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  1. #51
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    Quote Originally Posted by rocwandrer View Post
    I was just talking about orientation, not the material quality. Like steel or aluminum, different grades have different properties. With carbon, not just the strength, but also the stiffness varies with the material grade. That's a whole other can of worms.

    As far as orientation, like anything, the answer is "it depends." I don't know the layup schedule for the rims, so it is hard to answer for sure. Also, so many different directions I could go with how to use plain english to explain my thinking... here are a couple incomplete thoughts... Number two was what I was thinking when i made my comment.

    1.) My intuition is that those tows do not look particularly spread, yet they are wide, meaning they are relatively heavy tows (I'm guessing 3k for the "cosmetic" layer in the original photos i commented on). There simply isn't any room in the total weight of a light weight rim for a cosmetic layer. The cosmetic layer also performs the function of providing some of the the needed cross direction strength and stiffness, shear reinforcement, etc. If the fibers were all uni-hoop oriented, the rim would probably crack open just from the inflation pressure of the tire.

    2.) If you can't be bothered to get the cosmetic layer that shows (which is also structurally significant) reasonably well oriented on the rim you use for the promotional photos for the product, how well could you possibly have done the parts that don't show on the every day production unit?

    3.) Since composites are anisotropic (not the same properties in all directions), symmetry is important in symmetrically stressed parts.
    The carbon is Toray 800 which is somewhere on the higher end of the grades from what I have researched. Please correct me if I am wrong. If the UD rims are completely UD including the cosmetic layer, and the carbon is Toray 800, seems like a quality rim with regard to material used. Is there a tow to UD?
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    Quote Originally Posted by indyfab25 View Post
    The carbon is Toray 800 which is somewhere on the higher end of the grades from what I have researched. Please correct me if I am wrong. If the UD rims are completely UD including the cosmetic layer, and the carbon is Toray 800, seems like a quality rim with regard to material used. Is there a tow to UD?
    Toray is a reputable manufacturer of carbon fiber, and T800 is a high grade product. I know nothing about the manufacturer of the rims and don't want to imply I have any special insider info, but it is suspect that they call out T800 as the material... So far as i know, T800 is a bit hard to get your hands on now as Boeing is snapping it all up. It also only comes in 6k and 12k tows, so far as I know.

    As far as "is there a tow to UD?" I don't understand the question.

  3. #53
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    Quote Originally Posted by rocwandrer View Post
    Toray is a reputable manufacturer of carbon fiber, and T800 is a high grade product. I know nothing about the manufacturer of the rims and don't want to imply I have any special insider info, but it is suspect that they call out T800 as the material... So far as i know, T800 is a bit hard to get your hands on now as Boeing is snapping it all up. It also only comes in 6k and 12k tows, so far as I know.

    As far as "is there a tow to UD?" I don't understand the question.
    Is there a tow to UD? You mentioned the tow was off in one of the pics. Does UD have tow? If it is off, how do you tell? It doesn't look like UD has a tow size, but it has to.

    They call the material T800. I have seen this and other manufacturers use that terminology(Toray800 and T800) interchangeably.

    Toray Carbon Fibers America - Application Information
    Lots of cool info there. I just learned a bunch.
    Last edited by indyfab25; 01-15-2012 at 06:53 PM.
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    Quote Originally Posted by indyfab25 View Post
    Is there a tow to UD? You mentioned the tow was off in one of the pics. Does UD have tow? If it is off, how do you tell? It doesn't look like UD has a tow size, but it has to.

    They call the material T800. I have seen this and other manufacturers use that terminology(Toray800 and T800) interchangeably.

    Toray Carbon Fibers America - Application Information
    Lots of cool info there. I just learned a bunch.
    "Tow" is a noun meaning a bundle of filaments. UD is a noun abbreviation meaning unidirectional. unidirectional fabric is made from tows, which are by definition unidirectionally oriented. The tow size is much less important with unidirectional fabric, but still a mfg parameter.

