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  1. #1
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    Sapim CX-Ray or DT Aerolite

    Hello

    I am looking for spokes for my new set of wheels. I'll be riding Notubes Crest rims with Tune King hubs.
    Any specific appreciation, recommendation, like or dislike for the Sapim CX-Ray or DT Aerolite spokes??

    Best to all...

  2. #2
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    Quote Originally Posted by hmpoliveira
    Hello

    I am looking for spokes for my new set of wheels. I'll be riding Notubes Crest rims with Tune King hubs.
    Any specific appreciation, recommendation, like or dislike for the Sapim CX-Ray or DT Aerolite spokes??

    Best to all...
    Love the CX-Rays.

    Will not use the rims.
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    Quote Originally Posted by shiggy
    Love the CX-Rays.

    Will not use the rims.
    Why would you not use the rims? Any bad experience?

  4. #4
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    Quote Originally Posted by hmpoliveira
    Why would you not use the rims? Any bad experience?
    Too low of a spoke tension limit and I feel the design overstresses the tire bead in a manner the tires are not designed to be used.
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    Quote Originally Posted by shiggy
    Too low of a spoke tension limit and I feel the design overstresses the tire bead in a manner the tires are not designed to be used.

    Which rim would be a better option then?? Have you got any expirience with Aerolite spokes??

  6. #6
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    I love my Crest rims, so far...

  7. #7
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by hmpoliveira
    Which rim would be a better option then?? Have you got any expirience with Aerolite spokes??
    I prefer something like the BOnty Race Lite TLR (true tubeless).

    Have not used the DTs but the spec is identical to the CX-Ray and I have never had an issue with DT spokes (or Sapim).
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  8. #8
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    Quote Originally Posted by shiggy
    I prefer something like the BOnty Race Lite TLR (true tubeless).

    Have not used the DTs but the spec is identical to the CX-Ray and I have never had an issue with DT spokes (or Sapim).

    Those rims can not be sold separately (at least in Europe)
    Thanks for your great help so far...

  9. #9
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    just built myself some cx-rays/crest29/Hope, couldn't be happier. But yes, these rims don't like these spokes.

  10. #10
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    Quote Originally Posted by banksd1983
    just built myself some cx-rays/crest29/Hope, couldn't be happier. But yes, these rims don't like these spokes.

    Why you say that??

  11. #11
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    Quote Originally Posted by hmpoliveira
    Why you say that??
    he must be joking. spokes don't have opinions of other components.
    there is nothing about a bladed spoke that makes it incompatible with any rim.

    OP - aerolites & CX Rays are like in weight, geometry, and quality. I can't think of anything to recommend one over the other. Revolutions & Lasers belong to that group and cost a fraction of their bladed cousins.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  12. #12
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    yeah, that got worded incorrectly. Shiggy touched on it earlier, and Notubes mentions it on their forum, the lower "recommended" spoke tension on their rims is 95-100kgf, whereas cx-rays typically build better at higher numbers. That's just what they say though.

  13. #13
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    Quote Originally Posted by banksd1983
    yeah, that got worded incorrectly. Shiggy touched on it earlier, and Notubes mentions it on their forum, the lower "recommended" spoke tension on their rims is 95-100kgf, whereas cx-rays typically build better at higher numbers. That's just what they say though.
    what does "build better" mean and why is that?
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  14. #14
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    More tension = wheel flexes less and holds its true better. But not so good if it means the spoke nipples deform or crack the rim wall and cause the rim to fail. Less tension can be okay if you use more (and thinner) spokes (since less likely to be detensioned), and if you look at the Stan's wheel specs they often use 32 1.8x1.5x1.8mm spokes.

    Bottom line is that more spokes and more tension gives a stronger wheel if the rim is up to it, but it's okay to have a "strong enough" wheel that's up to your use and save some weight by reducing the safety margin by a reasonable amount.

    What's strong enough will depend on your weight and riding style, and conditions where you ride, so it's hard to make solid recommendations for others.

