View Poll Results: Are Carbon Wheels Harsh?

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  • Yes

    3 3.30%
  • No

    50 54.95%
  • Yes but don't care, they are friggen AWESOME!

    8 8.79%
  • Yes but I spent too much $$$ I will deny it if asked.

    6 6.59%
  • Can't tell the difference, this is a stupid a$$ poll.

    24 26.37%
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  1. #1
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    Are Carbon Wheels Harsh?

    This has been kinda a hot topic I've been hearing about. For those of you that made the transition from aluminum to carbon wheels do they seem to create a harsh ride being all is equal between wheel builds (except for rims). We are talking vertical compliance.

    Please do your civic duty And vote, comments are somewhat appreciated.

    For those of you that don't like the word harsh it could be translated into
    Harsh=Too stiff radially
    Last edited by bdundee; 09-12-2013 at 07:22 PM.

  2. #2
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    I guess you know how I voted.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  3. #3
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    Quote Originally Posted by meltingfeather View Post
    I guess you know how I voted.
    Perfect, thanks!!

  4. #4
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    Not the best way to ask. Carbon fiber has transformed many sports such as tennis, hockey, bike frames, etc. It DEFINATELY has a damping quality, it absorbs a lot of the harsh shock.....at the same time it is not "noodley" and very stiff. Note, this does not mean harsh ride. It will not flex when cornering and yet absorb many of the harsh hits.....ask anyone that has a carbon fiber frame....

  5. #5
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    Quote Originally Posted by YaMon View Post
    Not the best way to ask. Carbon fiber has transformed many sports such as tennis, hockey, bike frames, etc. It DEFINATELY has a damping quality, it absorbs a lot of the harsh shock.....at the same time it is not "noodley" and very stiff. Note, this does not mean harsh ride. It will not flex when cornering and yet absorb many of the harsh hits.....ask anyone that has a carbon fiber frame....
    Yet you answered it hmmmmm. Recently I heard a Radio show talk about this and he described the carbon wheels as being too harsh of a ride as far as vertical stiffness goes. I.E. your saddle gets jammed up our ars harder on roots with his Envy wheels than his aluminum wheels do. All I want to find out what is other people think.
    Last edited by bdundee; 09-12-2013 at 12:16 PM.

  6. #6
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    With the same spoke tension CF rims don't flex as much as light weight aluminum rims. So all things equal from hub, spoke tension, rim width, tire pressure, then carbon rimed wheels are noticeably stiffer and more harsh.
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  7. #7
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    Quote Originally Posted by bdundee View Post
    Yet you answered it hmmmmm. Recently I heard a Radio show talk about this and he described the carbon wheels as being too harsh of a ride as far as vertical stiffness goes. I.E. your saddle gets jammed up our ars harder on roots with his Envy wheels than his aluminum wheels do. All I want to find out what other people think.
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  8. #8
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    Depends, not the one's you're wearing either.

  9. #9
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    Re: Are Carbon Wheels Harsh?

    If your rims are too "harsh" you have too much air in your tires and you need to get off of the saddle

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  10. #10
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    Quote Originally Posted by bdundee View Post
    Recently I heard a Radio show talk about this and he described the carbon wheels as being too harsh of a ride as far as vertical stiffness goes. I.E. your saddle gets jammed up our arse harder on roots with his Envy wheels than his aluminum wheels do.
    That sounds like a load of crap to me. Talk about all the controlled, back-to-back, on-the-trail "tests" you want, the difference is so incredibly small compared to all the other components of the bike that it's laughable to suggest that, out of a couple of inches of vertical compliance on a hard tail, a rider can tell a difference in rim stiffness of 0.005". Really?
    I'm not sure it is even that much, because all rim stiffness measurements are taken without a tire.
    No doubt different wheels and bikes feel different, which you can't even establish quantitatively, but equating any perceived difference in feel to rim stiffness is just grasping for an explanation.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  11. #11
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    Quote Originally Posted by meltingfeather View Post
    That sounds like a load of crap to me. Talk about all the controlled, back-to-back, on-the-trail "tests" you want, the difference is so incredibly small compared to all the other components of the bike that it's laughable to suggest that, out of a couple of inches of vertical compliance on a hard tail, a rider can tell a difference in rim stiffness of 0.005". Really?
    I'm not sure it is even that much, because all rim stiffness measurements are taken without a tire.
    No doubt different wheels and bikes feel different, which you can't even establish quantitatively, but equating any perceived difference in feel to rim stiffness is just grasping for an explanation.
    Kinda what I thought as well that's why I thought I would ask you Gents.