    I see you edited your reply, but if i understood correctly, the issue is that T800 is a high, not standard modulus product in Toray product nomenclature.

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    oh, and "does UD have tow?" what you really mean might be "does UD have/require alignment?" The answer is a resounding yes. And the pictures tell me nothing about the accuracy or correctness of that alignment.

  6. #56
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    Quote Originally Posted by rocwandrer View Post
    "Tow" is a noun meaning a bundle of filaments. UD is a noun abbreviation meaning unidirectional. unidirectional fabric is made from tows, which are by definition unidirectionally oriented. The tow size is much less important with unidirectional fabric, but still a mfg parameter.

    I see you edited your reply, but if i understood correctly, the issue is that T800 is a high, not standard modulus product in Toray product nomenclature.
    Okay. Tow size with UD is less important. Does that mean that UD is generally stronger, as some other carbon manufacturers report?

    I did edit my reply as I was learning after the post and answering questions and learning that some of my statements were wrong.

    There appears to be several variations of the T800.

    Thanks again for the info. If you are getting sick of answering my questions please point me to a couple sites or places I can learn more about this.
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  7. #57
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    this is extremely interesting, any more hands on reports?

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    Quote Originally Posted by indyfab25 View Post
    Okay. Tow size with UD is less important. Does that mean that UD is generally stronger, as some other carbon manufacturers report?

    I did edit my reply as I was learning after the post and answering questions and learning that some of my statements were wrong.

    There appears to be several variations of the T800.

    Thanks again for the info. If you are getting sick of answering my questions please point me to a couple sites or places I can learn more about this.
    First an FYI, most composites folks say "uni" as short for unidirectional, not UD, but they are the same thing.

    I'm not in the habit of looking for basic composites resources on the net, but I'll suggest:

    ACMA: Technical Resources <-- lots of irrelevant stuff about regulations, business, etc, but most of the basic stuff is technically accurate, and including the link throughs, the pit of info is bottomless. Bonus, it is vetted for minimal product bias (some types more innocuous types are allowed, by rule). Many seemingly reputable sources of easy to understand technical info about composites (probably including me to some degree, if i ever manage to be easy to understand) are not totally accurate. One reason is composites are really complicated, and not easy to understand, so simplifications to make stuff easy to understand automatically seem to end up distorting the truth. The (unfortunately more common) reason is that consumers are poorly educated about composites, so marketing departments can pretty much say anything that sounds believable to make their stuff sound good.

    Not really because of tow size being less important, but yes, in general a very well designed and executed unidirectional layup will dramatically outperform a very well designed woven or braided composite. Part of the reason is that on a weight basis, the fiber is more structurally efficient, and you can use less resin and more fiber with uni. Layups made from all uni also tend to be less error tolerant (design, placement, and infusion/impregnation/compaction/consolidation) though. With most consumer products, a braided or woven layer is used for cosmetics on the surface, but that layer is also very structurally useful for crack prevention and shear transfer,etc in an otherwise uni product.

  9. #59
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    Any real experiences with buildup and riding?

    I've been thinking about building up a pair of these just to see how they go. Anyone know the ERD?

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    Quote Originally Posted by nbwallace View Post
    I've been thinking about building up a pair of these just to see how they go. Anyone know the ERD?
    We measured 603.
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    Thanks indyfab

    I assume the build went without incident.

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    Quote Originally Posted by nbwallace View Post
    I assume the build went without incident.
    No issues at all. Nice and stiff. Taped the rim, threw some sealant in, and the tire is still holding air. Tubeless was a breeze.
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    That's very encouraging

    Thanks indyfab. That may make the decision to build these up a no brainer. With Stan's rims at around $90 each (maybe $85) the price is certainly reasonable. The web site makes it sound as if these rims are 75 grams lighter than the Arches. That could make for a really nice set of tubeless wheels.