  15. #15
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    Quote Originally Posted by satanas
    More tension = wheel flexes less
    Not true. Tension does not affect stiffness (flex). Read Question #1 here.
    Quote Originally Posted by satanas
    Bottom line is that more spokes and more tension gives a stronger wheel if the rim is up to it, but it's okay to have a "strong enough" wheel that's up to your use and save some weight by reducing the safety margin by a reasonable amount.
    wise words.
    Quote Originally Posted by satanas
    What's strong enough will depend on your weight and riding style, and conditions where you ride, so it's hard to make solid recommendations for others.
    more of same.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  16. #16
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    Not trying to stir up any *****, but this is what DT and Sapim have to say on the subject:

    Sapim Email:
    Hello, I am considering CX-Spokes for a wheel using a Stans Arch rim. This rim has a maximum spoke tension of 1000N. I've been told that CX-Ray spokes need to be built to much higher spoke tension (1200N+) in order to function properly.

    Can you confirm or deny this?

    Will I have any problems with CX-Rays tensioned at 1000N?


    Yes indeed, the best way to assemble a wheel with cx-ray spokes is to work with higher tensions. Tensions of + 130 kg on the gear side of the rear wheel and + 120 kg on the disc side of the front wheel or + 100 kg for a race wheel or MTB without disc.

    The lifetime of the spoke will decrease if you use tensions below the advised ones. Also the stability of the wheel will not be that good. It has everything to do with the high elasticity of the spokes.

    I would not recommend to use cx-ray spokes on a rear wheel with tensions below the 130 kg ( on the gear side).

    1000 N spoke tension on the rim. Are you sure that the rim can’t hold more? This means that the rims is not a strong rim. We often see this kind of strengths on single walled city rims. Double walled aluminum rims are in general perfect to use with these higher tensions. Softest alu rims are limited to 120 kg. The higher qualities often from 120 up to 150 kg. The very good ones even more.

    Best regards

    Wim


    DT Email:
    Hello, I am considering Aerolite spokes for a wheel using a Stans Arch rim. This rim has a maximum spoke tension of 1000N. I've been told that Aerolite spokes need to be built to much higher spoke tension (1200N+) in order to function properly. Can you confirm or deny this? Will I have any problems with Aerolites tensioned at 1000N? Thank you for time

    Hello

    First of all thank you for your interest in our products.

    Regarding your question I can confirm you E-Mail. The spoke tension on wheels build with aerolite spokes should be higher.

    When you will build a wheel with less tension the stability will not be high enough when riding corners as the lateral stiffness of a bladed spoke will be less then at a round spoke.
    Have a nice day and enjoy riding your bike.

    Freundliche Grüsse / Regards / Salutations
    Friso Lorscheider
    Int. Service & Race Support Manager
    DT Swiss AG
    Last edited by jager7; 08-26-2010 at 03:26 PM.

  17. #17
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    Quote Originally Posted by jager7
    Not trying to stir up any *****, but this is what DT and Sapim have to say on the subject:
    No ***** stirring attempts perceived. Asking questions of knowledgeable people is a way to get answers. What's shocking to me is that representatives of reputable spoke manufacturing companies could have such misunderstandings of wheel systems. It's no wonder this misinformation trickles down to shops and consumers. These service and/or technical support reps likely have not had any formal training on the subject, but there must be people at DT and Sapim that know what these people are saying is wrong, and IMO they should have the basics down. I'll point out what is clearly wrong.
    Quote Originally Posted by jager7
    Sapim Email:
    Hello, I am considering CX-Spokes for a wheel using a Stans Arch rim. This rim has a maximum spoke tension of 1000N. I've been told that CX-Ray spokes need to be built to much higher spoke tension (1200N+) in order to function properly.

    Can you confirm or deny this?

    Will I have any problems with CX-Rays tensioned at 1000N?


    Yes indeed, the best way to assemble a wheel with cx-ray spokes is to work with higher tensions. Tensions of + 130 kg on the gear side of the rear wheel and + 120 kg on the disc side of the front wheel or + 100 kg for a race wheel or MTB without disc.

    The lifetime of the spoke will decrease if you use tensions below the advised ones. Also the stability of the wheel will not be that good. It has everything to do with the high elasticity of the spokes.

    Highly elastic spokes (which CX Rays and Aerolites are due to their low cross-sectional area) tolerate lower spoke tension better than thicker spokes. At a given build tension, an elastic spoke will have stretched further, meaning that when the rim deflects due to load, the spoke can absorb that deflection without going slack to a greater extent than a thick spoke, which will not have stretched as far. The increased ability to absord deflection also translates into better load sharing between adjacent spokes.
    Why would you go with lower tension for a race wheel? Why is lower tension acceptable on a non-disc wheel? Nonsensical & conflicting information.
    Quote Originally Posted by jager7
    I would not recommend to use cx-ray spokes on a rear wheel with tensions below the 130 kg ( on the gear side).