  12. #12
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    Quote Originally Posted by rho View Post
    If your rims are too "harsh" you have too much air in your tires and you need to get off of the saddle.
    Yep. The air in your tires is going to make a much bigger difference in the harshness of the ride then the actual rims.

  13. #13
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    It wouldn't make as much difference in "harshness" as a 1 PSI change in tire pressure, so, no.

  14. #14
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    Sounds like you've been listening to our musings on Just Riding Along

    In my and my close friends' experiences- which, for all 3 of us includes actually riding both hardtail and FS bikes, back to back, on the same trail, with both carbon and aluminum wheels, with the same tire/tire pressure- Yes, carbon wheels are noticeably more harsh- especially on a hardtail.

    We've had some kickback from a person or two who listens to JRA and doesn't agree with us, so we're planning on doing some slightly more scientific testing that involves weighting a wheel and using a tension meter to actually quantify how much more an aluminum wheel will change shape compared to a carbon one.
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    Quote Originally Posted by Andrea138 View Post
    In my and my close friends' experiences- which, for all 3 of us includes actually riding both hardtail and FS bikes, back to back, on the same trail, with both carbon and aluminum wheels, with the same tire/tire pressure- Yes, carbon wheels are noticeably more harsh- especially on a hardtail.

    We've had some kickback from a person or two who listens to JRA and doesn't agree with us, so we're planning on doing some slightly more scientific testing that involves weighting a wheel and using a tension meter to actually quantify how much more an aluminum wheel will change shape compared to a carbon one.
    People aren't going to believe your results unless you use strain gauges in clinically controlled environments.

  16. #16
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    I think you are wasting your time, and it is a placebo. You should do a blind test (difficult I know with it being on a bike) and see if you can tell the difference between two wheel setups of identical hubs, spokes (# and lacing), rim width, tires, and pressure.

    Carbon wheels should be stiffer than an AL comparison and you should be able to feel that, but harsher? I don't think so.

    If you are hoping for some "give" in your wheels to make your ride more comfortable, then you are doing it wrong.

  17. #17
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    Quote Originally Posted by tooclosetosee View Post
    I think you are wasting your time, and it is a placebo. You should do a blind test (difficult I know with it being on a bike) and see if you can tell the difference between two wheel setups of identical hubs, spokes (# and lacing), rim width, tires, and pressure.

    Carbon wheels should be stiffer than an AL comparison and you should be able to feel that, but harsher? I don't think so.

    If you are hoping for some "give" in your wheels to make your ride more comfortable, then you are doing it wrong.
    There's little point in such a test. What would actually be of value would be to test a known stiff aluminum wheel, such as a Mavic Deemax, a known noodle, like a Stans Crest, and a ENVE carbon wheel.

    Also the hardtail aspect cannot be ignored and I completely agree with your last sentence. There's no doubt that being in the saddle on a hardtail is a rough ride, regardless of wheel. Get out of the saddle on the HT or put the carbon wheels on a full suspension bike and then see if there's any complaints about the stiffness.

  18. #18
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    Are Carbon Wheels Harsh?

    Quote Originally Posted by Andrea138 View Post
    Sounds like you've been listening to our musings on Just Riding Along

    In my and my close friends' experiences- which, for all 3 of us includes actually riding both hardtail and FS bikes, back to back, on the same trail, with both carbon and aluminum wheels, with the same tire/tire pressure- Yes, carbon wheels are noticeably more harsh- especially on a hardtail.

    We've had some kickback from a person or two who listens to JRA and doesn't agree with us, so we're planning on doing some slightly more scientific testing that involves weighting a wheel and using a tension meter to actually quantify how much more an aluminum wheel will change shape compared to a carbon one.
    It's crazy that you guys are the only ones here who actually ride bikes.

