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View Full Version : How to evaluate different carbon technologies/frames? 2018 edition


tylercheung
01-12-2018, 07:05 PM
I've always ridden steel frames, and I think I have a reasonable understanding of the technologies in them - tubing characteristics, parameters, geometries, etc, welding and brazing techniques.

But, it's hard not to hear about carbon fiber/CFRP frames and how they can do all sorts of things from a materials-science point of view that other materials can't achieve and all that. The thing is - it seems like CFRP technologies are changing dramatically year over year, and the typical marketing wording is unrevealing about exactly what has changed or what specific frame characteristic has gotten better - frames are always described as "stiff", "fast to accelerate" but also "more stable" and "takes bumps better" which just seems to be what every frame is supposed to do. There is a plethora of marketing about black box tech/science on tube shaping, compliance, etc. The best I can tell is from some of the press at say, Pez or Cyclingtips through factory tours of certain manufacturers, or by word of mouth. For a while, it seemed the Taiwan (Giant, Merida)/China has had advantages based on scale and R&D innovation, but there seems to be more recently the growth of at least partial or complete in-house CFRP manufacture of mid-size brands (Ridley, BMC), and now local, in-house CFRP shops, Parlee being the pioneer that has always done this for years, but also Sarto, Alchemy, and Allied.

I guess the question is - how can one evaluate the state of CFRP frames as of 2018, the quality of each manufacturer, the viability of the different techniques and technologies used, etc?

dustyrider
01-12-2018, 08:15 PM
Ride them all! :cool:

eddief
01-12-2018, 08:24 PM
with exactly the same dimensions and parts and tires and pedals.

Good luck.

Kontact
01-12-2018, 08:32 PM
I don't think there are really "new technologies" being used. The standard carbon is just being laid up in better ways with more sophisticated designs.

Evaluating them is a little tricky since no one is in complete agreement about what makes a bike fast or efficient. You can point to BB deflection tests, but that only tells you how stiff the BB is in a certain way, not whether it makes the bike "better". And people really don't have a natural sense for what is best over any longer period of time, so they generally favor stiff tires, rigid forks and hard tires until they are told different.

So other than reading ad copy, I don't know how you would really evaluate anything about the actual construction of a CF frame.

bicycletricycle
01-12-2018, 09:29 PM
From a ride quality stanpoint you just have to ride them.

From a safety/reliability/durability standpoint I think it is really important to consider the likely manufacturing variables/errors that coincide with different “technologies” regardless of their theoretical advantages.

Example 1.

Monocoque vs. tube to tube

Monocoque frames are theoretically better but the complex joints they require often lead to voids that go undiagnosed (almost no one X-rays or ultrasounds). These voids lead to lower performance fragile frames.

Tube to tube is a much lower tech way to make frames but the filament wound tubes “never” have voids and even the most basic reinforcement method at the joints (wetting the joint with epoxy and wrapping some unidirectional around it till it is a big ball and then grinding it down later) ensures good compaction and plenty of strength.

Example 2.

High modules fibers

The higher the modulus the more brittle the fiber. Technically a higher modules carbon is higher performance but it also severely limits the shapes that can be achieved, hi-mod fibers in tight bends can snap when being forced into shape and loose a lot of strength. Even if you just use them in the straight part of the tubes they can yield a wall so thin that even though it is strong enough under normal conditions it may be highly susceptible to punctures by debris or just normal “shop wear”.

Cool info from this guy-
https://youtu.be/kJl5V_KTRzc

tylercheung
01-13-2018, 12:33 PM
Yeah, trying to distill things into different variables.

The Taiwanese bikes, i.e Giant/Merida + contracted models from the Europeans, all seem to be monocoque. Maybe they've gotten good enough, or maybe at $800 for complete bikes, they don't care as much.

The in-house layups at Parlee, Sarto, Alchemy, Allied all seem to be tube-tube; the modularity approach probably adds a few grams but lets them fine tune ride characteristics a lot better.

But yea, I guess you'd have to ride them all, but you'd have to find a good bike shop w/ a liberal test ride policy or spend a small fortune...

Kontact
01-13-2018, 12:44 PM
Yeah, trying to distill things into different variables.

The Taiwanese bikes, i.e Giant/Merida + contracted models from the Europeans, all seem to be monocoque. Maybe they've gotten good enough, or maybe at $800 for complete bikes, they don't care as much.

The in-house layups at Parlee, Sarto, Alchemy, Allied all seem to be tube-tube; the modularity approach probably adds a few grams but lets them fine tune ride characteristics a lot better.

