paging dr. woo...dr. woo to the er plz

iRider said:

What you are saying makes me wonder why we don't see more broken frames and parts. Are they constructed with enough 'meat' that this doesn't matter or is the industry just lucky that not many ride their bikes hard enough?
I know in my local shop quite a few broken carbon frames are returned every year and from all manufacturers. Curious if anybody has a number on what percentage actually fails?

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dump said:

People with those numbers have a vested interest not to share them. Everyone I know with a carbon frame that rides hard has had to warranty the frame at least once. A buddy of mine had one every season for 3 seasons... the 3rd one he's on however is still running (i think).

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Harry BarnOwl said:

Sorry for the late reply, was away on holiday.

See attached a picture of a cross section of a downhill carbon bar of one of the "premier" leading brands. The cut was taken through the middle of the clamping section. If you need further explanation of why this is terrifying:

1. The cross section isn't even close to round. The laminate thickness is varying by a huge percentage in places, most likely due to incomplete consolidation; this is the part of the process where the laminate is compressed to squeeze air and excess resin out to get your correct fibre volume fraction. Why is this important? Because a) the material properties (strength/stiffness) you designed the thing to work with depend on (now it's potentially weaker than you thought it was going to be) and b) see part two below.
2. Voids. Lots of them. This is where you haven't got all of the air out during consolidation. These are stress concentrations and points of delamination waiting to happen.
3. Hard to tell without actually checking all of the fibre angles, but it looks like they've used more than 4 plies pointing in the same direction and that the laminate isn't truly symmetric and balanced. I don't really have the time to go into detail as to why this is bad but it's poor design practice in composites.

I've personally seen 4 of these particular bars go, two at the stem clamping area and two at the rise. I wasn't surprised when they did and I think it's kind of criminal that these things are being sold to people. Yes, there probably are lots of them out there that haven't cracked or snapped yet but do you really want to play the lottery when it comes to your handlebars being intact when you have a heavy landing or a crash?

Beyond the manufacturing related issues above, bare in mind that, unless you go with very fancy materials, carbon fibre composites exhibit no ductile behaviour beyond yield. This means that when they yield, they do so with no bending/necking before they rupture and therefore no warning too. Based on this alone, I think they're an extremely poor choice for making handlebars out of as they're such a safety-critical component. You snap a chainstay/seatstay? Fair enough, you could probably still ride it out. You snap your bars and you roll the dice.

If you want to go light up front, go for Ti or something.

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iRider said:

What you are saying makes me wonder why we don't see more broken frames and parts.

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maxyedor said:

How does that compare to their frame destruction frequency with Al, and why are they not back on Al?

It seems like the guys I know who ride hard, really hard, break everything. So while I agree that carbon aint all it's cracked up to be, I think there may be other factors at play, like a complete lack of engineering prowess or maybe bike companies are just run by the bean counters and replacing 1 out of every 100 frames is totally fine as long as they can save $50 on every frame they build.

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SylentK said:

I think the thing here is, we assume the lizard people know what they're doing. When probably in reality, they don't.

Marketing Lizard: "We need crabon frames!"
Engineering: "Cool! But you know what, to do it right, it'll make a frame retail for like a million dollars"
Marketing: "Well how does Santa Cruz pull it off, then?"
Engineering: "Good question, guess we'll just pick a Chinese crabon manufacturer and just go with what they say. As long as it passes our random QC tests that don't mimic actual riding stresses, we should be fine."
Sales Lizard: "Do you think we can figure out a way to charge more for frame because we say it uses different crabon technology?"
Engineering: "You bet! What about warranty? You know, just in case..."
Bean Counters: "As long as you guys sell enough frames to pay off the cost of the molds, you know, capital expenses...Break away!"
Sales: "Hmmm...$3500 for a frame it is then."

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syadasti said:

On a related note:
https://www.pinkbike.com/news/5-custom-evil-wreckoning-cancer-fundraiser2.html

Who is going to protect the workers making all the carbon fiber parts on this contest prize? F cancer, except for the poor workers who make your business possible in the cheapest possible factories you've outsourced to in Asia. What a great contest for the privileged to make them feel good about themselves while they outsource their cancer to the poor in Asia.

Also recycling carbon fiber, forget about it. At least we have profitable plastic bikes now.

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Tantrum Cycles said:

Now I suppose you're going to bring up "ocean fill". What a quaint new term for dumping scraps and resin into the ocean. Who's getting cancer NOW?????

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After a microfiber study of the Seine River in 2014, Bruno Tassin, an urban hydrologist at University of Paris-Est, faced the same dilemma: tons of pollution without definitive point source. So he conducted a follow-up in Paris in 2016 to determine if microfibers clouded the atmosphere. Tassin found that three to ten tons of microfibers rain out of the air onto the 1,098-square-mile region surrounding Paris, each year.

“We don’t know how they move through the air. There is a probable link between production and fallout, but we don’t know precisely,” said Tassin. But Tassin thinks other sources, such as ground runoff, might still play a role.

Pollutants and other fine particles can hang in the air and travel great distances, said George Thurston, who studies the health effects of air pollution at New York School of Medicine. These airborne fibers can also be toxic. During the industrial revolution, byssinosis or brown lung disease, befell textile plant workers due to cotton or other fibers in the factory’s air. But Thurston said more research is needed to ascertain how microfibers get around.

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syadasti said:

On a related note:
https://www.pinkbike.com/news/5-custom-evil-wreckoning-cancer-fundraiser2.html

Who is going to protect the workers making all the carbon fiber parts on this contest prize? F cancer, except for the poor workers who make your business possible in the cheapest possible factories you've outsourced to in Asia. What a great contest for the privileged to make them feel good about themselves while they outsource their cancer to the poor in Asia.

