Results 1 to 40 of 40
  1. #1
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282

    the bracing angle vs tension symmetry trade-off

    I know this is a contentious topic, but here goes anyway . . .

    Are there any accepted parameters to assess strength vs lateral stiffness trade-offs in some quantified way? Or even a quantified argument for minimum bracing angle?

    My personal context for this is a need to build a 157mm Super Boost rear wheel for a Pivot Switchblade. Please lets avoid debating the desirability of this "standard" . . . it is what it is, and frames need wheels.

    I'm comparing different hub options. Any 150/157mm DH rear hub can be used, most of them with symmetric flange spacing. There are also a few (very few) hubs that push the NDS flange further outboard, which increases NDS bracing angle and "total" bracing angle, while (of course) dramatically increasing spoke tension disparity. These asymmetrically flange-spaced hubs are generally either very expensive ($near $400 for SRAM XO DH or i9) or impossible to acquire (DT 350 super boost which is OEM custom to Pivot which Pivot inexplicably refuses to resell as hubs or wheels, and DT refuses to sell thru distributors or direct).

    So essentially I would like to quantify the potential benefit (if any) of using an expensive and/or rare hub with widely spaced NDS flange versus an affordable, widely available hub w/ equally spaced flanges (DT 350 157 DH).

    Using a SRAM XO DH, retail DT 350 157 and Pivot proprietary DT 350 as examples, 3X lacing for all (Pivot hub can only do 3X so keeping apples-to-apples) and the chosen rim being normally drilled (not asymmetric/offset), the bracing angles work out to:
    retail 350: NDS = 5.3deg DS = 5.3deg 100% L/R tension
    Pivot 350: NDS = 7.7deg DS = 5.0deg 153% L/R tension
    retail XO: NDS = 8.2deg DS = 5.5deg 149% L/R tension

    As a baseline comparison, the same rim on DT 350 IS 148mm Boost gives:
    148 350: NDS = 7.2deg DS = 4.6deg 157% L/R tension

    Various schools of thought could be applied. Is "best" the one with the least-worst-minimum? Or the most-best-maximum? Or the most equal tension? Obviously its some mix of the three . . . one needs a reasonable minimum bracing angle, and more symmetry is better if all else equal, but at what point does in increase in one justify a decrease in another??

    Personally, I am inclined to dismiss the greater NDS bracing angle of the X0 or Pivot hub. One reason is that, all else equal, increased bracing angle on one side only improves lateral stiffness in one direction only (forces opposing the angle) so the NDS advantage quite literally only applies to half your turns or impacts, no? But another reason is that these DH spaced hubs already achieve a relatively high DS bracing angle, so gaining NDS bracing angle would seem relatively unhelpful compared to the dramatic increase in spoke tension inequality. See above where a DT 350 157mm hub gets 5.3deg minimum bracing angle versus 4.6deg on the same hub with Boost 148mm spacing.

    I'm heavily biased toward DT's ratchet freehubs since I've never, ever blown one up (but I've blown nearly 10 pawl freehubs from Shimano, Easton, Formula and Powertap). So I'm skeptical of any pawl designs, even i9 (queue the haters). Plus the unequal-spaced flange hubs from i9 and SRAM are nearly $400, whereas I can get the DT for <$150. I'll have a heavier wheel, but its affordable and symmetric/equal tension.

    So at this point I don't really need help choosing a hub, but I'd like to learn/know more about quantifiable benefits of the proverbial angle/tension tradeoff.

    I've also developed skepticism toward some of Pivot's hype for their Super Boost hubs. The additional NDS spacing does f*&X-all for the lateral tension, reduces strength (due to tension asymmetry) and on top of that they go to 28H hubs/rims. Especially when their stock DT rims are symmetrically drilled (so can't "exploit' the greater NDS spacing for greater effective DS spacing). At first I tried begging for access to their hubs, but at this point the 32H retail DH version of DT 350 seems arguably better.

