More on deep aero carbon tubeless rims.

cyclintom · Feb 27, 2019

During the last episode before several people thought changing the subject was more important than the subject, I explained that I had got a set of deep aero carbon clincher rims. These worked very well. And because of the increased aerodynamics of the rims they didn't react to even strong side gusts the way aluminum aero wheels do - aluminum being difficult to get a really clean aero shape on.

I had bought a set of Fulcrum aluminum wheels and they came preset-up for tubeless operation so I tried it. And I REALLY like tubeless tires. On the very first ride I hit some large stone or piece of glass in the road large enough for the tire to bump-bump-bump until I reached down and knocked it off.

I stopped to look at it and the sealant had sealed the hole and no pressure was lost. The road I was on was very narrow and there was a lot of traffic on it so I appreciated not having to change out tubes on a narrow road.

So after getting the carbon wheels and liking them they started advertising a tubeless version and I decided to get them. From China these things are CHEAP. It is very difficult to get wheels this cheap anywhere else.

I ordered a set and after they came in I mounted a set of Michelin Pro4 Endurance tires on them. I don't know where I originally got these but they were advertised as being able to be clinchers or tubeless. If you EVER see this do not believe it. Presently Michelin doesn't make any tubeless tires and they are significantly different than clinchers around the bead. If they do not specifically say "tubeless" they are not.

In any case, inflating them caused a one of them to go completely out of true - over an inch! And the other made a large 'BANG'ing sound and upon further investigation it had delaminated along the bead edge of the rim.

I bought a similar set from another Chinese supplier and they delaminated even more drastically at only 80 psi.

When you're buying these sorts of cheap parts they can always be really good like the clincher version or they can turn out to be dudes. I take my chances. In any case I got repayments for these wheels and those two suppliers disappeared off of Ebay.

Here it is perhaps 4 or 5 months later and they turned up again offering a slightly different but similar wheel for a better price. The other wheels delaminated obviously because the Pre-preg cloth they used was set down in layers and not allowed sufficient time to harden.

Yesterday, the newer wheels came in and I had already gotten the latest Continental GP5000TL (the only tubeless tires Continental makes so far). Actual tubeless tires mount EASIER to the tubeless wheels than the clincher tires do. Also after you make sure that the tire is correctly and straightly mounted you can pump them right up with a normal floor pump.

So these wheels have gone right together without a flaw. I intend to be very careful with them in case they still have any weaknesses in them but if they perform like the clincher wheels I will be more than happy.

By the way. I have built a whole lot of wheels in my time riding bikes. Just a couple of years ago after a long layoff, I broke an old fashion rim. I had another set of wheels with the same sort of rims but the hubs were shot. I pulled a rim off of one of those wheels and respoked it on the new wheel and trued and tightened it in less than an hour. So I do know what I'm doing.

But you CANNOT do this with carbon wheels. The spoke beds are uneven and so you cannot thread the spokes in all to the same depth and then tighten them from there. On aluminum wheels you have this screwdriver with a wiggle in it so that you can go around the rim and rapidly turn all of the nipples down to exactly the same depth and go from there. But on carbon rims you cannot do this because there can be 2 mm different in nipple depth. These wheels are normally built on an automatic machine that adjusts all of the spokes up to the proper tension using a torque machine that tightens all of the spokes up at once.

So while I suppose if you were REALLY good and patient that you could build a carbon rim into a wheel it would be days of labor and after trying it myself I would suggest buying a new wheel since they're cheaper than the time you'd put into trying to build one yourself.

I'll update you as I go along concerning these wheels.

BrianNystrom · Mar 2, 2019

Tom, I take it you haven't heard the old expression "once bitten, twice shy"?

You bought junk wheels that could have gotten you seriously injured if they had failed while you were riding, then you went out and bought more of them? Really? There's another saying; "insanity is doing the same thing over and over, and expecting a different result". Come on man, you should know better!