    I guess what he's saying is that you need to choose your rim based on your spokes, which is backward from how most people do it. What he's also saying is that no rim from Mavic or Stan can be used to build 3X wheels and that American Classic, in offering wheelsets with CX Rays at tension below the Sapim suggestion, builds wheels with poor stability.
    *edit* No DT Swiss mtb rims either
    Quote Originally Posted by jager7
    1000 N spoke tension on the rim. Are you sure that the rim can’t hold more? This means that the rims is not a strong rim. We often see this kind of strengths on single walled city rims. Double walled aluminum rims are in general perfect to use with these higher tensions. Softest alu rims are limited to 120 kg. The higher qualities often from 120 up to 150 kg. The very good ones even more.
    I'd like to know how many "very good" rims there are with max tension specs above 150 kgf. There is no reason to build wheels that tight for disc-braked mountain bikes. 12 spoke road wheels? Maybe, but I don't mess with those.
    It's a shame.
    Quote Originally Posted by jager7
    DT Email:
    Hello, I am considering Aerolite spokes for a wheel using a Stans Arch rim. This rim has a maximum spoke tension of 1000N. I've been told that Aerolite spokes need to be built to much higher spoke tension (1200N+) in order to function properly. Can you confirm or deny this? Will I have any problems with Aerolites tensioned at 1000N? Thank you for time

    Hello

    First of all thank you for your interest in our products.

    Regarding your question I can confirm you E-Mail. The spoke tension on wheels build with aerolite spokes should be higher.

    Same point about elastic spokes tolerating lower tension better.
    Quote Originally Posted by jager7
    When you will build a wheel with less tension the stability will not be high enough when riding corners as the lateral stiffness of a bladed spoke will be less then at a round spoke. Have a nice day and enjoy riding your bike.
    He didn't even answer your question, but still managed to provide misinformation. I've heard this one about spoke shape and lateral stiffness before, and to be honest, it's laughable. The shape of the spoke has no effect on lateral stiffness. What matters is the spoke's elasticity, which is independent of shape, obviously.
    It's unfortunate that a consumer can't get reliable information from the manufacturers of the products he intends to use. I can't be surprised when people regurgitate misinformation that they're getting straight from the source.
    Last edited by meltingfeather; 08-26-2010 at 09:01 AM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  18. #18
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    Quote Originally Posted by meltingfeather
    No ***** stirring attempts percieved. Asking questions of knowledgeable people is a way to get answers. What's shocking to me is that representatives of reputable spoke manufacturing companies could have such misunderstandings of wheel systems. It's no wonder this misinformation trickles down to shops and consumers. These service and/or technical support reps likely have not had any formal training on the subject, but there must be people at DT and Sapim that know what these people are saying is wrong, and IMO they should have the basics down. I'll point out what is clearly wrong.
    [/color]
    Highly elastic spokes (which CX Rays and Aerolites are due to their low cross-sectional area) tolerate lower spoke tension better than thicker spokes. At a given build tension, an elastic spoke will have stretched further, meaning that when the rim deflects due to load, the spoke can absorb that deflection without going slack to a greater extent than a thick spoke, which will not have stretched as far. The increased ability to absord deflection also translates into better load sharing between adjacent spokes.
    [/color]
    I guess what he's saying is that you need to choose your rim based on your spokes, which is backward from how most people do it. What he's also saying is that no rim from Mavic or Stan can be used to build 3X wheels and that American Classic, in offering wheelsets with CX Rays at tension below the Sapim suggestion, builds wheels with poor stability.

    I'd like to know how many "very good" rims there are with max tension specs above 150 kgf. There is no reason to build wheels that tight for disc-braked mountain bikes. 12 spoke road wheels? Maybe, but I don't mess with those.
    It's a shame.
    [/color]
    Same point about elastic spokes tolerating lower tension better.

    He didn't even answer your question, but still managed to provide misinformation. I've heard this one about spoke shape and lateral stiffness before, and to be honest, it's laughable. The shape of the spoke has no effect on lateral stiffness. What matters is the spoke's elasticity, which is independent of shape, obviously.
    It's unfortunate that a consumer can't get reliable information from the manufacturers of the products he intends to use. I can't be surprised when people regurgitate misinformation that they're getting straight from the source.

    oh men... I'm lost!!!!!