  2. #2
    Chris Bling
    Reputation: dustyduke22's Avatar
    Join Date
    Aug 2006
    Posts
    2,501
    In short, a mere mortal like yourself or me is not going to be able to tell the difference between 157 and super boost 157.

    Sent from my SPH-L720T using Tapatalk
    The obsession of wheels fused with the passion of cycling
    Affordable Custom Wheels

  3. #3
    mtbr member
    Reputation: One Pivot's Avatar
    Join Date
    Nov 2009
    Posts
    7,706
    I don't think there's any point or benefit to try to chase even wider hubs on the widest spaced standard.

    Basically, the narrowest hub you could run will be very, very stiff.

    It's worth chasing a wide DS flange on 130mm road hub. Even then some people think it's silly hair splitting.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Nov 2010
    Posts
    3,351
    Quote Originally Posted by InertiaMan View Post
    Personally, I am inclined to dismiss the greater NDS bracing angle of the X0 or Pivot hub. One reason is that, all else equal, increased bracing angle on one side only improves lateral stiffness in one direction only (forces opposing the angle) so the NDS advantage quite literally only applies to half your turns or impacts, no? But another reason is that these DH spaced hubs already achieve a relatively high DS bracing angle, so gaining NDS bracing angle would seem relatively unhelpful compared to the dramatic increase in spoke tension inequality.
    Actually, if we look at the data on Damon Rinard's wheel stiffness test, there's an insignificant difference in lateral stiffness between the left & right side of a dished wheel.
    Wheel Stiffness Test
    (seen point #3)
    There's a marginal difference but it's well within the measurement error in most cases.

    I am not an engineer, but it looks like a wider flange spacing, even if it's asymmetrical, will give added stiffness in both directions and not just the side that's spaced out further. Whether that's worth the trade-off of uneven spoke tensions is a whole 'nother can of worms.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Jun 2016
    Posts
    561
    https://i.imgur.com/rXEZrSF.png

    Super Boost wins. I'm not sure how you got your angles, but I based this on Chris King hubs and 29er rims with a middle-of-the-road profile.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by alexdi View Post
    https://i.imgur.com/rXEZrSF.png

    Super Boost wins. I'm not sure how you got your angles, but I based this on Chris King hubs and 29er rims with a middle-of-the-road profile.
    Not sure what point you're intending to make, in part because the .png gives me a "you don't have permission" error.

    The Chris King 157mm hubs are symmetric like the DT 350 hubs (albeit 27.4mm versus 26.7mm center-to-flange) so aren't really Super Boost, "just" another example of a 157mm DH symmetric hub. We can debate Chris King quality versus DT 350 (both freehubs are pretty bullet proof no doubt) and value ($150 versus $500) but the bracing angle and wheel structure are very similar so I wouldn't expect a meaningful difference in stiffness or strength.

    i'm using spocalc for the angles. I get 5.6deg on both sides for the Chris King 157mm hub, as opposed to 5.4deg on the DT 350 157, in both cases w/ 601mm ERD for DT XM 481.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by One Pivot View Post
    I don't think there's any point or benefit to try to chase even wider hubs on the widest spaced standard.
    That's the conclusion I'm coming to . . . especially if it costs you symmetric spoke tension.

  8. #8
    Barely in control
    Reputation: Schulze's Avatar
    Join Date
    Feb 2007
    Posts
    1,715
    Personally, I am inclined to dismiss the greater NDS bracing angle of the X0 or Pivot hub. One reason is that, all else equal, increased bracing angle on one side only improves lateral stiffness in one direction only (forces opposing the angle) so the NDS advantage quite literally only applies to half your turns or impacts, no?
    No. It improves lateral stiffness of the whole wheel.

    Do this thought experiment. You push on the rim on the drive side toward the nds. The drive side spokes tension a minuscule amount to resist your force. But the other side of the hub is attached with spokes to the opposite end of the rim (180 degrees from your push). And that rim is anchored to the hub with the NDS spokes. It's a statically indeterminate system.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Jun 2016
    Posts
    561
    Refresh the page, the image should reload. Problem on Imgur's side. My point was to convey where my numbers came from so they can be reproduced. I used this calculator:

    Freespoke

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jun 2016
    Posts
    561
    Quote Originally Posted by Schulze View Post
    No. It improves lateral stiffness of the whole wheel.