But yea, I guess you'd have to ride them all, but you'd have to find a good bike shop w/ a liberal test ride policy or spend a small fortune...
I don't think most of those bikes are properly "monocoque", or one piece formed over bladders. The standard is really the OCLV method, where subassemblies are die molded and joined via tapered overlaps. This method looks like the old monocoque Kestrels, but is functionally more like a tube and lug construction where the lugs are pre-formed. The parts are slip jointed together.

GonaSovereign
01-13-2018, 12:53 PM
Tube to tube is a much lower tech way to make frames but the filament wound tubes “never” have voids and even the most basic reinforcement method at the joints wetting the joint with epoxy and wrapping some unidirectional around it till it is a big ball and then grinding it down later ensures good compaction and plenty of strength.








--> That's not how tube-to-tube joints are made. Grinding through fibers would negate the benefit of the material. You might be thinking of the fillets builders often create between the tubes before they wrap the joints with CF. The joints, made out of DP420 and similar, are sometimes sanded into shape prior to applying the CF.

Here's an example pulled from the internet: that's the epoxy fillet prior to CF application.
http://1.bp.blogspot.com/-pnBDmhPJwyU/UWs81IPifAI/AAAAAAAAAkE/CqrF0J4yaME/s320/BB+Fillet+2.jpg

Cool info from this guy-
https://youtu.be/kJl5V_KTRzc
-->Agreed - Luescher is a great source.

Kontact
01-13-2018, 01:05 PM
--> That's not how tube-to-tube joints are made. Grinding through fibers would negate the benefit of the material. You might be thinking of the fillets builders often create between the tubes before they wrap the joints with CF. The joints, made out of DP420 and similar, are sometimes sanded into shape prior to applying the CF.

Here's an example pulled from the internet: that's the epoxy fillet prior to CF application.
http://1.bp.blogspot.com/-pnBDmhPJwyU/UWs81IPifAI/AAAAAAAAAkE/CqrF0J4yaME/s320/BB+Fillet+2.jpg


-->Agreed - Luescher is a great source.
No, he's talking about a method Calfee uses on odd joins and with their hemp jointed bamboo bikes.

Like this one:
http://www.bikerumor.com/wp-content/uploads/2013/06/Calfee-Factory-Tour-carbon-fiber-bicycle-construction01-600x399.jpg

After grinding they look like this, full of interrupted fibers by plenty strong due to compaction and shear mass.

http://i26.tinypic.com/wjud94.jpg

bicycletricycle
01-13-2018, 01:11 PM
I chose the worst tube to tube method to illustrate the point, grinding through those fibers is defintely harming structure but the amount of extra material present in these types of joints seems to negate these problems. (My evidence being not hearing of or seeing any joints like this fail, I’m sure they do but voids in badly compacted monocoque frames seem to fail way more often even though those frames are “higher performance”)

Lots of ways exist to reinforce tube to tube joints.

--> That's not how tube-to-tube joints are made. Grinding through fibers would negate the benefit of the material. You might be thinking of the fillets builders often create between the tubes before they wrap the joints with CF. The joints, made out of DP420 and similar, are sometimes sanded into shape prior to applying the CF.

Here's an example pulled from the internet: that's the epoxy fillet prior to CF application.
http://1.bp.blogspot.com/-pnBDmhPJwyU/UWs81IPifAI/AAAAAAAAAkE/CqrF0J4yaME/s320/BB+Fillet+2.jpg


-->Agreed - Luescher is a great source.

GonaSovereign
01-17-2018, 07:50 PM
No, he's talking about a method Calfee uses on odd joins and with their hemp jointed bamboo bikes.

Like this one:
http://www.bikerumor.com/wp-content/uploads/2013/06/Calfee-Factory-Tour-carbon-fiber-bicycle-construction01-600x399.jpg

After grinding they look like this, full of interrupted fibers by plenty strong due to compaction and shear mass.

http://i26.tinypic.com/wjud94.jpg

I had blocked that from my memory. Not exactly elegant. Calfee has done much better work...

Bob Ross
01-18-2018, 05:53 AM
Monocoque frames are theoretically better but the complex joints they require often lead to voids that go undiagnosed (almost no one X-rays or ultrasounds). These voids lead to lower performance fragile frames.

Captain Pedantic would like to point out that there's no well-documented correlation between voids in carbon layup and "lower performance" in bicycles. There is certainly the presumption that those flaws [sic] should lead to a lower-quality structure...but so long as the "performance" refers to how that finished structure functions in its intended role (i.e., as a bicycle) rather than as some ideal perfectly fabricated object, the data just isn't there. Carbon bike frames don't necessarily fail because of voids in the layup, nor do bikes without voids ride any faster, longer, or more comfortably than those with.