A 2mm variation in the spoke bed thickness indicates a serious quality problem! That does not happen with quality carbon rims! Ever! It doesn't matter where they're made, if they're properly constructed they are every bit as consistent as aluminum rims. To act as if this is just par for the course for carbon is not only wrong, it's dangerous.

For your own good, please stop buying this junk before you end up in the hospital...or worse.

Also, please post the names of the vendors so others here will know not to buy their products.

cyclintom · Mar 3, 2019

BrianNystrom said:
Tom, I take it you haven't heard the old expression "once bitten, twice shy"?

You bought junk wheels that could have gotten you seriously injured if they had failed while you were riding, then you went out and bought more of them? Really? There's another saying; "insanity is doing the same thing over and over, and expecting a different result". Come on man, you should know better!

A 2mm variation in the spoke bed thickness indicates a serious quality problem! That does not happen with quality carbon rims! Ever! It doesn't matter where they're made, if they're properly constructed they are every bit as consistent as aluminum rims. To act as if this is just par for the course for carbon is not only wrong, it's dangerous.

For your own good, please stop buying this junk before you end up in the hospital...or worse.

Also, please post the names of the vendors so others here will know not to buy their products.

What do you do for a living Brian?

BrianNystrom · Mar 3, 2019

Technical writing, instructional design and training. Why?

cyclintom · Mar 3, 2019

Because I'm wondering why you make those sorts of comments that are somewhat outside of your expertise. We could publish pictures of failed carbon fiber bikes off of the Internet all day long and I'm wondering if you ride a CF bike. If so, why would that be? Surely as a tech writer it would occur to you that any and all materials have a learning curve and even steel frames were fairly dangerous when they started making high performance racing bikes out of thin steel. I saw several Reynolds 531 frames that had what was plainly fatigue failures. Would you argue that steel was too dangerous to use?

Aluminum frames have a much shorter fatigue life than carbon fiber. Would you therefore claim them too dangerous to ride?

It is difficult these days to get a steel bike made without a carbon fiber fork. My very serious injury was due to a carbon fiber fork exploding and dropping me on my head at a mere 5 mph and while I was bending over to look at the speedo pickup to see why it was clicking. So that was only from perhaps 2 feet. Inspection of the fork showed that it was improperly made - it used an aluminum head on the fork and CF legs. One of the legs wasn't even glued on and I had done 4,000 miles on it before it came off. That caused the other leg to break from overload. That was built in Ireland. Should I condemn all carbon fiber forks for that?

The original carbon 50 mm deep rims I got were clinchers and they have performed flawlessly. I then bought two sets of Chinese tubeless wheels and both sets failed in exactly the same manner - delamination. I returned these and got refunds. Those sellers disappeared off of Ebay for 6 months and turned up with a slightly different sets.

I bought a set and building these up showed the same bullet proof design of the clinchers. Obviously the problem was with the pre-preg layers not being properly cured.

Now I will show you a picture of a Colnago C40 frame that fell apart without warning and also at only 5 mph. The owner broke a couple of fingers in his hand in the resulting fall and the complex surgery caused the ligaments to attach to the bones so that he now cannot move his small finger at all. Would you condemn Colnago's workmanship or the material for this failure? These failures were at the strongest part of the C40 frame - the head lugs.

BrianNystrom · Mar 3, 2019

I guess you've decided to go off the deep end again.

The fact that I don't work in the composites industry doesn't mean that I don't know anything about composites. That's an utterly asinine thing to assert. As usual you're jumping to uninformed conclusions about people you don't even know.

If you want to play that stupid game, I guess you can't know anything about bicycles because you never worked in the bike biz. I have. For that matter, you don't work in the composites industry, either.

Since you asked, I have four CF bikes and CF forks on 4 others, two of which have CF wheels. I know the difference between quality composites and junk. Apparently, for all of your supposed engineering knowledge, you don't.

cyclintom · Mar 4, 2019

BrianNystrom said:
I guess you've decided to go off the deep end again.