    Do this thought experiment. You push on the rim on the drive side toward the nds. The drive side spokes tension a minuscule amount to resist your force. But the other side of the hub is attached with spokes to the opposite end of the rim (180 degrees from your push). And that rim is anchored to the hub with the NDS spokes. It's a statically indeterminate system.
    I'm not sure I follow this. If you push one side, that side goes up in tension and the opposing side goes down. The actual movement of a given rim for a given amount of force, though, should depend on the stiffness of the spoke configuration of the side you're pushing. The opposing side shouldn't have an impact because spokes don't provide any support in compression.

  11. #11
    Here, diagonally!
    Reputation: JACKL's Avatar
    Join Date
    Sep 2011
    Posts
    2,019
    I don't know enough to comment on the technical aspects of this regarding which is stronger. However I've been running 150 hubs since 2014, so had to consider some of these questions. In my opinion, you want the widest spaced hub, then just lace it an Asysmmetrical rim. On a symmetrical rim, I'd still probably want more spacing on the NDS, but I really can't say for certain that would make the wheel any stronger. However it sounds like Pivot had DT build a hub with wider NDS spacing, which tells me there is some benefit to it.

    Regardless, it's a nice problem to have.

  12. #12
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277
    Quote Originally Posted by InertiaMan View Post
    Are there any accepted parameters to assess strength vs lateral stiffness trade-offs in some quantified way?
    No.
    The whole exercise of "evaluation" may be something you're interested in, and that would be the only measurable benefit of the process. You'll never know if the selection you end up making was the best or better than the other options or anything, really. It will probably be good enough, because there are few if any options that are not.
    Different hub manufacturers skin this cat in different ways (look at Hope specs vs. American Classic, for example), and they all work fine.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  13. #13
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by alexdi View Post
    I'm not sure I follow this. .
    I'll use clock dimensions to illustrate what @Schulze described. Say your bike is in the repair stand, you are facing the rear wheel cassette side. If you push on the wheel at 12 o'clock, it will add tension to the DS spokes near 12 o'clock, and (as you observed) reduce tension in the NDS spokes near 12 o'clock. @Schulze is saying that this will also add tension to the NDS spokes near 6 o'clock. In other words, the rim is "pivoting" about an axis that corresponds to spokes at 3 and 9 o'clock.

    I understand what he's saying, but I'm skeptical. It assumes that the rim is perfectly rigid, whereas the reality that rims are not laterally rigid is the entire basis for the discussion here about bracing angles. It reminds me of the (false) myth that the spokes between 11 and 1 o'clock increase in tension when a wheel supports a load at the axle.

  14. #14
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277
    Quote Originally Posted by alexdi View Post
    I'm not sure I follow this.
    That's because it's bogus.
    Quote Originally Posted by alexdi View Post
    If you push one side, that side goes up in tension and the opposing side goes down. The actual movement of a given rim for a given amount of force, though, should depend on the stiffness of the spoke configuration of the side you're pushing. The opposing side shouldn't have an impact because spokes don't provide any support in compression.
    The other side spokes do have an impact.
    It doesn't matter that they aren't in compression.
    Their force:deflection relationship is part of the force balance. If at 1mm of rim deflection tension has dropped by 25% that's going to feed into the overall force:deflection of the rim differently than if at 1mm of rim deflection their tension had dropped by 100%.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  15. #15
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by meltingfeather View Post
    Different hub manufacturers skin this cat in different ways (look at Hope specs vs. American Classic, for example), and they all work fine.
    This is sort of my point: why are manufacturers choosing one way versus the other?

    Confining this to 150mm hubs:
    Onyx, Shimano Saint, SRAM XO and Pivot SB157 all use asym flanges.
    DT, Chris King, Hope use equal spaced flanges

    American Classic is a particularly odd example. They have asym flange spacing on almost all their hubs, including the 150 DH hub. But then on their Boost rear hub they suddenly change to symmetric spacing (not exactly: the NDS spacing is inexplicably 2mm shorter than DS!!) and publish articles in Pinkbike extolling the virtues of symmetric bracing angles and the evils of asym rims.