    In the messageboard.notubes.com there are many people advising to take lasers instead of CX Ray for the ZTR Crest.

    Meltingfeather, you seemed to be very well informed For an AM bike, rider of 60 Kg, which spokes would you recommend for my Crest rims?? (knowing that should be the other way around )

    Best

  19. #19
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    Quote Originally Posted by hmpoliveira
    oh men... I'm lost!!!!!

    In the messageboard.notubes.com there are many people advising to take lasers instead of CX Ray for the ZTR Crest.

    Meltingfeather, you seemed to be very well informed For an AM bike, rider of 60 Kg, which spokes would you recommend for my Crest rims?? (knowing that should be the other way around )

    Best
    choosing spokes for your rims is a great way to go about it. I probably wouldn't use Crests for an AM bike, so it's hard to say. Lasers/Revos provide the same weight and performance as CX Rays/Aerolites at a fraction of the cost. An elastic spoke is a good match for a lightweight rim, for the reasons described. I use Revos for all of my builds with Crests.
    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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    Quote Originally Posted by meltingfeather
    choosing spokes for your rims is a great way to go about it. I probably wouldn't use Crests for an AM bike, so it's hard to say. Lasers/Revos provide the same weight and performance as CX Rays/Aerolites at a fraction of the cost. An elastic spoke is a good match for a lightweight rim, for the reasons described. I use Revos for all of my builds with Crests.

    Thanks man

    Since I am quite lighty (like everybody says) I assume the Crest will be OK.

  21. #21
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    jager7, you might want to remove the email address from that post of yours unless you want the guy to receive obscene amounts of spam.

  22. #22
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    Quote Originally Posted by dropadrop
    jager7, you might want to remove the email address from that post of yours unless you want the guy to receive obscene amounts of spam.
    x2, that's why I pulled it from the quote.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  23. #23
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    Quote Originally Posted by dropadrop
    jager7, you might want to remove the email address from that post of yours unless you want the guy to receive obscene amounts of spam.
    Thanks for the heads up, I was smart enough to not add the headers for that very reason, but not smart enough to notice the email address at the bottom.

  24. #24
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    i emailed notubes and asked about recommended spoke tension on their crest since it wasn't listed on their web page. also asked a question about their "low-ish" spoke tension. response:


    95 to 100 kilo
    These are not low tensions.


    wonder if they get that a lot.

  25. #25
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    Question for meltingfeather: Do you use the 2.0/1.7/2.0mm Revos or the 1.8/1.5/1.8mm ones for the Stans rims? Thanks.

  26. #26
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    Quote Originally Posted by minh
    wonder if they get that a lot.
    I'm guessing that they do, since that myth seems to be persistent, despite it being very easy to ask and/or look up other rim mfr specs and find that stan's specs are right about average.
    i'm baffled at how this crap seems to float around for so long when 5-10 minutes of looking will put it to bed.
    Last edited by meltingfeather; 08-26-2010 at 07:50 PM.
    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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    Quote Originally Posted by satanas
    Question for meltingfeather: Do you use the 2.0/1.7/2.0mm Revos or the 1.8/1.5/1.8mm ones for the Stans rims? Thanks.
    Revos come in 2.0/1.5 and 1.8/1.5.
    I use the 2.0/1.5 version because they're easier to get, hubs are designed around 2.0 spokes (the tighter the fit at the hub, the better), and I've never been a big fan of 1.8 at the nipple end. I don't have anything other than my experience to back up that last reason, but I've replaced S.Comps (1.8 at the threads) broken at the nipple probably 10:1 over any other spoke. This is in wheels I didn't build because I'm not a fan of S.Comps for the same reason.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  28. #28
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    For what its worth, I have a singlespeed "race" wheelset using 2.0/1.5 revos laced to Stans 355 rims. These wheels flex a lot. If I have a hard landing that isn't clean, The wheel whips all over the place - Luckily it whips right back into shape. I've had my tire run the frame because of awkward landings. This doesnt happen with other wheelsets that I ride.

    I've just had a rear wheel built using CX-Rays and a Crest rim. I'm anxious to try it out and see how that wheel rides.