If it's any consolation, Luescher often seems to make the same presumption that there is correlation...but afaik never backs it up with any evidence.

Kontact
01-18-2018, 06:02 AM
Captain Pedantic would like to point out that there's no well-documented correlation between voids in carbon layup and "lower performance" in bicycles. There is certainly the presumption that those flaws [sic] should lead to a lower-quality structure...but so long as the "performance" refers to how that finished structure functions in its intended role (i.e., as a bicycle) rather than as some ideal perfectly fabricated object, the data just isn't there. Carbon bike frames don't necessarily fail because of voids in the layup, nor do bikes without voids ride any faster, longer, or more comfortably than those with.

If it's any consolation, Luescher often seems to make the same presumption that there is correlation...but afaik never backs it up with any evidence.

A bike is a pretty complicated idea to talk about with simple ideas like performance being more or less on some scale.

But an individual element of a composite structure could certainly be looked at, and if it has voids it is either going to be weak in those areas (leading to failure) or it is going to have to be overbuilt in general to contend with the probability of voids, making it heavy and/or less supple.

So it doesn't seem absurd to say something with flaws in it is going to give up "performance" in use or longevity to a relatively unflawed example. It just won't matter much if it isn't already at the pinnacle of the technology because the cheaper stuff has already given up performance to the high end designs.

fignon's barber
01-18-2018, 06:42 AM
Captain Pedantic would like to point out that there's no well-documented correlation between voids in carbon layup and "lower performance" in bicycles. There is certainly the presumption that those flaws [sic] should lead to a lower-quality structure...but so long as the "performance" refers to how that finished structure functions in its intended role (i.e., as a bicycle) rather than as some ideal perfectly fabricated object, the data just isn't there. Carbon bike frames don't necessarily fail because of voids in the layup, nor do bikes without voids ride any faster, longer, or more comfortably than those with.


I'm picturing Ernesto Colnago, cross section of C50 in hand, pleading for all to look inside his frame, while The Big Bike guys pull further and further away in revenue.

benb
01-18-2018, 07:27 AM
Just figure out what fits you and ride stuff.

A huge amount of the hype is just marketing. There’s a lot less science and engineering going on than what marketing claims. Most of the smaller companies don’t even employ any engineers. The big companies do. There’s more tuning going into the frames from the big companies but the question becomes who did it get tuned for?

It’s like musical instruments or something. There are tons that are really good, but not all of them are going to feel right for you. The bike doesn’t go down the road by itself, it’s what you do with it. So all the marketing/engineering doesn’t matter compared to whether it feels good to you. And no one online can tell you what feels right for you.

bicycletricycle
01-18-2018, 07:52 AM
I guess I was thinking more about big wrinkles , not just small areas of dry fiber or planar voids.

Certainly some types of voids can have a pretty low impact on performance but the claim that voids have nothing to do with a composites structures performance seems silly to me.


Captain Pedantic would like to point out that there's no well-documented correlation between voids in carbon layup and "lower performance" in bicycles. There is certainly the presumption that those flaws [sic] should lead to a lower-quality structure...but so long as the "performance" refers to how that finished structure functions in its intended role (i.e., as a bicycle) rather than as some ideal perfectly fabricated object, the data just isn't there. Carbon bike frames don't necessarily fail because of voids in the layup, nor do bikes without voids ride any faster, longer, or more comfortably than those with.

If it's any consolation, Luescher often seems to make the same presumption that there is correlation...but afaik never backs it up with any evidence.

benb
01-18-2018, 08:20 AM
I guess I was thinking more about big wrinkles , not just small areas of unweeded fiber or planar voids.

Certainly some types of voids can have a pretty low impact on performance but the claim that voids have nothing to do with a composites structures performance seems silly to me.

This is a silly line of discussion cause unless you buy hundreds of bikes and cut them up or x-ray/ultrasound them or whatever there is no way to tell which manufacturers are actually doing the best job. It's all just speculation.

If some magazine or website proceeded to do a test people might not be happy about which brands had higher quality or it might turn things upside down a bit.

dem
01-18-2018, 08:28 AM
I found this video interesting - continuing to confirm my bias that the outsourced mass produced frames are more or less the same and it comes down to paint and branding (and of course the amusing generic china frame having better tolerances.)

https://youtu.be/zryhuHkbb-o

Obviously does not directly address the "material science" angle, but an indicator nonetheless.

bicycletricycle
01-18-2018, 08:45 AM
This is a silly line of discussion cause unless you buy hundreds of bikes and cut them up or x-ray/ultrasound them or whatever there is no way to tell which manufacturers are actually doing the best job. It's all just speculation.