    My paraphrasing of your point is: if half the OEMs are doing it one way, and half the other, there probably isn't a significant benefit one way or the other. I tend to agree (reminds me of the guidance re: leading/trailing spoke orientation on disc side). But I'd still like to hear the geometric rationales.

  16. #16
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by alexdi View Post
    Refresh the page, the image should reload. Problem on Imgur's side. My point was to convey where my numbers came from so they can be reproduced. I used this calculator:

    Freespoke
    Refreshed. Even tried 3 browsers. Still not loading. "Access denied, you do not have permission . . . ."

    It wouldn't be surprising if you got slightly different angles w/ freespoke. Exact angles will depend greatly on ERD and to some extent on the calculator's method of "approximating" the average effective angle among the outside/inside flange spokes, etc. But so long as the same calculator is used for all hubs compared, the comparison is valid.

  17. #17
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by Schulze View Post
    No. It improves lateral stiffness of the whole wheel.

    Do this thought experiment. You push on the rim on the drive side toward the nds. The drive side spokes tension a minuscule amount to resist your force. But the other side of the hub is attached with spokes to the opposite end of the rim (180 degrees from your push). And that rim is anchored to the hub with the NDS spokes. It's a statically indeterminate system.
    I'd like to believe your first statement, in part because it would explain why some hub OEMs maximize the spacing despite the asymmetry. And the essence of my first post was soliciting explanations to support your first statement. But, respectfully, I don't buy your explanation.

  18. #18
    Ride Fast Take Chances :)
    Reputation: alexbn921's Avatar
    Join Date
    Mar 2009
    Posts
    2,385
    Symmetry is better than angle. An offset rim will get you both symmetry and angle. Something like an Ibis 942 or 735.
    If you want aluminum:
    Ibis 738 Aluminum Rim ? Ibis Cycles Online Store

  19. #19
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by alexbn921 View Post
    Symmetry is better than angle. ]
    Then why have nearly all rear hubs been asymmetric since the dawn of the derailleur?

    I don't think you can make such a broad statement. In fact, if one looks at the history of hub design, it implies the opposite of your statement: that angle is always better than symmetry. Nearly all multispeed hubs, for decades before asym rims, had asymmetrically spaced flanges and dished rims. They were gaining angle on the NDS at the cost of symmetry in spoke tension & spoke angle.

    Surely there is a straightforward structural explanation for this?

  20. #20
    Ride Fast Take Chances :)
    Reputation: alexbn921's Avatar
    Join Date
    Mar 2009
    Posts
    2,385
    On a rear hub every degree of bracing angle you can get counts. Hubs and rims used to be narrow on road and mountain bikes. Rear hubs have always been a compromise of effectively using the limited space that's available. Manufactures used all kinds of tricks like half the spokes on non drive-side, large flanges.... to get a stronger wheel.
    Now that hub spacing and rims are wider we can engineer a better wheel. Offsetting the rim holes 6mm on a boost wheel gives a near perfect symmetry and spoke tension while maintaining the largest bracing angle possible. This can add a small amount of weight, but Ibis shed weight and made a strong rim.
    American Classic had to make new hubs, but not rims so they built a stronger wheel with symmetric spacing (Symmetry is better than angle, granted that at very shallow angles this changes). This is BS as they didn't want to make an offset rim that would have given an even strong wheel.
    Having a wheel that responds the same form left to right is the goal.

  21. #21
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277
    Quote Originally Posted by InertiaMan View Post
    This is sort of my point: why are manufacturers choosing one way versus the other?
    Because they're people, so they think differently, and it doesn't matter, so they can get away with it.