    How do you control for confirmation bias in a test that is heavily influenced by your already established opinion and has no real quantifiable scale?

    An impression of how a wheel feels is one thing, and if anybody thinks they can derive value from that more power to them. Tying the feeling to some measurable parameter that hasn't been measured is a leap of faith that defies logic.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  19. #19
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    Are Carbon Wheels Harsh?

    Quote Originally Posted by ColinL View Post
    People aren't going to believe your results unless you use strain gauges in clinically controlled environments.
    No way in hell... They'll say, "how does your lab bench test apply to me on the trail after I've pulled a thick one on a safety break and I'm really feeling it, railing corners and getting playful with it and really throwing my bike around... HUH?!? What then, bra? I actually ride bikes."
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  20. #20
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    I have not back to backed aluminum vs. carbon rims, but my chinese carbon rims feel stiff but not harsh. Seems like an impossible combination, but this is my opinion.

    I do not run super-high spoke tensions (around 100 kgf drive side if I recall correctly), so that may be part of the reason for my opinion. My bike is a Nimble-9, which also probably has a more compliant rear end than a carbon XC race frame.

    I asked Dave from I-9 if he thought an I-9 wheelset with carbon rims would be too stiff / harsh, and he said probably yes. I could see that, since in my experience I-9 aluminum spokes build into a stiffer wheel than steel spokes (again, just my subjective experience).

  21. #21
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    Are Carbon Wheels Harsh?

    Quote Originally Posted by Pslide View Post
    I asked Dave from I-9 if he thought an I-9 wheelset with carbon rims would be too stiff / harsh, and he said probably yes. I could see that, since in my experience I-9 aluminum spokes build into a stiffer wheel than steel spokes (again, just my subjective experience).
    I9 wheels aren't actually that stiff (I've measured them). The low bracing angles caused by their hub design are primarily responsible. The aluminum spokes are also pretty elastic.

    I think this is an obvious example of how the feel is not tied to stiffness. The aluminum construction gives I9 wheels a certain feel, but they aren't stiff like everyone seems to think they are.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  22. #22
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    No difference for me...

    Quote Originally Posted by bdundee View Post
    Yet you answered it hmmmmm. Recently I heard a Radio show talk about this and he described the carbon wheels as being too harsh of a ride as far as vertical stiffness goes. I.E. your saddle gets jammed up our ars harder on roots with his Envy wheels than his aluminum wheels do. All I want to find out what other people think.
    My .02:

    I do not notice additional "harshness" when riding on the carbon rims as compared to aluminum. I run LB Chinese carbon rims, Flows, Crests and 355's. All tubeless at low psi: rears in the low 20's and fronts as low as 18. A reasonably close "apples to apples" comparison of two wheel sets on my FS bike:

    LB carbon rims with DT db spokes (definitely higher tension than the Flows) and Chris King LD front 20mm and 9mm rear.

    Flow rims 2.0 straight DT spokes, Chris King LD front 20mm and 9mm rear).

    I definitely notice additional lateral stiffness when building wheels with carbon rims compared to aluminum though that does not translate into ride "harshness" with LB rims at least...

  23. #23
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    < not sure on the difference between "back to back" and "bare back" can someone asplain plz?

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    I've had a number of different stans rims (355, Flow, Crest), in the past year I've torn down two of my wheelsets and rebuilt the king hubs on LB carbon rims. Nearly all my riding is done on a hardtail and I cannot say that the carbon rims feel any 'harsher'. They're definitely stiffer laterally, and don't need to be trued constantly like the crests/355s. I've raced them all year on a hardtail that is supposed to be super stiff (santa cruz highball) and have only good things to say. Carbon rims were a huge step in the right direction for my mtb riding.

  25. #25
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    Any of you who think we're full o' sh1t over at JRA are welcome to call in and tell us how wrong we are. We're on the air Monday nights from 8-9ish, central time, and the number is (646) 595-4113. We'd also appreciate it if you started other threads on MTBR with links to our show and how much you think we don't know what we're talking about.
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  26. #26
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    Quote Originally Posted by Andrea138 View Post
    We'd also appreciate it if you started other threads on MTBR with links to our show and how much you think we don't know what we're talking about.
    Like... I bet y'all like... would... or something.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  27. #27
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    Preface: I won my set of carbon ENVE AM rims with King hubs so I don't have any monetary bias because I dropped 3k on a set of wheels.