The fact that I don't work in the composites industry doesn't mean that I don't know anything about composites. That's an utterly asinine thing to assert. As usual you're jumping to uninformed conclusions about people you don't even know.

If you want to play that stupid game, I guess you can't know anything about bicycles because you never worked in the bike biz. I have. For that matter, you don't work in the composites industry, either.

Since you asked, I have four CF bikes and CF forks on 4 others, two of which have CF wheels. I know the difference between quality composites and junk. Apparently, for all of your supposed engineering knowledge, you don't.

Can you inform us all how you know the difference between "quality" composites and junk since that particular feature eluded the industry for quite some time.

BTW, I did work in the bike business when between research and development engineering jobs. In fact I done so many different jobs that it would make your head spin. And I was successful in every one of them.

BrianNystrom · Mar 4, 2019

cyclintom said:
Can you inform us all how you know the difference between "quality" composites and junk since that particular feature eluded the industry for quite some time.

Nonsense. Composite technology has evolved over the decades, but the fundamentals of quality haven't changed. A product like the rims you mentioned that have ridiculous amounts of variation is obviously poorly made junk. If you can't see that, there's no hope for you.

BTW, I did work in the bike business when between research and development engineering jobs.

Good for you, I stand corrected on that point.

[/QUOTE]In fact I done so many different jobs that it would make your head spin. And I was successful in every one of them.[/QUOTE]
No, it wouldn't, as I've done the same thing. Everything from retail to Automated Optical Inspection equipment, to software, to financial services and a bunch of others. So what?

If you can't tell that a carbon rim with a 2mm or more variation in the spoke bed thickness is a piece of ****, you apparently didn't learn much from your work experience, or engineering school for that matter.

cyclintom · Mar 4, 2019

BrianNystrom said:
Nonsense. Composite technology has evolved over the decades, but the fundamentals of quality haven't changed. A product like the rims you mentioned that have ridiculous amounts of variation is obviously poorly made junk. If you can't see that, there's no hope for you.

the fact that you would say something like that makes me suspicious about what you did in the "composite" business. There is absolutely NO WAY of controlling thickness and voids inside the turn of an aero rim using pre-preg and inflatable molds. Or are you suggesting that American manufacturers are hand laying up carbon cloth one layer at a time?

BrianNystrom · Mar 4, 2019

Instead of putting your ignorance on display here for all to see, spend some time online watching how carbon rims are made.

cyclintom · Mar 4, 2019

BrianNystrom said:
Instead of putting your ignorance on display here for all to see, spend some time online watching how carbon rims are made.

I should have realized that your entire "experience" with carbon rims was with an internet video.

BrianNystrom · Mar 4, 2019

Only in your addled, twisted mind, Tom.

I should have remembered that actually learning about something before you go spouting off about it is a foreign concept to you. It's easier for you to just make up a bunch of **** and pretend you know what you're talking about.

cyclintom · Feb 4, 2023

Brian, why do you persist in implying that you know anything at all about composites? There is NO carbon fiber bike on the market today that hasn't broken. When pro teams are suing their team bike suppliers as EOS did one might get the idea that after 30 years, composite construction of complex shapes is hardly settled science. There is no composite frameset other than Time that I am aware of that haven't had failures. And Time uses layers of Vectran in their construction and not 100% carbon fiber. You are welcome to your personal opinions but please don't pretend that they are fact. I spent 50 years as an engineer actually doing things and not reading about them.

cobbwheels · Feb 5, 2023

cyclintom said:
Brian, why do you persist in implying that you know anything at all about composites? There is NO carbon fiber bike on the market today that hasn't broken. When pro teams are suing their team bike suppliers as EOS did one might get the idea that after 30 years, composite construction of complex shapes is hardly settled science. There is no composite frameset other than Time that I am aware of that haven't had failures. And Time uses layers of Vectran in their construction and not 100% carbon fiber. You are welcome to your personal opinions but please don't pretend that they are fact. I spent 50 years as an engineer actually doing things and not reading about them.

