brake rims right? I've heard that heat buildup on those is bad.


Yep, but still stays in the back on my mind. Had another rider had an ENVE completely crush on a dip on single track. Wheel was in many pieces, rear wheel and they were not hurt but had a long walk out.


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## sergio_pt (Jan 29, 2007)

Arm&Hammer said:


> Had a carbon wheel explode on me doing 60mph on my road bike years ago. It was 90 degrees and I was descending a mountain pass. Was on my new bikes first ride, ended up crashing into the shoulder and was not injured but scared! It was the rear wheel and it delaminated then broke into several pieces then the rear drop outs hit the ground and smashed the rear of the frame and tore off the derailleur. The bike was 10 grand and I was not happy, the wheel company said I abused the wheel and the bike company refused any assistance. Hired an attorney and the bike company sent me a new bike! I sold the wheels on it first thing!


What rim was it?


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## Arm&Hammer (Dec 19, 2020)

sergio_pt said:


> What rim was it?


Was a Reynolds


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## slcpunk (Feb 4, 2004)

I don't see the relevance, but I'm bored and feel like posting. I smashed a rear Ibis S28 rear rim 50 miles out on the White Rim ( doing it in a day ). The wheel _barely_ cleared the frame and had a huge crack in it. Put a tube in and started riding again. I was positive it wouldn't last the remainder of the ride ... but sure enough it did. Take from that what you will ... unclear what the lesson is ( if any). One off stories just don't mean much. Additional info: Ibis replaced free of charge. Oh, and I consider it my fault: Too low air pressure and terrible line choice. Was also running whimpy XC tires for the trip which I'm not used to.


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## Smiles for miles (Feb 26, 2021)

slcpunk said:


> I don't see the relevance, but I'm bored and feel like posting. I smashed a rear Ibis S28 rear rim 50 miles out on the White Rim ( doing it in a day ). The wheel _barely_ cleared the frame and had a huge crack in it. Put a tube in and started riding again. I was positive it wouldn't last the remainder of the ride ... but sure enough it did. Take from that what you will ... unclear what the lesson is ( if any). One off stories just don't mean much. Additional info: Ibis replaced free of charge. Oh, and I consider it my fault: Too low air pressure and terrible line choice. Was also running whimpy XC tires for the trip which I'm not used to.
> View attachment 1936860
> View attachment 1936861


Whoa that's a bad break! Glad to hear it held together and you didn't get stranded in Canyonlands.


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## sergio_pt (Jan 29, 2007)

Probably an aluminum rim would handle the strike better and without cracking? 
I think a good warranty is a must when you ride carbon rims, it's great to have the rims replace for free in case of damage. 
I'm thinking of going with carbon rims but only if they come with good crash replacement warranty.


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## edubfromktown (Sep 7, 2010)

Nope.

Bent a couple of aluminum ones nicely but none of my (three) carbon MTB wheel builds have showed any signs of compromise.

The oldest of those builds are LB carbon hoops from 2014 that have seen a lot of rocky/rooty and urban assault (including staircases) carnage. The newest is on Nextie hoops with Berd spokes.

I'll never forget a Stan's employee telling me (at an MTB event) that I was going to die riding my Light Bicycle carbon rim wheels 

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## Sidewalk (May 18, 2015)

I just took the leap recently and ordered a pair of carbon hoops. I broke the stock carbon hoop on my E29 within weeks of getting the bike, whereas aluminum usually last me a few months of abuse. I am hoping that the heavier duty carbon rims this time around will hold up. If not, back to aluminum.

But I have not had one fail and cause an incident, just the incident cause the failure. A friend of mine went hard over the bars when his wheel exploded when he rolled pretty fast into a reasonably large sized rock just off trail that he didn't see in the weeds. He was not injured, and I am certain the wheel would have failed in some form or another no matter what it was, but the explosion was impressive. We now call that trail "Leonards Rock" (short connector trail).



Smiles for miles said:


> Rim brake rims right? I've heard that heat buildup on those is bad.


I remember one of the selling points of the wheels that came on my roadie is the small amount of aluminum used to dissipate heat from the brake track. 20,000 miles with a lot of climbing, haven't failed yet.


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## Jefflinde (Mar 26, 2015)

sergio_pt said:


> Probably an aluminum rim would handle the strike better and without cracking?
> I think a good warranty is a must when you ride carbon rims, it's great to have the rims replace for free in case of damage.
> I'm thinking of going with carbon rims but only if they come with good crash replacement warranty.


this is the fallacy that many companies hope you fall for. based on this thread and many like it, the chance of actually having a true failure (not just being dumb on your own) is pretty rare. So paying huge amounts of money for a better crash replacement vs buying a less expensive rim option does not make sense. either way you are generally paying for the rebuild of the wheel whether crash replacement or just buying a new rim. so if you can buy a rim at 1/4th to 1/7th the cost of say an ENVE or Reynolds rim by going light bicycle or Nextie, you have to break a lot of rims to ever come out ahead. there is no secret sauce for making rims and the process has been around long enough for everyone that makes them to perfect their process.