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    The AM 29r rim weighs around 440g. Tubeless is very good. We have a 28 hole rim here that I threw a Nobby Nic on to test without sealant. Blew up and held air no problem.
    I might build a set up with I9 Enduro wheels. That would be sick.
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  15. #65
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    Here is a pic of the rim bed and bead.
    Attached Thumbnails Attached Thumbnails (Cheap) Chinese Carbon Rims?-p10005131.jpg  

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  16. #66
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    Quote Originally Posted by indyfab25 View Post
    Much, much higher.
    ...
    According to Guitar Ted, Reynolds rims go from 950 – 1150 N.
    Much, much higher than what? He didn't say what tension the "crack" developed at, and 950-1150N is not high, it's average... for aluminum rims.
    Quote Originally Posted by pvd
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    Quote Originally Posted by meltingfeather View Post
    Much, much higher than what? He didn't say what tension the "crack" developed at, and 950-1150N is not high, it's average... for aluminum rims.
    That is a good question. Honestly, I do not know. You raise a good point. I was relying on Reynold's opinion that carbon rims can handle higher tensions. If I am not mistaken, that came from the interview on 29inches.com.
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    Quote Originally Posted by indyfab25 View Post
    The AM 29r rim weighs around 440g. Tubeless is very good. We have a 28 hole rim here that I threw a Nobby Nic on to test without sealant. Blew up and held air no problem.
    I might build a set up with I9 Enduro wheels. That would be sick.
    I've checked through this thread and it wasn't totally clear to me, where did you order these rims? Thanks for the info.

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    Quote Originally Posted by hillharman View Post
    I've checked through this thread and it wasn't totally clear to me, where did you order these rims? Thanks for the info.
    Xiamen BECS.
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    Quote Originally Posted by indyfab25 View Post
    Xiamen BECS.
    Sorry for being dense, but is there a link where the product can be ordered? I'm not having much luck with Google.

    Edit: I think I found it: bikes 29er super light rim products, buy bikes 29er super light rim products from alibaba.com

  21. #71
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    Quote Originally Posted by AZ.MTNS View Post
    Okay, I did not realize that was a crack, it looks like a scribe line in the photo. Thanks.<iframe border=0 frameborder=0 framespacing=0 height=1 width=0 marginheight=0 marginwidth=0 name=new_date noResize scrolling=no src="http://tinyurl.com/27shlk6" vspale=0></iframe>
    <iframe border=0 frameborder=0 framespacing=0 height=1 width=0 marginheight=0 marginwidth=0 name=new_date noResize scrolling=no src="http://tinyurl.com/yz4gjyd" vspale=0></iframe>
    It doesnt look like a crack at all

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    I am immune to your disdain.

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    Quote Originally Posted by hillharman View Post
    I've checked through this thread and it wasn't totally clear to me, where did you order these rims? Thanks for the info.
    looks like they making it easier to order

    carbon 29er wheel mountain bike clincher - light-bicycle

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    Quote Originally Posted by bigdog100 View Post
    looks like they making it easier to order

    carbon 29er wheel mountain bike clincher - light-bicycle
    I wonder if those hubs are any good. The price for the full wheelset is crazy.

  25. #75
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    Indyfab, what's the kind of spoke tension you've used for the build? The range I got from light-bicycle.com was a tad hight.

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    Quote Originally Posted by indyfab25 View Post
    That is a good question. Honestly, I do not know. You raise a good point. I was relying on Reynold's opinion that carbon rims can handle higher tensions. If I am not mistaken, that came from the interview on 29inches.com.
    light-bicycle told me max spoke tension is 180 kgf. To compare, most people I know build aluminum rims to 110-120 kgf. Stans says to only take theirs to about 95-100 kgf (and that's been raised, they used to say 85-90).

    I figure I'll build mine to 120-125 kgf and it should make for a nice stiff wheel, even with the low spoke count I ordered (28 hole)
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  27. #77
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    Quote Originally Posted by indyfab25 View Post
    The AM 29r rim weighs around 440g. Tubeless is very good. We have a 28 hole rim here that I threw a Nobby Nic on to test without sealant. Blew up and held air no problem.
    I might build a set up with I9 Enduro wheels. That would be sick.
    Well, the 440g kind of sucks, since they advertise 400g +/- 10g.