If some magazine or website proceeded to do a test people might not be happy about which brands had higher quality or it might turn things upside down a bit.

In my original post I explained why it is not a silly line of discussion. Some methods of making a frame tend to yield certain types irregularities. It Is true that you will not be able to non destructively test each frame so you won't know if they are manifest in the particular unit you are considering.

The question was how to evaluate the technologies available in bicycle frames, one way is to know what kind of errors those technologies tend to cause. This is just one element to consider when choosing a frame.


One other thing to consider might be the types of inspection the manufacturer does before shipping. I believe canyon x rays their forks before shipping them.

jemoryl
01-18-2018, 08:55 AM
Luescher is someone who repairs a lot of CF so he clearly gets to see what defects are associated with failure. Still, it isn't clear to me if voids play a statistically significant role is said failures.

The OP mentioned that Ridley and BMC are now making frames in house. Really? I recall BMC having elaborate plans to build a high tech fabrication facility in Switzerland, but that there were problems bringing it online. Anyone know the latest? The BMC frame that Luescher cuts up was a pretty sloppy piece....

benb
01-18-2018, 09:11 AM
In my original post I explained why it is not a silly line of discussion. Some methods of making a frame tend to yield certain types irregularities. It Is true that you will not be able to non destructively test each frame so you won't know if they are manifest in the particular unit you are considering.

The question was how to evaluate the technologies available in bicycle frames, one way is to know what kind of errors those technologies tend to cause. This is just one element to consider when choosing a frame.


One other thing to consider might be the types of inspection the manufacturer does before shipping. I believe canyon x rays their forks before shipping them.

But is any of this really going to affect your experience? This is 0.001% stuff that is silly to worry about unless everything else is already in place. Who worries about this stuff?

You can't do anything except take their word for it and it's all marketing. Some methods of construction might be more prone to certain types of flaws but the manufacturing quality + QC at a given company/outsourced factory is going to have more to do with the final quality than the production method employed. And in terms of performance the only thing that matters would be how it feels when you ride it. If I ride it and don't like it that shouldn't affect your judgement much if at all, and it should affect your judgement any more if some famous rider/racer rides it and pronounces it good or bad.

If you're worried about flaws choose your frame based on warranty quality + reputation of the manufacturer for customer service with failed frames. Which would probably imply go with the big manufacturers that have a heavy presence in your location. Small shops could disappear and brands which are not highly prevalent in your location can decide to pack up shop or change distributors or something like that and be a PITA. Or just make you go through a different company that they outsource service to in a particular country.

If the frame was going to fail I'd much rather it be a Trek than something like a Canyon that has a much smaller and/or non-existent support network. I had a BH, even dealing with getting a small part for that thing was a PITA, stuff I could have walked into any Trek/Specialized dealer and had the part (possibly free) all over the US. Same thing with a 1-man shop. Some are good, some are worse, some disappear before the life of the frame is over.

Realistically anything high quality has a low chance of flaws/failure anyway.

bicycletricycle
01-18-2018, 10:33 AM
1. I don't think of frame failures as a fiscal issue, I think of them as a safety issue. The reason why I don't want a joint to fail on my bike isn't the risk of loosing money, it is the risk of damaging my health. a "0.001%" increase in breaking my neck is important for me to consider.

2. I disagree with your statement-
"You can't do anything except take their word for it and it's all marketing."

It is true that carbon frames are a black box to some extent, most of us have no way to directly analyze the actual carbon used, how accurately each layer was placed, how many voids, etc..... But to say that we have no way to evaluate the frames other than riding them is wrong. You can learn about the processes used (many companies make videos showing their processes), you can make note of trends in failures from different brands, you can talk to the people who make these frames (many are friendly and you can watch youtube videos of people cutting them apart. Does this make you an engineer? No. Does it give you more ways to evaluate a purchase, Yes.

3. "But is any of this really going to affect your experience?" Obviously not for you, however, piece of mind is part of my experience. Plus, learning about all the details is fun for me so it actually adds to the experience.



But is any of this really going to affect your experience? This is 0.001% stuff that is silly to worry about unless everything else is already in place. Who worries about this stuff?

You can't do anything except take their word for it and it's all marketing. Some methods of construction might be more prone to certain types of flaws but the manufacturing quality + QC at a given company/outsourced factory is going to have more to do with the final quality than the production method employed. And in terms of performance the only thing that matters would be how it feels when you ride it. If I ride it and don't like it that shouldn't affect your judgement much if at all, and it should affect your judgement any more if some famous rider/racer rides it and pronounces it good or bad.