    I actually thought the opposite to be true. I thought the carbon wheels muted trail chatter and obstacles better even with high volume rubber setup tubeless with lower PSI. They're more laterally stiff and respond to side to side changes of direction quicker, but yet seem to be less harsh in the rough. When plowing into a rock I don't feel that harsh clank that you feel with aluminum wheels. And you definitely feel it even with big rubber (think about that unpleasant feeling of hitting a pothole in your car/truck even with big tires on). The carbon rims have more of a muted feel to those hits (more of a dull thud or lack of impact), like it's just your tire hitting it, if that makes any sense. I seem to have less trail vibration translated into my hands and arms even with an aluminum frame and handlebar. Take that for what it's worth. Those are just my trailside completely un-scientific observations. Previous wheels on the same bike were Stan's Flows with DT hubs.

    There's definitely a noticeable increase in performance and they "feel" way better than my aluminum-rimmed wheels and accelerate quicker. Throwing them into corners feels awesome. There's a difference but I definitely don't think it's a $2400 difference. They're not even really much lighter cause I went with the AM rims for durability and a wide tire profile. That being said when I ride my other bikes I do miss them.
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  28. #28
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    Quote Originally Posted by bdundee View Post
    For those of you that don't like the word harsh it could be translated into
    Harsh=Too stiff laterally
    I assume you meant to say too stiff radially, right?

    Well I voted "can't tell a difference" but with that said, I don't think it's a stupid poll. As a carbon rim manufacturer, we get this question all the time, so clearly it's something that people think about when they are buying a set of carbon wheels.

    In short, our research suggests you can't tell a difference in vertical compliance between an aluminum rim and a carbon rim simply because bicycle wheels are not vertically compliant. You don't need to measure anything, there are already vetted papers out there (i.e. Henri Gavin's http://people.duke.edu/~hpgavin/pape...heel-Paper.pdf) which are based on sophisticated modeling techniques that tell us what we need to know: and that is <b>that bike wheels are incredibly stiff radially</b>. Even super-flexy, raceday only aluminum rims are so stiff radially that you can't "feel" vertical deflection due to the wheel/rim bending.

    So with all else equal, are carbon rims more radially stiff than aluminum rims? Yes, they are because carbon as a material has a higher elastic modulus and the rims will have a higher bending moment of inertia in the radial plane. <b>But in the end it doesn't matter, because all wheels are so radially stiff that vertical displacement from any force encountered during normal mountain biking is tiny (i.e. thousandths of an inch). So making the wheel even more radially stiff won't change the way it feels.</b> If you want to see numbers, we show some calculations on our website: Wheel Building Philosophy and Other Info | Nox Composites. Note this page is in DRAFT form and we'd love to get some of you to critique/check our work.

    Now lateral stiffness is a whole different story. A typical wheel is about 50 times less stiff laterally than it is radially! So lateral displacement from normally encountered forces on the trail is something you can feel (and it sucks)... so improving lateral stiffness is one of the primary reasons anyone should want a carbon rim, especially on 29ers and 650b.

    The best way to get more vertical compliance is to run tubeless, drop your air pressure a few psi, user higher TPI tires, or increase your tire volume (either get bigger tires or run wider rims). If all that doesn't help, get suspension :-)

    Brad
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  29. #29
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    Thanks for bringing the science, Brad!

    So, I (and my internet radio friends) have a question, given the info above. Why is it that, for the same bike, tires, tire pressure, shock pressure... blah blah, we all noticed a lot more feedback from small bumps in the trail when riding on carbon wheels? To the point of where, over more than a couple hours' worth of riding, we're feeling more "beaten up" vs. aluminum wheels (That's what we're calling "harsh" and "too stiff" for our liking).

    It's probably worth saying that we're talking about two specific sets of wheels- ENVE 32h XC and ENVE 28h AM, that we've ridden over the past year and a half- independently of each other. We honestly didn't start discussing our past carbon wheel experiences until Matt bought his set just a couple of months ago. All three of us weigh about the same- between 140 and 150 pounds, but have reasonably different riding styles and bike preferences (I'm a hard tail lover, Kenny only rides FS, and Matt has waffled between the two). We're all experienced with proper suspension setup and made small tweaks in shock and tire pressure but always felt like the carbon wheels were a rougher ride than aluminum.