    But the easy tubeless is good! I take it you just ran a layer of Stan's 25mm yellow tape?
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    Quote Originally Posted by Jwiffle View Post
    light-bicycle told me max spoke tension is 180 kgf. To compare, most people I know build aluminum rims to 110-120 kgf. Stans says to only take theirs to about 95-100 kgf (and that's been raised, they used to say 85-90).
    All stan's did was change what used to be a range of max. tension to a fixed number. They didn't raise the max tension specs.
    180 kgf is ridiculous. i'd like to see someone try that... from behind a plexiglass shield.
    Quote Originally Posted by Jwiffle View Post
    I figure I'll build mine to 120-125 kgf and it should make for a nice stiff wheel, even with the low spoke count I ordered (28 hole)
    spoke tension does not affect stiffnes.
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    im thinking about a complete set with db881/882 hubs. $540 is a crazy price and those hubs seem pretty good.

  30. #80
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    Quote Originally Posted by meltingfeather View Post
    spoke tension does not affect stiffnes.
    Ok, then I'll build them to 25 kgf tension, and they'll be just as stiff.


    Spoke tension, of course, is not the end-all of building a stiff wheel, but it obviously plays a roll. I haven't had an issue with stiffness with my Arches, though I built them to 90 kgf. (Stan's recommendation at the time). But spoke tension does play a part in the stiffness of the wheel. Mainly, seeing as everything I've read about carbon rims is that they build into stiff wheels, and they should be decently stiff if built to normal or slightly higher spoke tension.
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    Quote Originally Posted by figo View Post
    Indyfab, what's the kind of spoke tension you've used for the build? The range I got from light-bicycle.com was a tad hight.
    A reading of 20 on the DT Swiss tensiometer.

    I'm a bit new at the art of wheel building.
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  32. #82
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    This thread is about to go to ****e arguing about tension.

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    Last thing I wanted to achieve with my question is to re-open the next 1000+ post fit on a spoke tension in general. I've read many of those on this board and I kind of understand what meltingfeather is saying with the spoke tension not affecting stiffness.

    The 180 kgf was what I heard from light-bikes as well and it feels high (if not ridiculous). What I was after is the kind of tension people have used to build the wheel without going to these ranges.

    I've build most of my alumium wheels (road/mtb) with 130 kgf for the drive side and NDS to get the correct dish, but on some hubs I've found the NDS to feel a bit under-tensioned. I've only build one wheel with stan's, a Arch29 and kept with the 100kgf, as it was a front wheel the difference in spoke tension between DS and NDS was a fair bit smaller.

    So, on these rims, what would be reasonable tension? If the recommended 180kfg is insane and 130kgf is what many aluminium rims can take, would it be safe to go higher on these?

  34. #84
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    internal bead width listed as 23mm for 29er rim, but no such spec listed for 26" rim. anyone know? (i know this is a 29er thread, just curious)
    Last edited by clarkalewis; 01-19-2012 at 02:15 AM.

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    Quote Originally Posted by Jwiffle View Post
    Ok, then I'll build them to 25 kgf tension, and they'll be just as stiff.
    They will... until spokes go slack from a rider sitting on the bike.
    Tension is where wheels get their strength (the load they can bear without spokes going slack), which is also a consideration, though a separate one.
    Quote Originally Posted by Jwiffle View Post
    But spoke tension does play a part in the stiffness of the wheel.
    No it does not. For that to be true, the elasticity of the spokes would have to change with tension. It does not.
    Spoke tension does change the feel of the wheel, possibly due to natural frequency, but it has no effect on stiffness.
    Quote Originally Posted by Jwiffle View Post
    Mainly, seeing as everything I've read about carbon rims is that they build into stiff wheels, and they should be decently stiff if built to normal or slightly higher spoke tension.
    Carbon rims build into stiff wheels because the rims themselves are incredibly stiff. They will be stiff no matter the spoke tension you build them to or even the spoke gauge you choose. They can also handle higher tension than aluminum rims, but the "benefit" of cranking the tension stoopid high (i.e., 180 kgf, not saying you intended to do that, just using it as an example), has to be weighed against the negative impacts of extremely high and possibly critical stresses elsewhere in the wheel... like at the hub flanges and nipples.