    Quote Originally Posted by InertiaMan View Post
    But I'd still like to hear the geometric rationales.
    There aren't any that aren't at least mostly ********, since we all agree that either way works just fine, so one way ISN'T "better."
    If you want to spend time reading vacuous tech speak written by marketing folks pick your favorite manufacturer's website and have at it.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  22. #22
    Ride Fast Take Chances :)
    Reputation: alexbn921's Avatar
    Join Date
    Mar 2009
    Posts
    2,385
    Old but still valid.
    No marketing involved.
    Wheel Stiffness Test

  23. #23
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by alexbn921 View Post
    Old but still valid.
    No marketing involved.
    Wheel Stiffness Test
    Perhaps you missed post #4 above that also referenced Damon's measurements? I've reviewed that data many times over the years, and its helpful, especially in establishing that spoke tension doesn't contribute to lateral stiffness. But it doesn't answer the question I'm posing in this thread. Although Damon does pose essentially the same question in his section #11 "Is There An Optimal Left Flange Location":

    For highest lateral stiffenss, wider flange spacing is always better. Front hubs already have nearly the widest flange spacing that will fit in the fork, but rear hubs have room to widen flange spacing by moving the left flange outboard. But as always there is a tradeoff. The farther the flange moves, the looser the spokes. Loose spokes make for a weaker wheel.

    I'm hoping (and failing) to find examples of how/why a particular sweet spot is chosen in the the stiffness/strength tradeoff.

    Unfortunately, Damon's data doesn't directly address the case of two otherwise identical rear wheels, one with ample DS bracing angle and matching NDS bracing angle, versus another wheel with the same DS angle but greater NDS angle.

    On can infer potential answers from his sections #2, 3 and 10. But no clear, direct measurement.

    As useful as Damon's work was, he ended the work with questions that seem to still be unanswered in a quantified manner: the relative contributions to stiffness of spoke count, flange spacing, rim structure, etc.

  24. #24
    Ride Fast Take Chances :)
    Reputation: alexbn921's Avatar
    Join Date
    Mar 2009
    Posts
    2,385
    Wheels are a very complex system and I haven't found an apples to apples test like you are looking for. If your shooting for a super strong wheel then thicker spokes, more spokes and a strong rim. An offset rim like I linked will give you a better spoke symmetry with the widest bracing angle.
    Good luck.

  25. #25
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277
    Quote Originally Posted by alexbn921 View Post
    If your shooting for a super strong wheel then thicker spokes
    nope
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  26. #26
    Ride Fast Take Chances :)
    Reputation: alexbn921's Avatar
    Join Date
    Mar 2009
    Posts
    2,385
    Quote Originally Posted by meltingfeather View Post
    nope
    very informative.

  27. #27
    mtbr member
    Reputation:
    Join Date
    Jun 2016
    Posts
    561
    Quote Originally Posted by InertiaMan View Post
    I'll use clock dimensions to illustrate what @Schulze described.
    Makes more sense, thanks. I suspect, as you say, it's more true with a stiff rim. Low-spoke-count carbon wheels on road bikes are prone to brake rub because relative to the spokes, the rim is very laterally rigid (which is another way of saying the cross-section is stiff in torsion). Alloy rims can deflect laterally in one area without affecting the opposing area.

    https://i.imgur.com/RFRMiee.png

    I had a second go with Imgur. I extrapolated this method to create the percentages:

    https://www.noxcomposites.com/sites/...comparison.png

    Short of actually buying a bunch of hubs, the best way to answer this question is by playing with one of the many FEA models available online. Unlike a lot of wheel questions, this one lends itself to simplified modeling. I'd be curious to see the spoke stress distribution for rims of varying stiffness in response to a lateral force.

  28. #28
    mtbr member
    Reputation:
    Join Date
    Jun 2016
    Posts
    561
    Quote Originally Posted by alexbn921 View Post
    very informative.
    If we're comparing butted spokes, you're probably right. If the thicker spoke is straight-gauge, perhaps not. Straight-gauge spokes tend to cost less and don't have the same heat-treatment, so while they may be stiffer, they won't necessarily be stronger. Straight gauge also has a higher probability of fatigue failure at the hub and the spoke elbow because, in absence of a thin spoke section, these areas bear more of the cyclic stress.