    Given your knowledge, it would be a lot more interesting to talk to you on one of our shows instead of anyone else that's posted here
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  30. #30
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    Quote Originally Posted by Andrea138 View Post
    Any of you who think we're full o' sh1t over at JRA are welcome to call in and tell us how wrong we are. We're on the air Monday nights from 8-9ish, central time, and the number is (646) 595-4113. We'd also appreciate it if you started other threads on MTBR with links to our show and how much you think we don't know what we're talking about.
    spammer...

  31. #31
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    Quote Originally Posted by NoxComposites View Post
    I assume you meant to say too stiff radially, right?



    Brad
    Let's just say I'm not the sharpest tool in the shed when it comes to wheels so I apologize to all for my incorrect use of the proper wording. Heck I usually spend a lot more time riding than writing.


    Oh and thanks for your write up!!

  32. #32
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    Quote Originally Posted by NoxComposites View Post
    I [...]
    Brad
    Dead balls on.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  33. #33
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    Are Carbon Wheels Harsh?

    Quote Originally Posted by Andrea138 View Post
    Thanks for bringing the science, Brad!
    A testament to the fact that delivery trumps content... something I'm working on. Brad said exactly the same thing I did.

    Quote Originally Posted by Andrea138 View Post
    So, I (and my internet radio friends) have a question, given the info above. Why is it that, for the same bike, tires, tire pressure, shock pressure... blah blah, we all noticed a lot more feedback from small bumps in the trail when riding on carbon wheels? To the point of where, over more than a couple hours' worth of riding, we're feeling more "beaten up" vs. aluminum wheels (That's what we're calling "harsh" and "too stiff" for our liking).
    I don't think there is an explanation for a couple of reasons:
    Your impressions based on trail rides are so subject to bias and interpretation as to be impossible to translate into anything scientific or remotely controllable or quantifiable.
    As this thread demonstrates, you three think carbon wheels are "harsher" while others think they "dampen chatter" and yet most others think there is no difference. Your feelings are real, but they may have no explanation or first principles scientific explanation because they are so heavily influenced by a large number of unknown and unquantifiable variables.
    It is easy to turn up astonishing examples of scientific tests that reveal the power of confirmation bias and the general interference of human perception on the distinguishing of verifiable fact.

    The unscientific and uncontrolled nature of your riding experiences does not and can not lead to any conclusions from a scientific perspective, which is something I think a lot of people struggle with.

    My personal and unverifiable theory is that natural frequency plays a much larger role in people's impressions of wheel feel than stiffness. Humans are notoriously poor discerners of small variations in physical dimensions. Google "just-noticeable difference" and the science underlying it for verification of that statement. Humans are, however, fairly keen to small variations in vibration frequency. It is easy to ping two different wheels and pick up the difference in resonant frequency they put out. Try it with the wheels you have. My theory is that this translates into the user experience of wheel feedback, though not in the "beat up" way you describe.

    If you want to put this to the test... ride a couple of laps on your favorite trail that you know well with one of these wheelsets. Then change the tension significantly (say from 100 kgf DS to 70 kgf) and ride it again. My experience is that the wheel feels significantly different, yet the measured stiffness is the same.

    Quote Originally Posted by Andrea138 View Post
    Given your knowledge, it would be a lot more interesting to talk to you on one of our shows instead of anyone else that's posted here
    The not-so-sly dig did not go unappreciated.

    I'd counter with a suggestion to look at the content of posts rather than letting perception/emotions cloud the transmission of data.
    For example, when I said that the statements of "a Radio show" relayed by the OP sounded like a load of crap, I made that determination based on their merit, since until you plugged your show (for the first time) I did not have any idea who had said it and could not have based that comment on how interesting or knowledgeable I think you are.