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## Shark (Feb 4, 2006)

slcpunk said:


> I don't see the relevance, but I'm bored and feel like posting. I smashed a rear Ibis S28 rear rim 50 miles out on the White Rim ( doing it in a day ). The wheel _barely_ cleared the frame and had a huge crack in it. Put a tube in and started riding again. I was positive it wouldn't last the remainder of the ride ... but sure enough it did. Take from that what you will ... unclear what the lesson is ( if any). One off stories just don't mean much. Additional info: Ibis replaced free of charge. Oh, and I consider it my fault: Too low air pressure and terrible line choice. Was also running whimpy XC tires for the trip which I'm not used to.
> View attachment 1936860
> View attachment 1936861


Impressive that you were able to ride out on that, and also that they replaced it.

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## almazing (Jul 26, 2017)

I've had a set of carbon Crank Bros Synthesis E11 wheels for over 2 years now. I've taken them to my LBS once a year to make sure they're true and the spoke tensions are correct. The 2 times I've taken my wheels in to get checked, the rims were true and like, 3 spokes had to be minimally adjusted. The rims have scratches on the surface, but no cracks. I beat the hell out of these rims and I trust them with my life. 

Carbon rims have come a long way.


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## RS VR6 (Mar 29, 2007)

Smiles for miles said:


> Rim brake rims right? I've heard that heat buildup on those is bad.


I knew someone had that happen on a Zipp 404 carbon clincher rear wheel. The guy blew his rear tire and crashed. He sent the wheels and the rest of the bike to Zipp. After a few weeks...they sent him a new wheel and a new Red groupset.


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## sergio_pt (Jan 29, 2007)

RS VR6 said:


> I knew someone had that happen on a Zipp 404 carbon clincher rear wheel. The guy blew his rear tire and crashed. He sent the wheels and the rest of the bike to Zipp. After a few weeks...they sent him a new wheel and a new Red groupset.


Ok. Not all companies do that, it's positive but clearly product fault.


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## cassieno (Apr 28, 2011)

I have replaced most of my aluminum rims with carbon. The aluminum ones have a decent about of dents in them. The carbon are all hookless and have a wider bead seat (which means a larger / stronger surface area for me to smash things into). I have smashed my Light Bicycle set good it's been fine, my friend collapsed his 6 or so rides in. I now have Reynolds carbon rims but only a few months on them so no real comment on durability. I like that they have a shorter overall height than my LB and seem less likely to catch a rock to the side.


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## edubfromktown (Sep 7, 2010)

Nope. I have two sets of carbon wheels (one I created back ~2014) and ~8 sets of aluminum hooped Stan's rims (some are easily more than 10 years old). None have failed.

The better question might be: has anyone crashed as the result of a poorly built wheel (carbon or otherwise).


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## sergio_pt (Jan 29, 2007)

Daprela did crash hard on a carbon rim... Men's DH race 1 - Snowshoe


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## RS VR6 (Mar 29, 2007)

sergio_pt said:


> Daprela did crash hard on a carbon rim... Men's DH race 1 - Snowshoe


It looks like he might have flatted and his tire came off...in a super rocky part of the trail. I think even with an aluminum rim...he's still walking down the trail.


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## sergio_pt (Jan 29, 2007)

RS VR6 said:


> It looks like he might have flatted and his tire came off...in a super rocky part of the trail. I think even with an aluminum rim...he's still walking down the trail.


I can't tell from the replay. Probably yes it was a flat, the tire didn't hold on to the rim and boom.
He didn't get injured which is a good thing.


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## epiccrosscountry (Jan 8, 2021)

Smiles for miles said:


> Nice when he takes the tire off and rides the rim. I wonder how an aluminum rim would do with those same tests.


gcn did a video doing trail riding without a tire on alloy rims. its pretty much the same, they are indestructible. it took skidding over asphalt to grind it down, and jumping hard to crack the wheel.


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## ferd (Aug 6, 2007)

Yes. I’ve witnessed this. It happens. Definitely should keep an eye on air pressure and run inserts…


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## Aptone (Jun 9, 2020)

Yes, I broke a front carbon rim at the bottom of a roller. It collapsed allowing the front fork to spear the ground and bent the front brake rotor at 90 degrees. I went over the bars but only hit my knee on the stem along the way. The rim was a fat bike rim made in America, and they replaced it free of charge. 

I had been riding those fat rims year round but now just ride fat in the winter. I have a set of 29+ wheels/tires on my Farley now for summer riding.


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