More on deep aero carbon tubeless rims.

Discussion in 'Road Cycling' started by cyclintom, Feb 27, 2019.

  1. cyclintom

    cyclintom Well-Known Member

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    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.
     
    #1 cyclintom, Feb 27, 2019
    Last edited: Feb 27, 2019
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  2. BrianNystrom

    BrianNystrom Member

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    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.
     
  3. cyclintom

    cyclintom Well-Known Member

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    What do you do for a living Brian?
     
  4. BrianNystrom

    BrianNystrom Member

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    Technical writing, instructional design and training. Why?
     
  5. cyclintom

    cyclintom Well-Known Member

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    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.

    Mike's C40 2.JPG
     
  6. BrianNystrom

    BrianNystrom Member

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    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.
     
  7. cyclintom

    cyclintom Well-Known Member

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    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.
     
  8. BrianNystrom

    BrianNystrom Member

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    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.

    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 crap, you apparently didn't learn much from your work experience, or engineering school for that matter.
     
  9. cyclintom

    cyclintom Well-Known Member

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  10. BrianNystrom

    BrianNystrom Member

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

    cyclintom Well-Known Member

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

    BrianNystrom Member

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    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 crap and pretend you know what you're talking about.
     
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