When I watched a video of how CF frames are made, I was wtf! They're using thin sheets stuck together like tape. I assumed it's good enough...

But I'm still worried for the epoxy matrix of CF. I've dealt with CF before with RC helicopters. I crashed these often enough so I'm familiar with the failure mode. CF can be very stiff. I have sometimes deliberately broke them on purpose to see how much punishment they can take. It's usually the epoxy resin that fails first before the fibers. I have broken CF parts where the fibers are still intact but have delaminated and the resin cracked. These are well-made parts after all, they're so basic and simple unlike bike parts.

A CF is well known for its stiffness to weight ratio but in failure testing, the epoxy resin presents a major weakness. It will crack and the crack can progress almost instantly. There's nothing the fibers can do at that point, they just pop out or delaminate.

Anyway, I'm also an engineer but only for 6 years and then bonked my career. My life has been a disaster after another since that. But from a failed engineer to a highly successful one like yourself, I can understand your distrust of CF.

BrianNystrom · Feb 5, 2023

cyclintom said:
cyclintom said:

Brian, why do you persist in implying that you know anything at all about composites? There is NO carbon fiber bike on the market today that hasn't broken. When pro teams are suing their team bike suppliers as EOS did one might get the idea that after 30 years, composite construction of complex shapes is hardly settled science. There is no composite frameset other than Time that I am aware of that haven't had failures. And Time uses layers of Vectran in their construction and not 100% carbon fiber. You are welcome to your personal opinions but please don't pretend that they are fact. I spent 50 years as an engineer actually doing things and not reading about them.

Click to expand...

So, let's see. After nearly four years, you crawl out from under your rock just to attack me? Why am I not surprised?

Let's get one thing straight. I NEVER said anywhere that carbon fiber bikes never break, you just made that up. Of course there will be failures, just as there are with steel, aluminum and Ti bikes. No bike is 100% impervious to breakage.

That said, it doesn't make your previous rants any less insane, nor does it mean that you actually know what you're talking about now. If you want to keep beclowning yourself, that's your call, but nobody is going to take you seriously until you stop making things up and start presenting cogent arguments. If you decide to keep "poking the bear" so to speak, I - and I assume others here - will be more than happy to refute any misinformation you post, so that others people reading these threads don't make bad decisions based on your nonsense. It's tedious, but someone needs to do it for the good of the other forum participants.

cyclintom · Mar 5, 2023

This conversation was some time ago. I see that parts of it were construed as offensive and if you felt that personally let me appologiz4e. But comments about Chinese wheels being junk and $2000 wheels being quality were entirely out of line since the Chinese MADE the $2,000 wheelsets. Worker were coming in after hours using the same molds and the same materials to make the same wheels without the brand names on them. I bought some carbon wheels with aluminum brake surfaces for less than $400 that were Campy Bellas I believe they were called. These were being sold from Campy for $3,500. Aside from the price what was the difference? While in most things, price does equate more or less to quality, there is very little connection in carbon fiber parts since you can have a void in a Pinarello frame the same as with the Chinese el cheapo. And there little chance of one being any better than the other since they are made out of the same sort of molds and the Chinese invented the manufacturing process.

And while carbon fiber components are improving the resin that holds them together is not. Over time it hardens and becomes brittle.

cyclintom · Mar 5, 2023

cobbwheels said:
When I watched a video of how CF frames are made, I was wtf! They're using thin sheets stuck together like tape. I assumed it's good enough...

But I'm still worried for the epoxy matrix of CF. I've dealt with CF before with RC helicopters. I crashed these often enough so I'm familiar with the failure mode. CF can be very stiff. I have sometimes deliberately broke them on purpose to see how much punishment they can take. It's usually the epoxy resin that fails first before the fibers. I have broken CF parts where the fibers are still intact but have delaminated and the resin cracked. These are well-made parts after all, they're so basic and simple unlike bike parts.