    The above is some food for thought from an uninteresting (and smart ass ) contributor unqualified for your show.
    Last edited by meltingfeather; 09-12-2013 at 09:35 PM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  34. #34
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    Our collective and totally subjective perception (the just riding along show crew) is in reference to radial "harshness" in the enve carbon wheels we've all ridden. I am comparing back to back with the same tires and pressures on the same bike on the same trail. Everything is 100% identical with the exception of the wheelsets. I'm comparing enve 32h xc factory build with dt aerolite and dt240s hubs to both stans race gold and to american classic hubs on stans crest. In my back to back comparisons I feel the enve wheels are quicker to fatigue me. What does this mean? I feel more feedback which I can only describe as "chatter" at the bars and at the seat and through the pedals. Is this "chatter" a result of increased stiffness both axial and radial? I'm not sure, but it sure seems to be in the radial fashion to me.

    In the end I "feel" the set of enve wheels I rode were stiffer in every way compared to the stans aluminum wheels I ride. Unfortunantly, for me, I think there is noticeable price to pay in the form of increased fatigue. This could be a result of resonate frequencies or some other phenomenon. It may not have anything to do with the measured radial or axial stiffness of the wheels. All I can tell you is what I feel in back to back tests.

    I want to love the enve wheels and all carbon wheels. Light, strong, and reliable. What's not to love? I went into the test assuming my unanimous approval of the carbon enve wheels, only to be surprised by the perceived harshness. Maybe I'm a *****, but I prefer my aluminum wheels for the moment - price not being an issue. Some people may find the enve wheels completely tolerable, I just don't.

    I look forward to a nox composites build I am doing along with the soon to be released stans low spoke count carbon offering.

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    Are Carbon Wheels Harsh?

    Quote Originally Posted by khskenny View Post
    What does this mean? I feel more feedback which I can only describe as "chatter" at the bars and at the seat and through the pedals. Is this "chatter" a result of increased stiffness both axial and radial? I'm not sure, but it sure seems to be in the radial fashion to me.
    Like I said, it doesn't "mean" anything in terms of physical parameters... it is just your subjective opinion, and that's ok (if it's ok with you). Unfortunately it seems like you are trying to attribute your perceptions/opinions to some basis in measurable fact, and the connection is just not there.

    Quote Originally Posted by khskenny View Post
    In the end I "feel" the set of enve wheels I rode were stiffer in every way compared to the stans aluminum wheels I ride. Unfortunately, for me, I think there is noticeable price to pay in the form of increased fatigue. This could be a result of resonate frequencies or some other phenomenon. It may not have anything to do with the measured radial or axial stiffness of the wheels. All I can tell you is what I feel in back to back tests.
    Your feelings are real and valid, but they are limited to significance in your own conscience only... and I guess any radio listeners who might give them credence. As demonstrated, others can ride the same wheels and come to opposite conclusions... doesn't mean either of you is wrong... until you try to expand your opinion into some "meaning" about stiffness in different planes, etc., which transcends the subjective into objective reality, in which opinions are a currency of no value.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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    So, Meltingfeather, if you're willing to put science aside for a second (scary I know), can you tell any discernible difference between carbon wheels you've ridden and aluminum ones on the basis of "harshness" or "chatter" or any other input that you could attribute to fatigue? I'm curious if you've had time on different bracing angles, spoke counts, etc for both rim materials.

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    Are Carbon Wheels Harsh?

    Quote Originally Posted by khskenny View Post
    So, Meltingfeather, if you're willing to put science aside for a second (scary I know), can you tell any discernible difference between carbon wheels you've ridden and aluminum ones on the basis of "harshness" or "chatter" or any other input that you could attribute to fatigue? I'm curious if you've had time on different bracing angles, spoke counts, etc for both rim materials.
    Putting science aside isn't scary because I'm not tied to the idea that my feelings must mean something... at least not anything more than what I need to decide if I like something or not, but I don't have a radio show.
    I rode the same bike (rigid Ti ss), hubs, spokes, tires, pressure, etc. laced to Stan's 355s and then to Nancy Wides... back to back (excluding the 3-hour gap for rebuild time) on my standard Sunday morning two-lap, 20-mile ride, one lap on each set of rims, and I think I felt a bit of a difference a couple of times, but it was hard to say. I did the same thing (with the 355s) only varying spoke tension and I could tell a definite difference. I build wheels both for myself and on a very part time basis for select customers and I've done a number of back-to-back riding tests (not very informative) and many many more wheel measurements (much more informative), mostly out of a personal interest in bikes and a strong tendency toward analytical thinking (I make my living as a licensed professional engineer). I've had pretty extensive training in structural analysis and materials science and studied bike wheels in particular for a good number of years.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

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    What has your analysis of these many informative wheel measurements been telling you?