  29. #29
    Ride Fast Take Chances :)
    Reputation: alexbn921's Avatar
    Join Date
    Mar 2009
    Posts
    2,385
    Quote Originally Posted by alexdi View Post
    If we're comparing butted spokes, you're probably right. If the thicker spoke is straight-gauge, perhaps not. Straight-gauge spokes tend to cost less and don't have the same heat-treatment, so while they may be stiffer, they won't necessarily be stronger. Straight gauge also has a higher probability of fatigue failure at the hub and the spoke elbow because, in absence of a thin spoke section, these areas bear more of the cyclic stress.

    I was talking about equal level spokes.
    Something like these.
    https://www.dtswiss.com/Components/Spokes/DT-champion

  30. #30
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277
    Quote Originally Posted by alexbn921 View Post
    very informative.
    it was accurate at least.

    the strength of a wheel (load it can bear before failure) is determined by the spoke tension, not the spoke gauge. In fact, the thinner the spoke gauge, the more load sharing between spokes is encouraged, which can increase strength, though it depends so much on rim construction that there isn't any general rule.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  31. #31
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277

    the bracing angle vs tension symmetry trade-off

    Quote Originally Posted by alexdi View Post
    If we're comparing butted spokes, you're probably right. If the thicker spoke is straight-gauge, perhaps not. Straight-gauge spokes tend to cost less and don't have the same heat-treatment, so while they may be stiffer, they won't necessarily be stronger. Straight gauge also has a higher probability of fatigue failure at the hub and the spoke elbow because, in absence of a thin spoke section, these areas bear more of the cyclic stress.
    and confusion skyrockets...
    1. spoke strength does not translate into wheel strength, so thicker spokes NEVER make a stronger wheel.
    2. Straight gauge spokes absolutely DO get the same heat treatment, what they don't have is the additional tensile strength typically imparted by cold forging... again irrelevant to strength.
    3. once you venture off into cyclic stress you're no longer talking about strength, so that further confuses this already confused issue, IMO.
    Last edited by meltingfeather; 05-11-2017 at 01:16 PM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  32. #32
    mtbr member
    Reputation:
    Join Date
    Jun 2016
    Posts
    561
    Sigh. I'll concede the point about cold forging, but not the rest. Lots of differing opinions on the relationship between strength and fatigue and the importance of a spoke's tensile strength.

  33. #33
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277
    Quote Originally Posted by alexdi View Post
    Sigh. I'll concede the point about cold forging, but not the rest. Lots of differing opinions on the relationship between strength and fatigue and the importance of a spoke's tensile strength.
    There may be many opinions, but the few facts are pretty straightforward.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  34. #34
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by meltingfeather View Post
    2. butted spokes absolutely DO get the same heat treatment, what they don't have is the additional tensile strength typically imparted by cold forging... again irrelevant to strength.
    Don't you mean UNbutted spokes?

    I know you know this, but perhaps made a typing mistake. The opinions flying around are confusing enough, we don't need typos adding further.

  35. #35
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277
    Quote Originally Posted by InertiaMan View Post
    Don't you mean UNbutted spokes?

    I know you know this, but perhaps made a typing mistake. The opinions flying around are confusing enough, we don't need typos adding further.
    lol good catch. Fixed.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  36. #36
    Here, diagonally!
    Reputation: JACKL's Avatar
    Join Date
    Sep 2011
    Posts
    2,019
    Quote Originally Posted by InertiaMan View Post
    American Classic is a particularly odd example. They have asym flange spacing on almost all their hubs, including the 150 DH hub. But then on their Boost rear hub they suddenly change to symmetric spacing (not exactly: the NDS spacing is inexplicably 2mm shorter than DS!!) and publish articles in Pinkbike extolling the virtues of symmetric bracing angles and the evils of asym rims.
    I had to actually go check that on their website because it's hard to believe. I really hope it's a typo. Otherwise I'm concerned that they don't know what the hell they are doing over there. Maybe someone from AC can set me straight on why they might do this.