A CF is well known for its stiffness to weight ratio but in failure testing, the epoxy resin presents a major weakness. It will crack and the crack can progress almost instantly. There's nothing the fibers can do at that point, they just pop out or delaminate.

Anyway, I'm also an engineer but only for 6 years and then bonked my career. My life has been a disaster after another since that. But from a failed engineer to a highly successful one like yourself, I can understand your distrust of CF.

The material is called "prepreg" and it is made out of sheets of carbon fiber impregnated with a type of resin that is cured enough not to be sticky but not completely cured. They stack as many of the prepreg together as necessary for the application put it in the mold and in some cases like wheels, they put a sepa4ration layer or a balloon in between them. They close the mold, inflate the balloon or in some case use high pressure air so push the separate sides of the layers into place and then heat them to a temperature that sets the resins. Never-the-less, there always the possibility of contaminants getting on the surfaces which consequently do not adhere to each other causing a slight separation or "void"

This is where very high tension forces can occur and where cracks in the layup can develop.

Time bicycles fights this by using an additional layer of Vectran which is a man-made thread that is of similar strength to carbon fiber. But whereas carbon fiber is short fiber length, Vectran is long threads. This allows the material to contact a great deal more of the resin and hold the layup together very much longer. While I would trust the best carbon fiber for more than 10 years, Time's method can probably go for 30 years. But MAN are they rigid. My Time could NOT be ridden with 23 mm tires, it was a great bike with 28's

cobbwheels · Mar 5, 2023

cyclintom said:
The material is called "prepreg" and it is made out of sheets of carbon fiber impregnated with a type of resin that is cured enough not to be sticky but not completely cured. They stack as many of the prepreg together as necessary for the application put it in the mold and in some cases like wheels, they put a sepa4ration layer or a balloon in between them. They close the mold, inflate the balloon or in some case use high pressure air so push the separate sides of the layers into place and then heat them to a temperature that sets the resins. Never-the-less, there always the possibility of contaminants getting on the surfaces which consequently do not adhere to each other causing a slight separation or "void"

This is where very high tension forces can occur and where cracks in the layup can develop.

Time bicycles fights this by using an additional layer of Vectran which is a man-made thread that is of similar strength to carbon fiber. But whereas carbon fiber is short fiber length, Vectran is long threads. This allows the material to contact a great deal more of the resin and hold the layup together very much longer. While I would trust the best carbon fiber for more than 10 years, Time's method can probably go for 30 years. But MAN are they rigid. My Time could NOT be ridden with 23 mm tires, it was a great bike with 28's

As I imagined it would be.

I was wondering if it is possible to have CF fibers laid across these fiber layers? A 3D CF fiber layup? Never seen anything like it so far except for extremely short CF fibers mixed with epoxy resin but these super short CF fiber plastics are not as stiff and strong as long fiber CF plastics.

A long 3D fiber layup, I'd imagine would be more resistant or even immune to delamination, would last longer, could flex to a greater degree before failure (could tolerate more abuse). But I suppose, it will dramatically change the way we manufacture CF parts and is likely going to make it significantly more expensive. Most likely for example, A whole frame would have to be created with a single mold and the mold would need to have lots of holes to place small bundles of 'z-axis' fibers. I mean seriously, I don't trust the way CF parts are manufactured. On a plane maybe, I'd have less worries because planes are built with much higher safety priorities. While our bikes are usually built to satisfy the whims of weight weenies and UCI nuts. No offense intended!

BrianNystrom · Mar 5, 2023

Tom, you really need to stop adding to this thread, as you have no idea what you're talking about. Starting from the top:

Carbon wheels are made all over the world, not just in China. There are many produced in Europe and here in the US. Not all wheel manufactures have products made in China.

While it's certainly possible that some wheels coming out of China are made in the same molds as brand-name wheels and they could be of the same quality, there is no guarantee of that. They can be made using lower quality materials or simply lower-modulus carbon fiber, which is less expensive. There's simply no way to know for certain what you're getting. That said, I agree that the prices of many brand-name carbon wheels are insane and there are several Chinese companies that are producing quality products that they sell direct to consumers at much lower prices.