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    Are Carbon Wheels Harsh?

    Quote Originally Posted by khskenny View Post
    What has your analysis of these many informative wheel measurements been telling you?
    Maybe read my posts?
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

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    Let me be more specific. Does any of your analysis suggest a perceivable difference in "harshness" between wheel building methods and construction (spoke tension, lacing patterns, spoke count, bracing angles, rim material, etc)?

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    Roues Artisanales did a big test with lab data in, and they addressed the vertical compliance issue - no data shows differences between vertical compliance between wheels and the deflection is not perceivable. Lateral defelection is somethign else of course:
    Grand test roues full carbone 2011 ? Partie 3: Rigidité latérale | Roues Artisanales

    I have a set of Giant P-XCR 29er carbon wheels (high 170N tension, 28 spokes), and also 5 other sets of alu 29er wheels I ride on.

    I can tell a difference between alu and carbon, the carbon ones do deflect less - and I was not even sure that was a good thing - I needed to adjust my feeling on the bike - the ride wasn't "harsh", but it did change the way I felt the ground, and for the first few rides - not for the better.

    After a year of racing on them, I have now completely adjusted myself to the new feel.

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    Quote Originally Posted by BaeckerX1 View Post
    Preface: I won my set of carbon ENVE AM rims with King hubs so I don't have any monetary bias because I dropped 3k on a set of wheels.
    ...
    They're not even really much lighter cause I went with the AM rims for durability and a wide tire profile.
    ENVE have stated that there is no durability difference between their XC and AM wheels; they are built using the exact same construction techniques, layup schedules, and materials, to include wall thicknesses. The only difference is width. That's it.
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    Are Carbon Wheels Harsh?

    Thanks goran. It's really interesting to me that test data shows little difference in radial deflection, yet different wheel sets have completely different ride qualities. Can humans perceive the minuscule difference in radial deflection or maybe only when the difference is repeated 10,000 times over a long ride? Or is there another harder to test for dynamic phenomenon at work?

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    Just a clarification on my statement, I didn't say that my carbon deflects less (vertically or radially).

    It did deflect less laterally (or that is my feel of the sensation), feeling is similar to not "giving up" on e.g a camber root but forcing the picked (mini) line. Again, that sensation is not something I acknowledged as a positive change right away, partly because I did not pay 2000+ dollars for the set :-).

    With rides I learned to appreciate the different feel and what tires play well (for me) with the carbon rims to give me the feel I wanted.

    What I can say is that the carbon wheels did survive some of my mistakes, very very similar to the one that tacoed a i19 wheel before.

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    I'd be interested in seeing the results of a "blind" test. If the JRA crew could somehow duct tape or mask both rims so you couldn't tell them apart and wear earplugs so you couldn't hear the difference between them it would be a more unbiased test. Pre conceived notions can sometimes alter reality.

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    Quote Originally Posted by Andrea138 View Post
    It's probably worth saying that we're talking about two specific sets of wheels- ENVE 32h XC and ENVE 28h AM, that we've ridden over the past year and a half- independently of each other.
    Andrea, you've probably already thought of this, but I thought I'd point out that these two rims have ~6mm of difference in internal width. I'd expect the AM rim to be much more comfortable with all else equal (same tires, etc.) because of the additional tire volume, do your experiences concur? This is one (of many) reasons to go wide. And why our XC rims are 23mm and AM rims are 27mm internal width.

    Also, if you guys are comparing a crest or race gold rim (21mm) to an Enve XC (18mm) then you are giving up ~15% in width which is translating to reduced tire volume and less vertical compliance from the tire.