    I'm riding 29ers only.

  29. #29
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    Thanks for that meltingfeather!

    FWIW, I still have a pair of wheels built in 1992 with 1.8/1.6/1.8 DT DB spokes, with zero breakages so far. I'm inclined to think that 1.8mm at the nipple isn't a bad idea as it makes the nipple wall a bit thicker, and thus (hopefully) a bit harder to round out if alloy. In practice, 1.8 at the hub end doesn't seem to be a problem if enough tension, despite not being as good a fit as 2.0. I haven't built any lightweight disc wheels with 1.8mm spokes though, so my experience may be irrelevant.

  30. #30
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    Quote Originally Posted by satanas
    Thanks for that meltingfeather!

    FWIW, I still have a pair of wheels built in 1992 with 1.8/1.6/1.8 DT DB spokes, with zero breakages so far. I'm inclined to think that 1.8mm at the nipple isn't a bad idea as it makes the nipple wall a bit thicker, and thus (hopefully) a bit harder to round out if alloy. In practice, 1.8 at the hub end doesn't seem to be a problem if enough tension, despite not being as good a fit as 2.0. I haven't built any lightweight disc wheels with 1.8mm spokes though, so my experience may be irrelevant.
    Yeah, there's no real reason other than my experience for the preference, and I recognize that my experience is pretty worthless in the grand scheme. The trade-off for thicker nipple walls is smaller threads... just something to consider.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  31. #31
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    I'll be tracking this because I lost another Sapim CX-ray laced to my 29er ZTR355.

    Under my guidance, riding agressively on a hardtail at 165lbs, I keep braking these spokes...but only in loose rock conditions. I believe that the rocks are coming up and hitting the spokes in the midsection and causing the failure. Very disappointing because other than this, the wheels stay true over 5 years of riding (different rims, same brand of spoke). NOW, I did not build the wheel so cannot attest to the tension. Maybe I'll check with the wheelbuilder.

  32. #32
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    Quote Originally Posted by Cannonhead
    I'll be tracking this because I lost another Sapim CX-ray laced to my 29er ZTR355.

    Under my guidance, riding agressively on a hardtail at 165lbs, I keep braking these spokes...but only in loose rock conditions. I believe that the rocks are coming up and hitting the spokes in the midsection and causing the failure. Very disappointing because other than this, the wheels stay true over 5 years of riding (different rims, same brand of spoke). NOW, I did not build the wheel so cannot attest to the tension. Maybe I'll check with the wheelbuilder.
    This is an interesting experience. In and of itself it doesn't mean that the following is broadly applicable, but it is consistent with some at least theoretical reasoning why bladed spokes are in fact not a good choice for mtb applications. The reasoning being that the forging process makes them more brittle, so more susceptible to impact damage, and that the increased surface area of the blade increases the chances of impacts. I'd be interested in what your wheelbuilder says.
    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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    FWIW I also have been building my own wheels and have built them professionally as well for almost 40 years. I have very much liked the CX-Rays but make sure you build with plenty of spoke lube in there because if those nipples start to bind on the threads, it's a total pain in the a$$. Like the last poster, I have never broken a CX-Ray in normal riding but have had them break after being hit hard with a rock.

    I "feel" that the CX-Rays build up a stiffer wheel than the Revos (2.0/1.5s). Since they have the same material gauges I have to believe Sapim's literature that it is a material difference between them. Never broke a Revo either....

  34. #34
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    Quote Originally Posted by davek
    Like the last poster, I have never broken a CX-Ray in normal riding but have had them break after being hit hard with a rock.
    Also interesting... and follows from the increased brittleness & surface area of Rays over like-gauged round spokes.
    Quote Originally Posted by davek
    I "feel" that the CX-Rays build up a stiffer wheel than the Revos (2.0/1.5s). Since they have the same material gauges I have to believe Sapim's literature that it is a material difference between them. Never broke a Revo either....
    A CX-Ray starts out as a Laser and is forged a second time to get the bladed shape. The forging does change some properties, but elasticity is not one of them.
    I've found that wheels can feel different even when they have the same stiffness, so it may be that what you're interpreting as stiffness isn't stiffness but something else, like natural frequency.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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    possibly

    it's possible, but i was expecting the sapims to be a bit flexy based on the description of their properties and i didn't find them to be so. you are right that they were very different applications (sapims in a 29er wheelsets vs revos in 26ers) but if anything i'd have expected the 26ers to feel quite a bit stiffer because of the smaller diameter.

    i do differ with one comment you made earlier that the shape of the spoke does not affect the lateral stiffness of the wheel. i do agree that spoke tension is the most important factor in that. but, a round cross section will have a larger bending moment compared to a bladed section of the same gauge. if the rim is trying to move laterally to the hub, as it will when pushing a wheel hard into a corner, the additive effect of greater bending moment of round spokes should contribute at some level to lateral stiffness of the wheel. i concur with whichever spoke manufacturer made that statement above.