  37. #37
    transmitter~receiver
    Reputation: meltingfeather's Avatar
    Join Date
    May 2007
    Posts
    9,277

    the bracing angle vs tension symmetry trade-off

    Quote Originally Posted by JACKL View Post
    Otherwise I'm concerned that they don't know what the hell they are doing over there.
    Shook is a pretty smart guy and has always done things a bit differently. Some good, some goofy.
    The hubs work though.
    My I9 SS hub is not dishless. I was trying to decide if I should mix and match asym rims front and rear because it was going to kill me to build a dished rear SS wheel until I found out I couldn't build dishless regardless of rim offset because of my hub.
    **edit**
    Before somebody gets cute there are no asym options that match the dish in an I9 SS hub.
    And my wheel works just fine.
    Last edited by meltingfeather; 05-12-2017 at 09:43 AM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  38. #38
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    309
    @InertiaMan - I was wondering if you got any further in drawing conclusions. I have just bought a Pivot Trail429 and looking building some wheels. My first thought was to go for the widest spacing, but then I saw Hope and DT have opted for symmetrical flange spacing so exactly the same question occurred to me! Interestingly CK now have 2 front boost hubs, one with symmetrical flanges and one without. https://chrisking.com/blog/676
    If you look at at a typical 135 or 130mm spaced hub then the ratio of flange spacing L:R is about 65%:35% (Hope, CK)
    If you then look at the widest flange super-boost hubs like i9 with 41.4/28.9mm = 59%:41% thats still quite a bit closer to symmetrical than a typical 130mm or 135mm rear hub with the benefit of very wide flanges - so I think wider is better/stronger and you are still going to have less spoke tension asymmetry with a 157mm rear hub than a normal one. I have a Dartmore Revolt Pro cassette hub on order (I wanted 36h which limited the choice even further!) Ill let you know how I get on!

  39. #39
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,282
    Quote Originally Posted by fastfish666 View Post
    @InertiaMan - I was wondering if you got any further in drawing conclusions.
    I didn't draw any brilliant conclusions about the general debate/topic, but I did proceed w/ a wheelbuild. I used a 157mm DT 350 DH rear (symmetric flange spacing), which I found second-hand (but new) for $80. I used a DT 350 front 15x100, and swapped in a Wolftooth boostinator end cap to make it 15x110 with nearly symmetrical flange spacing. Laced up ARC 30 rims (last year's model, center drilled; the 2019 versions are a new offset extrusion).

    The end result is a very inexpensive, but pretty high performance wheelset. Front and rear spoke bracing and tension are essentially equal, and with sufficient bracing angle. Wheels have several hundred hours of trail riding on them, and haven't needed any attention whatsoever.

  40. #40
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    368
    FWIW, I recently specced a new wheel build standard boost. For the front, I opted with CKís newer ISO AB hub that isnít symmetrical and pushes the hub flanges outward. I mainly wanted it for the larger bearings, but hope that with a 2.4mm offset rim profile itíll be close in tension.

Similar Threads

  1. 2016 FSi 1x10 spoke bracing VS 2017 1x11
    By ViperDom in forum Cannondale
    Replies: 0
    Last Post: 10-23-2016, 11:05 AM
  2. Crazy high spoke tension, or tension meter off?
    By tuvok in forum Wheels and Tires
    Replies: 14
    Last Post: 04-25-2016, 05:25 PM
  3. ION 16 Extra bracing
    By scarlet in forum Nicolai
    Replies: 4
    Last Post: 10-06-2015, 02:58 AM
  4. What does max spoke tension for your rim mean? Average tension?
    By happyriding in forum Wheels and Tires
    Replies: 8
    Last Post: 03-23-2014, 11:03 AM
  5. Slack Head Angle + Steep Seat Angle
    By motard5 in forum All Mountain
    Replies: 28
    Last Post: 07-25-2012, 06:12 AM

Members who have read this thread: 31

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

mtbr.com and the ConsumerReview Network are business units of Invenda Corporation

(C) Copyright 1996-2018. All Rights Reserved.