If you're worried about flaws choose your frame based on warranty quality + reputation of the manufacturer for customer service with failed frames. Which would probably imply go with the big manufacturers that have a heavy presence in your location. Small shops could disappear and brands which are not highly prevalent in your location can decide to pack up shop or change distributors or something like that and be a PITA. Or just make you go through a different company that they outsource service to in a particular country.

If the frame was going to fail I'd much rather it be a Trek than something like a Canyon that has a much smaller and/or non-existent support network. I had a BH, even dealing with getting a small part for that thing was a PITA, stuff I could have walked into any Trek/Specialized dealer and had the part (possibly free) all over the US. Same thing with a 1-man shop. Some are good, some are worse, some disappear before the life of the frame is over.

Realistically anything high quality has a low chance of flaws/failure anyway.

oldpotatoe
01-18-2018, 10:49 AM
I've always ridden steel frames, and I think I have a reasonable understanding of the technologies in them - tubing characteristics, parameters, geometries, etc, welding and brazing techniques.

But, it's hard not to hear about carbon fiber/CFRP frames and how they can do all sorts of things from a materials-science point of view that other materials can't achieve and all that. The thing is - it seems like CFRP technologies are changing dramatically year over year, and the typical marketing wording is unrevealing about exactly what has changed or what specific frame characteristic has gotten better - frames are always described as "stiff", "fast to accelerate" but also "more stable" and "takes bumps better" which just seems to be what every frame is supposed to do. There is a plethora of marketing about black box tech/science on tube shaping, compliance, etc. The best I can tell is from some of the press at say, Pez or Cyclingtips through factory tours of certain manufacturers, or by word of mouth. For a while, it seemed the Taiwan (Giant, Merida)/China has had advantages based on scale and R&D innovation, but there seems to be more recently the growth of at least partial or complete in-house CFRP manufacture of mid-size brands (Ridley, BMC), and now local, in-house CFRP shops, Parlee being the pioneer that has always done this for years, but also Sarto, Alchemy, and Allied.

I guess the question is - how can one evaluate the state of CFRP frames as of 2018, the quality of each manufacturer, the viability of the different techniques and technologies used, etc?

I think that's the issue...many different ways to make carbon fiber bike frame. Threads per inch, thickness, orientation, layup, method to hook it all together, tube diameter, shapes, etc, etc....why each is different..and how they all say they are 'tuned to the rider''..tuned to whom?

Only way to 'know' is to have an extended test ride on one...and that's pretty hard to impossible(with some one at a time customs)..a ride around the parking lot does not a 'test ride' make. Asking for opinions can help but that's subjective, 100%..what's 'stiff' to one guy is 'compliant' to another.

So, what to do..you eval on price, fit and looks and hope for the best....:)

tylercheung
01-25-2018, 11:55 AM
I think that's the issue...many different ways to make carbon fiber bike frame. Threads per inch, thickness, orientation, layup, method to hook it all together, tube diameter, shapes, etc, etc....why each is different..and how they all say they are 'tuned to the rider''..tuned to whom?

Only way to 'know' is to have an extended test ride on one...and that's pretty hard to impossible(with some one at a time customs)..a ride around the parking lot does not a 'test ride' make. Asking for opinions can help but that's subjective, 100%..what's 'stiff' to one guy is 'compliant' to another.

So, what to do..you eval on price, fit and looks and hope for the best....:)

Sigh...I think I'm just going to meditate and maybe upgrade the gruppo on my steel bike!

Kontact
01-25-2018, 12:25 PM
Sigh...I think I'm just going to meditate and maybe upgrade the gruppo on my steel bike!

I think the problem is that you want to know about the ingredients, but really it is about the meal. If a bike has good specs and is well reviewed, why do you need to know the layup method or modulus number used in construction to want to ride one?

tylercheung
01-25-2018, 12:46 PM
I think the problem is that you want to know about the ingredients, but really it is about the meal. If a bike has good specs and is well reviewed, why do you need to know the layup method or modulus number used in construction to want to ride one?


yeah, kind of like in some recent podcast, someone was talking about the coffee...good beans are all good, but some people shop more on the narrative, the single-origin family farm that's been growing beans in the same way for the past 30 years, etc...

Kontact
01-25-2018, 03:19 PM
yeah, kind of like in some recent podcast, someone was talking about the coffee...good beans are all good, but some people shop more on the narrative, the single-origin family farm that's been growing beans in the same way for the past 30 years, etc...

If that's your thing, buy a handmade carbon bike made in a workshop you like. Parlee custom, Calfee, etc. It may or may not be "ultimate", but it will have a good story.