  36. #36
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    Quote Originally Posted by meltingfeather
    The shape of the spoke has no effect on lateral stiffness.
    you couldn't be more wrong, ever heard of the radius of gyration? maybe you better look
    it up and will see why a bladed spoke will flex more. a balded spoke will buckle(flex) sooner than a round one even if the x sectional areas are the same.

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    you're right for sure

    i totally agree, see my post at the very end of the thread from just a few minutes ago. i also think the whole question of material composition as it applies to strength characteristics has been missing from the discussion. it's been a while since i studied up on Revos vs Sapims but it seems like i recall they are quite different materials and, if so, one would expect them to have different characteristics.

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    a revo is the same spoke as an aerolite, the latter is just forged into the bladed shape
    which is why the added cost. it is that forging process which adds strength to the aerolite
    and why dt swiss says you can use aerolites but not revos for disc brake wheels.

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    oh, and i noticed you don't think forging would change the elasticity. i question that as well. if they are cold forged, which would add strength, that strength would by definition come at the cost of elasticity. greater strength results in more brittle and less elastic material - all other things being equal of course!

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    Quote Originally Posted by davek
    it's possible, but i was expecting the sapims to be a bit flexy based on the description of their properties and i didn't find them to be so. you are right that they were very different applications (sapims in a 29er wheelsets vs revos in 26ers) but if anything i'd have expected the 26ers to feel quite a bit stiffer because of the smaller diameter.
    my point was that unless you measured the wheels, you don't know which one was stiffer. perceptions of riding can be misleading.
    Quote Originally Posted by davek
    i do differ with one comment you made earlier that the shape of the spoke does not affect the lateral stiffness of the wheel. i do agree that spoke tension is the most important factor in that. but, a round cross section will have a larger bending moment compared to a bladed section of the same gauge. if the rim is trying to move laterally to the hub, as it will when pushing a wheel hard into a corner, the additive effect of greater bending moment of round spokes should contribute at some level to lateral stiffness of the wheel. i concur with whichever spoke manufacturer made that statement above.
    bending moments in no way factor into the structural behavior of simply loaded tension members.
    I said spoke tension does not affect lateral stiffness, and it doesn't, so you must be referring to someone else's comment on that.
    Last edited by meltingfeather; 01-23-2011 at 06:03 PM.
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    that is true of course but spokes are not simply tension members. tension occurs for those loads along the axis of the wheel - those include weight bearing, and acceleration forces. any situation that sideloads the rim relative to the hub (any cornering will do this) is a transverse load that places the spokes under bending stress. surely you recognize that a wheel being forced hard around the corner is trying to fold on itself? if it weren't for those forces, you could get away with a single set of spokes that went from the center of the hub up to the rim. you need the two sets - one on each side of the hub - to provide lateral stability for cornering.

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    Quote Originally Posted by meltingfeather

    bending moments in no way factor into the structural behavior of simply loaded tension members.
    that is true when a wheel is at rest.