    Thiese exchanges where you wing it and try to call people out that actually know something aren't going so well for you. surprise...

    Thanks for the neg rep, btw.

    figo & Admin_X, I ain't going there.
    I build carbon mtb rims to 115-120 kgf. There is no need or benefit to going any higher.
    Quote Originally Posted by pvd
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    Quote Originally Posted by indyfab25 View Post
    A reading of 20 on the DT Swiss tensiometer.

    I'm a bit new at the art of wheel building.
    Do you mean the Park tensiometer? or 2.0mm on the DT Swiss meter?

    Also, the reading is meaningless without the spoke gauge in either case.
    Quote Originally Posted by pvd
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    Quote Originally Posted by meltingfeather View Post
    They will... until spokes go slack from a rider sitting on the bike.
    Tension is where wheels get their strength (the load they can bear without spokes going slack), which is also a consideration, though a separate one.

    No it does not. For that to be true, the elasticity of the spokes would have to change with tension. It does not.
    Spoke tension does change the feel of the wheel, possibly due to natural frequency, but it has no effect on stiffness.

    Carbon rims build into stiff wheels because the rims themselves are incredibly stiff. They will be stiff no matter the spoke tension you build them to or even the spoke gauge you choose. They can also handle higher tension than aluminum rims, but the "benefit" of cranking the tension stoopid high (i.e., 180 kgf, not saying you intended to do that, just using it as an example), has to be weighed against the negative impacts of extremely high and possibly critical stresses elsewhere in the wheel... like at the hub flanges and nipples.

    Thiese exchanges where you wing it and try to call people out that actually know something aren't going so well for you. surprise...

    Thanks for the neg rep, btw.

    figo & Admin_X, I ain't going there.
    I build carbon mtb rims to 115-120 kgf. There is no need or benefit to going any higher.
    I dont know if we mean different things or what by stiffness, but i know if i build a wheel to only 25 kgf, ill have no trouble mking the wheel rub the stays whenn riding, but wont have that problem building them to normal tension. And no , i did not suggest they be built to some ridiculous tension, like 180 would be. I jsaid i would build them to a normal tension of 120.

    For the record, i did not neg rep you. I have never used the silly rep thing, pos or neg.
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    Quote Originally Posted by Jwiffle View Post
    I dont know if we mean different things or what by stiffness, but i know if i build a wheel to only 25 kgf, ill have no trouble mking the wheel rub the stays whenn riding, but wont have that problem building them to normal tension.
    Once spokes go slack, all bets are off stiffness wise, and that's what would happen to a 25 kgf wheel.
    Quote Originally Posted by Jwiffle View Post
    And no , i did not suggest they be built to some ridiculous tension, like 180 would be. I jsaid i would build them to a normal tension of 120.
    We're on the same page in that regard, it just seemed like you were relating tension and wheel stiffness. Going from 100kgf to 120kgf will give you a stronger wheel, but not a stiffer one.
    Quote Originally Posted by Jwiffle View Post
    For the record, i did not neg rep you. I have never used the silly rep thing, pos or neg.
    consider that comment aimed at whoever did, then.
    Quote Originally Posted by pvd
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    Quote Originally Posted by Adim_X View Post
    This thread is about to go to ****e arguing about tension.
    I agree. Everyone knows that nipple color is more revelant when talking about stiffness.

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    Quote Originally Posted by meltingfeather View Post
    We're on the same page in that regard, it just seemed like you were relating tension and wheel stiffness. Going from 100kgf to 120kgf will give you a stronger wheel, but not a stiffer one.
    I think our "argument" was kind of silly. In my original statement, I was responding to what tension should be used, and I mentioned I would use a normal to slightly high tension of 120-125 kgf. But I can see how you took it as relating tension and wheel stiffness. Which I was, and generally, I was wrong on that aspect.