Also recycling carbon fiber, forget about it. At least we have profitable plastic bikes now.

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syadasti said:

The air too, even in first world countries that are more regulated than the US:



More on the topic in video form:

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Tantrum Cycles said:

that video made me a little constipated

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syadasti said:

Also recycling carbon fiber, forget about it

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maxyedor said:

Most people will never break a frame, but they will put the bike on a scale.

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dcamp29 said:

So true. I've managed to break/crack almost all my frames in the last 5 years. My evil wreckoning hasn't cracked (that I can find), but weighs 2lbs more than a comparable Trek frame which I did break the year prior.

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FlipSide said:

- It seems I had much more chance than everybody else for Crank Brothers pedals. I have 10 years old Candy still in use on my main bike.

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FlipSide said:

- I still use the same Reverb post from 2012 (been fully serviced once in 2015)

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FlipSide said:

I have my lift pass at MSA.

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slyfink said:

oh, you're in the National Capital area?! Tell me about les Sentiers du Moulin.... I keep hearing VBDN is an alternative to Vermont, but all I ever read about is the Neilson... and I'm not really into epic cross country rides. If I'm going to drive for 5 hours to go ride, I want epic gnar! I like to go up only to access good descents. It seems like SDM fits the bill.... is that correct?

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jonKranked said:

i still have a functioning crank bros joplin. in 2017. we must be in some sort of insane alternate reality. and i have a pair of OG mallets that still work fine.

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dcamp29 said:

Having made a list it seems like my bikes get crashed and broken mostly from that. I do remember my aluminum Patrol had a massive dent on the belly of the DT and I kept riding it for a long time. I think I should be on metal bikes.

2014
Carbon Remedy (cracks in rear end)
Carbon Slash 27.5- chainstay cracked and seatstay fully buckled when crashed into rocks)

2015
Aluminum Transition Patrol (cracked chainstay- rode it anyways, sold with new chainstay)

2016
Carbon Evil Following (smashed seat-stay when ghost rode into rocks)

2017
New Carbon Remedy (seatstay cracked bad- replaced that, then put rock through downtube)

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Tantrum Cycles said:

You guys are the guys that get the rare parts that have every single thing in tolerance....

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StiHacka said:

So what qualifies someone to become a designer in the bike industry?

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atrokz said:

I think all the following answers sufficed

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slimshady said:

This might help:

https://nsmb.com/articles/ask-uncle-dave-can-i-be-bike-designer/

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atrokz said:

pretty funny. this stood out: " And none of that even matters, because everybody knows that the most important work necessary to build bikes all happens in the marketing department."

One thing is designing a bike, the other is developing the process and methods for manufacturing to ensure the idea becomes a true reality. Which seems to be the missing link with literally all of these companies. You need manufacturing engineers to make manufacturing process and methodology decisions, not mechanical engineers. I have yet to meet a mechanical engineer that truly understands this blind spot.

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Tantrum Cycles said:

We have yet to have the pleasure of meeting. The problem you refer to is because most mechanical engineers never make ANYTHING. EVER!. Half of them never turned a wrench. The ones that have are at a huge advantage in terms of designing something that actually works....or that you can work on.

i was lucky enough to be a heavy line auto mech for a few years, thrown in with generator mech in the AF and motorcycle shop wrench. throw in a little lathe and mill work and I knew a lot before I even went to school at age 23.

Afterward, I was lucky enough to work for race car mfg that actually made their own chassis. And I've seen the worst engineering thru all of it, for the very reasons you stated. unmakeable, unusable stuff.

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jonKranked said:

in my industry, most drawing changes occur because of the manufacturing engineers during design transfer.

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Tantrum Cycles said:

for better or worse?

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Tantrum Cycles said:

We have yet to have the pleasure of meeting. The problem you refer to is because most mechanical engineers never make ANYTHING. EVER!. Half of them never turned a wrench. The ones that have are at a huge advantage in terms of designing something that actually works....or that you can work on.

i was lucky enough to be a heavy line auto mech for a few years, thrown in with generator mech in the AF and motorcycle shop wrench. throw in a little lathe and mill work and I knew a lot before I even went to school at age 23.

Afterward, I was lucky enough to work for race car mfg that actually made their own chassis. And I've seen the worst engineering thru all of it, for the very reasons you stated. unmakeable, unusable stuff.

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jonKranked said:

in my industry, most drawing changes occur because of the manufacturing engineers during design transfer.

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atrokz said:

This is how it goes. As a manufacturing engineer, we tend to see a lot of 'ideas' like square holes and zero rad edges. Shit, the stuff I could list if I wasn't still tied to NDA by a former defense contractor would boggle some minds.

Landing gear now, so far a LOT better but that's probably because most of these designs go through dozens of people before making it to me. But still, if it's an R&D program for a new jet, there's tons of 'great' designs that need adjustment and insane tolerances that are nearly impossible to meet, or takes $$$$ to find solutions to do so.

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jonKranked said:

our product designers are actually pretty good. generally the changes aren't because "we can't make that" but more "well, if you change this we could make it faster and improve throughput/yield/etc"

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dump said:

He didn't destroy any previous aluminum frames that I'm aware of. He's still on carbon in part because they kept offering him replacements... he did consider going back to aluminum after the 2nd breakage... but they promised him a new improved model and that seems to have been working for 2-3 seasons... so there's that. I have to imagine the numbers on some models of frame are way over 1 out of 100 come back for warranty. Then again, who knows how many people actually ride their frame for real.

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