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    Quote Originally Posted by peabody
    that is true when a wheel is at rest.
    it is true as long as the spokes are in tension.
    Quote Originally Posted by pvd
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    Quote Originally Posted by davek
    oh, and i noticed you don't think forging would change the elasticity. i question that as well. if they are cold forged, which would add strength, that strength would by definition come at the cost of elasticity. greater strength results in more brittle and less elastic material - all other things being equal of course!
    question all you like. ask a metallurgist or materials testing engineer.
    i TA'd materials lab in grad school and have seen the results myself, as well as having studied the structural performance of steel and specifically with regard to cold forging.
    elasticity is an atomic-level phenomenon. cold forging changes the grain structure, which is many orders of magnitude above atomic-level.
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    Quote Originally Posted by peabody
    you couldn't be more wrong, ever heard of the radius of gyration? maybe you better look
    it up and will see why a bladed spoke will flex more. a balded spoke will buckle(flex) sooner than a round one even if the x sectional areas are the same.
    uh... buckling happens in compression. skim the basics, will ya? it's hard not to be a smart ass when you're talking radius of gyration and buckling in regards to a wire in tension. just how do you buckle a wire by pulling on it?
    Quote Originally Posted by pvd
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    Quote Originally Posted by davek
    i totally agree, see my post at the very end of the thread from just a few minutes ago. i also think the whole question of material composition as it applies to strength characteristics has been missing from the discussion. it's been a while since i studied up on Revos vs Sapims but it seems like i recall they are quite different materials and, if so, one would expect them to have different characteristics.
    they are both stainless steel. if you like, you can compare lasers and CX-Rays, as they are the exact same stainless steel. just sub "laser" every time i've said "revo"
    Quote Originally Posted by pvd
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    well congrats on that TA-ship, all i did was get a m.s. in materials science. been a while (1985) so maybe materials don't behave like they used to, i know mine don't!

    seriously, forging strengthens metals because it introduces strain dislocations in the grain structure, and then locks them in place. because the dislocations impede the sliding of layers within the crystal lattice, that makes the material stronger (resists deformation) but more brittle. how are you defining elasticity? a strong material is indeed very elastic in that as long as it is strained below it's yield strength it will snap back to its original shape - that is elasticity. but i think you are confusing elasticity with strain before breaking, which is higher is weaker materials.

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    Quote Originally Posted by davek
    well congrats on that TA-ship, all i did was get a m.s. in materials science. been a while (1985) so maybe materials don't behave like they used to, i know mine don't!
    If you got an MS in materials science why do you think bending moments apply to wire in tension?
    Quote Originally Posted by davek
    seriously, forging strengthens metals because it introduces strain dislocations in the grain structure, and then locks them in place. because the dislocations impede the sliding of layers within the crystal lattice, that makes the material stronger (resists deformation) but more brittle. how are you defining elasticity? a strong material is indeed very elastic in that as long as it is strained below it's yield strength it will snap back to its original shape - that is elasticity. but i think you are confusing elasticity with strain before breaking, which is higher is weaker materials.
    elasticity is defined exactly as it was when you got your MS... and it is as unaffected by cold forging as it was when the egyptians worked out some of the basics a few thousand years ago.
    i don't think i should have to point this out, but dislocations impeding sliding between layers in the crystal lattice applies to plastic deformation, not elastic deformation... remember?
    how did you get an MS in materials science without understanding the difference between elastic and plastic deformation and the mechanisms behind them, or has it just been too long?

    i don't mean to be frank/blunt/rude, but you guys pulling out some technical terms and telling me i should look stuff up while completely missing the very basics of the application is... hmmm... i'm at a loss.
    Quote Originally Posted by pvd
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    Quote Originally Posted by davek
    that is true of course but spokes are not simply tension members. tension occurs for those loads along the axis of the wheel - those include weight bearing, and acceleration forces. any situation that sideloads the rim relative to the hub (any cornering will do this) is a transverse load that places the spokes under bending stress. surely you recognize that a wheel being forced hard around the corner is trying to fold on itself? if it weren't for those forces, you could get away with a single set of spokes that went from the center of the hub up to the rim. you need the two sets - one on each side of the hub - to provide lateral stability for cornering.
    spokes in bike wheels are simply tension members. why? because steel wire performs extremely poorly in compression and bending. in fact, as soon as spokes lose tension (the point at which they can be subjected to compression and bending stresses), bike wheels become unstable. by design spokes are always under tension, and therefore not subjected to bending stresses unless the wheel is failing.
    Quote Originally Posted by pvd
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    Hey guys, MF is right on several counts.

    Cold forging or work hardening can increase the strength or hardness of a material, but does not change the elasticity, namely the slope of the stress - strain curve. The s-s curve goes on for longer, but turns over more suddenly, e.g. brittle.

    Also, the bending stiffness of a spoke does not come into play because the spokes are under varying tension, even under wheel side loads. The only forces on a spoke (uncrossed for simplicity) is at the two end points (which are allowed to pivot to a degree), so there is only tension. To get bending you have to press on it in the middle.

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