    I went back and reread the book by Brandt and searched a couple other sites. I guess I had for some reason forgotten what I had previously learned and figured that if super-low tension would make for a super-flexy wheel, that higher tension would make it stiffer, at least to a degree. Not to mention that I have seen wheel manufacturers state that the high tensions they allow make for a stiffer wheel (Koolstof for one).

    I did find a site with various tests and theories that state that spoke tension does play a role in wheel stiffness. Great wheel test – Part 3 – Stiffness | Roues Artisanales Their data asserts that "high tensioned spokes...delay the moment when the wheel loses all its stiffness." If I'm understanding them correctly, they're saying that the higher tension doesn't necessarily add stiffness, just keeps it from losing stiffness under load (i.e., keeps the side being de-tensioned under load from going slack, causing the loss in stiffness).

    Brandt does recommend building wheels to just under the max tension the rim will take - but for wheel strength, not stiffness. But I'm not about to try to take a wheel up to 170+ kgf! Brandt does, though, state that spoke thickness plays a part in the stiffness of the wheel.

    I think, though, that we were more in agreement overall than not. 180kgf is too high to build a wheel, and normal tension in the 120 kgf range should be fine.
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  41. #91
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    Quote Originally Posted by LowOnO2 View Post
    I agree. Everyone knows that nipple color is more revelant when talking about stiffness.
    not only stiffness but how well it holds up to certain riding. silver should be fine for xc but make sure it is red (or even better, purple) for am riding.

  42. #92
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    Quote Originally Posted by LowOnO2 View Post
    I agree. Everyone knows that nipple color is more revelant when talking about stiffness.



    Nipple color is very relevant when accounting for stiffness.

  43. #93
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    Quote Originally Posted by AZ.MTNS View Post
    Nipple color is very relevant when accounting for stiffness.
    Sweet! A dick joke! This thread has come full circle now

  44. #94
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    Quote Originally Posted by clarkalewis View Post
    internal bead width listed as 23mm for 29er rim, but no such spec listed for 26" rim. anyone know? (i know this is a 29er thread, just curious)
    It looks like the narrower 29er rim, so if it is the same size, it would be just under 21mm. (the narrower 29er rim's specs as given to me list 20.81mm). But I would send an email to light-bicycle, they'll let you know for sure.
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  45. #95
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    Quote Originally Posted by indyfab25 View Post
    Here is a pic of the rim bed and bead.
    I'm assuming that is the AM rim, correct?

    That rim hook/bead looks very UST-like. Any knowledge of what the lighter XC rim looks like, bead/hook wise?

  46. #96
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    Rim profiles

    In case anyone is interested, here is are the images of the rim profiles light-bicycle sent me

    Standard rim:
    " width="549">

    Wider (AM) Rim:
    " width="549">
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  47. #97
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    Quote Originally Posted by Le Duke View Post
    I'm assuming that is the AM rim, correct?

    That rim hook/bead looks very UST-like. Any knowledge of what the lighter XC rim looks like, bead/hook wise?
    It is what they call the AM rim. I do not know what the other rim bead looks like.
    I am immune to your disdain.

  48. #98
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    subscribed=)

  49. #99
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    Quote Originally Posted by Jwiffle View Post
    In case anyone is interested, here is are the images of the rim profiles light-bicycle sent me
    Ah. The "XC" rims definitely do not appear to have a "UST" profile.

    The "AM" rims do, though.

    Hmmm. Decisions, decisions.

  50. #100
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    Quote Originally Posted by Le Duke View Post
    Ah. The "XC" rims definitely do not appear to have a "UST" profile.

    The "AM" rims do, though.

    Hmmm. Decisions, decisions.
    Since the weight difference is so small (at least, if the come in close to their claimed weights), it seemed a no brainer to go with the AM rims. Fat tires will work better with the wider rims. But should be easy enough to do a stan's conversion to tubeless on the xc rim.
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