    Funny side story: A training partner had a high-end FS bike that he always thought felt harsh, especially when compared to my bike with almost the exact same wheels/suspension design. After upgrading bearings, sending his shock to Push and playing around with suspension settings for weeks, he finally realized that his and my pump gauge were way off from each other, so although we thought we had the same pressure, his was about 8psi higher. After dropping 8psi his problems were fixed. I can even tell the difference between two tire casings, like a Maxxis EXO versus one without sidewall protection.

    Tire compliance is incredibly important in this feeling of getting "beat up." My guess is that all your perceptions are real, but somehow tied to variation in rim width, which ultimately is changing the volume of your tires.

    Quote Originally Posted by Andrea138 View Post
    Given your knowledge, it would be a lot more interesting to talk to you on one of our shows instead of anyone else that's posted here
    Well I'm no expert, just motivated to learn what's going on to help customers get the best wheel build possible. But I'd be willing to chat with you guys. I listened to the show in question. If you are still planning to be in Knoxville soon, let's go for a ride!

    Brad
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    I had the set of ENVE XC wheels that I rode for a season. During that time, Kenny also rode them a good bit (he's khskenny in this thread). Matt just purchased his wheels- the ENVE AMs, a couple of months ago, and his comparison (which isn't here, but I'm sure you've heard on the show) is against some Hope/Stan's Arch wheels. I haven't ridden Matt's AM wheels, but from talking to him, it sounds like he's had the same experience as Kenny and I.

    I went from the ENVEs to I9 Trail 24 wheels, which are definitely wider. So, now that you mention it, I think the next step would be to put my tires on Matt's ENVE AM wheels and go for a ride! As far as pump accuracy, I always use the same pumps, so if they are wrong, they should be "reliably" wrong. I can't speak for Matt & Kenny, but I definitely did quite a bit of pressure tweaking when I was riding the ENVE wheels.

    I'm going to be in Knoxville for the TN Adventure Challenge adventure race on October 12th. Keep in touch and we can grab a beer.
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    Are Carbon Wheels Harsh?

    Great discussion so far. Brad, you have a very valid point. In my comparison there was indeed a few mm internal width difference and tire volume was something that came to mind in my test ride. I ended up dropping from my usual 26 psi on a maxxis ikon 2.2 exo non tubeless down to 24psi and lower on the narrower enve. The reduced pressure resulted in slightly less harshness, but I noticed more tire sidewall deflection at the reduced pressure. I would definitely argue that in my experience so far wider rims have been better in terms of tire volume and reduced sidewall squirm.

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    Are Carbon Wheels Harsh?

    Quote Originally Posted by khskenny View Post
    It's really interesting to me that test data shows little difference in radial deflection, yet different wheel sets have completely different ride qualities.
    This is also extraordinarily interesting to me and something I've spent a lot of time thinking about, talking about, and studying.
    Quote Originally Posted by khskenny View Post
    Can humans perceive the minuscule difference in radial deflection or maybe only when the difference is repeated 10,000 times over a long ride?
    I don't think so and the relevant science doesn't suggest that we can. However, JND tests are typically not repeated 10,000 times in a row. That's an interesting point, though don't you say that you can pick up the differences immediately, not just after the ride is over and you notice you are more or less tired?

    Quote Originally Posted by khskenny View Post
    Or is there another harder to test for dynamic phenomenon at work?
    This is what I think.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

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    Are Carbon Wheels Harsh?

    Quote Originally Posted by khskenny View Post
    Let me be more specific. Does any of your analysis suggest a perceivable difference in "harshness" between wheel building methods and construction (spoke tension, lacing patterns, spoke count, bracing angles, rim material, etc)?
    No analysis or measurement could suggest "harshness" unless you defined that term in some independently measurable way, which gets back to the origin of this conversation. If you wanted it to be scientific, you would have to use the standardized and accepted definition of harshness, and since there isn't one, make one up and lay it out in terms that a scientist could interpret without your input.
    I've picked up differences riding... don't know that I'd call it "harshness." I know I wouldn't characterize any of the feelings I've gotten as contributing to fatigue, but maybe I'm not thinking about it in the same way you are. That's kind of the difficulty of impression, especially when I don't know you. If we'd been riding buddies for years and traded bikes and beers and such I'd have a much better idea where you're coming from/what you mean by "harshness."
    Last edited by meltingfeather; 09-13-2013 at 01:12 PM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

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