The Chinese did not invent the process of making carbon fiber bicycle wheels or other carbon fiber products. Most of the technology came out of the aircraft and aerospace industries, and was adopted by a variety of sports equipment companies. In an effort to reduce costs, many companies moved manufacturing to Taiwan and ultimately to mainland China and brought their technology with them. Early efforts of small Chinese companies to make bicycle rims and other items produced terrible products, but over time they learned from their mistakes (or went out of business) and the quality has improved. The better Chinese manufacturers can produce top-quality products.

Composite technology continues to advance and that includes resin technology. Resins do not "harden over time and get brittle". When they're cured during the manufacturing process, they're as hard as they're ever going to get. Some resins, like epoxies, are prone to damage from UV exposure, so they need to be covered with UV inhibiting clearcoat or an opaque paint to protect them. Epoxies used to join tubes and other components of bike frames are typically inside joints where they're not exposed to UV, so that's largely a non-issue.

Yes, it's possible for voids to occur in composite construction, but the use of either foam cores or pressurized bladders to compress the pre-preg reduces that to a negligible level in properly construction products. I don't know where you get the idea that this process creates "high tension forces", as the prepreg - and woven - layers can move relative to each other until the resin cures. The idea that this is "where cracks in the layup can develop" borders on ludicrous, at least with quality products.

Carbon fiber can be made any length and companies like Time use large spools of it to weave their carbon tubes, instead of using strictly sheets of pre-preg. https://bikerumor.com/video-time-shows-off-their-unique-woven-carbon-fiber-tube-manufacturing/

Vectran is a fiber with very different properties from carbon fiber. For one thing, it has almost zero stiffness; I used to make bowstrings with it and still have a spool or two of it kicking around. It has high tensile strength and it can make a composite tube tougher and more impact resistant, but it won't make it stiffer. If your Time frame was too stiff, it's because the engineers designed it that way and it has nothing to do with the addition of Vectran in the laminate. As for durability, there are thousands of aircraft with carbon fiber-only construction and components that have been flying for decades, much longer than carbon fiber bikes and wheels have been around.

BrianNystrom · Mar 5, 2023

cobbwheels said:
I was wondering if it is possible to have CF fibers laid across these fiber layers? A 3D CF fiber layup? Never seen anything like it so far except for extremely short CF fibers mixed with epoxy resin but these super short CF fiber plastics are not as stiff and strong as long fiber CF plastics.

If you look at the link I posted above, you'll see what I believe is the answer to your question. Carbon fiber fabrics that contain other fiber types are readily available, with carbon/Kevlar being widely used in some products. I don't see it in the bike biz, however.

cobbwheels said:
A long 3D fiber layup, I'd imagine would be more resistant or even immune to delamination, would last longer, could flex to a greater degree before failure (could tolerate more abuse). But I suppose, it will dramatically change the way we manufacture CF parts and is likely going to make it significantly more expensive. Most likely for example, A whole frame would have to be created with a single mold and the mold would need to have lots of holes to place small bundles of 'z-axis' fibers.

The primary benefit of long fibers in composites is the ability to spread stresses over a larger area, thus reducing point stresses that could result in a failure. Delamination is caused primarily by failure of the resin bond due to over-stressing it.

cobbwheels said:
I mean seriously, I don't trust the way CF parts are manufactured. On a plane maybe, I'd have less worries because planes are built with much higher safety priorities. While our bikes are usually built to satisfy the whims of weight weenies and UCI nuts. No offense intended!

To each, his own, but I don't worry about it. I've had carbon fiber bikes for a long time and I have friends who are still riding carbon frames from the '90's. While the failures get all of the headlines and bring carbon haters out of the woodwork, the fact is that quality carbon fiber products work incredibly well and are very durable. Carbon fiber isn't ideal for all applications, but neither is any other material.

More on deep aero carbon tubeless rims.

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