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  1. #1
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    28h vs 32h.. for a ultralight carbon rim

    I know this has been discussed at length, and ive read many of the threads i could find but nothing that particularly related to light carbon rims..

    Im about to build a set for a Ti 29er hardtail and trying to determine hole count. My traditional logic says more is better, and i've always ran 32h rim my whole life but am tempted to try 28 hole for possibly better 'compliance'? and because a lot of the name brand carbon wheels are 28h. and it broadens my hub deal$ options..

    The rim im leaning towards is a chi carbon 30mm internal @ ~360gr. yes i know it wont have the impact strength of a heavier rim but im willing to take the chance as ive had great lucky with the previous 3 pairs of Chinese carbon rims ive built/owned (from 3 different manufacturers). I always (knock on wood) run adequate psi. Im 160lbs +gear and ride hard on eastcoast tech but have historically never had issues with wheels, except for a pair of 1st gen Crests that constantly needing truing...

    spokes would be a light-ish double butted.. on dt 240s

    reason im going with light rims is because a lightweight hardtail is way more fun, not racing advantage necessarily.

    thanks!

  2. #2
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    Quote Originally Posted by hiss2 View Post
    I know this has been discussed at length, and ive read many of the threads i could find but nothing that particularly related to light carbon rims..

    Im about to build a set for a Ti 29er hardtail and trying to determine hole count. My traditional logic says more is better, and i've always ran 32h rim my whole life but am tempted to try 28 hole for possibly better 'compliance'? and because a lot of the name brand carbon wheels are 28h. and it broadens my hub deal$ options..

    The rim im leaning towards is a chi carbon 30mm internal @ ~360gr. yes i know it wont have the impact strength of a heavier rim but im willing to take the chance as ive had great lucky with the previous 3 pairs of Chinese carbon rims ive built/owned (from 3 different manufacturers). I always (knock on wood) run adequate psi. Im 160lbs +gear and ride hard on eastcoast tech but have historically never had issues with wheels, except for a pair of 1st gen Crests that constantly needing truing...

    spokes would be a light-ish double butted.. on dt 240s

    reason im going with light rims is because a lightweight hardtail is way more fun, not racing advantage necessarily.

    thanks!
    The difference in weight is basically negligible (4.5g/spoke + 0.3g/nipple = 4.8g*4 = 19.2 grams). If you were that serious about weight you'd be looking elsewhere first.

    In terms of performance 28h works perfectly fine for lighter riders. If you're really heavy and aggressive you can expect to true your wheel ever so slightly sooner, maybe have a chance at breaking it easier, etc. Carbon rims are "compliant", but interestingly enough I've never noticed compliance in my wheelset. I'd rather notice "stiffness". Beware of these marketing terms.

    I'd support going 28h, more hub options, which really are the important part. Get a hub and a rim you like and trust.

  3. #3
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    Quote Originally Posted by sissypants View Post
    The difference in weight is basically negligible (4.5g/spoke + 0.3g/nipple = 4.8g*4 = 19.2 grams). If you were that serious about weight you'd be looking elsewhere first.

    In terms of performance 28h works perfectly fine for lighter riders. If you're really heavy and aggressive you can expect to true your wheel ever so slightly sooner, maybe have a chance at breaking it easier, etc. Carbon rims are "compliant", but interestingly enough I've never noticed compliance in my wheelset. I'd rather notice "stiffness". Beware of these marketing terms.

    I'd support going 28h, more hub options, which really are the important part. Get a hub and a rim you like and trust.
    Thanks for the input, makes sense.

    I wasnt considering 28 vs 32 for the weight savings of 8 spokes, but am gonna try lightweight rims to save ~100 grams of rotating mas per wheel..

    realize 'compliance' is a very subjective term.. im more interested in not having it ride like a 35mm 480gr rim 32h strait gauge wheelset that is so damn solid it rattles my fillings loose..

    but considering the choice of less-then-overbuilt rims, i am trying to decided if 32h helps in terms of durability much...

  4. #4
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    I use Sapim Laser spokes with no problems. If those are lighter than the spokes you're looking at I'd consider those. You can get any rim drilled the way you want. I'd stick with 32 on the rear and go 28 on the front which gets less of your weight.

  5. #5
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    Yes, you could get away with 28h IMO, but you don't notice any difference in compliance. It's a good, wide rim and tire size and tire pressure will have more effect on compliance than spoke count alone.

    If your looking for a great spoke option that isn't super pricey check out Sapim Lasers. I'm 205 lbs and have used them on my last 3-4 wheel builds. Light, strong, cheap. Wait, is this the one product that breaks the rule?
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  6. #6
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    IMO, carbon rims can be stiffer and distribute the load better over more spokes, so fewer is OK. I run 28 on mtb. 20f and 24r on road. I don't think it makes a consequential difference on ride compliance but rather on lateral stiffness, where stiffer improves handling, though the dif between 28 and 32 is very small.
    Do the math.

  7. #7
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    Yes, at your weight (I weigh the same), 28h 1.5mm spokes no problem, especially if boost. I have some i30 superlight rims on 28h boost hubs and during the stress relief phase I was bouncing all my weight and couldn't get them to budge. They were like a rock. Also with 28 you can get straight pull hubs which makes lacing a breeze.

  8. #8
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    Quote Originally Posted by Schulze View Post
    Yes, at your weight (I weigh the same), 28h 1.5mm spokes no problem, especially if boost. I have some i30 superlight rims on 28h boost hubs and during the stress relief phase I was bouncing all my weight and couldn't get them to budge. They were like a rock. Also with 28 you can get straight pull hubs which makes lacing a breeze.
    cool guess all opinions point towards 28.. which superlight i30 rim did you get?

  9. #9
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    If compliance is a concern its going to fall on the construction of the rim. Rim depth & carbon lay up are primary factors. I talked to a US based carbon rim manufacture and was told if compliance was my #1 concern I might be disappointed in the overseas variety.

  10. #10
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    Quote Originally Posted by hiss2 View Post
    cool guess all opinions point towards 28.. which superlight i30 rim did you get?
    I got the Carbonfan T800, XY series iirc.

  11. #11
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    Quote Originally Posted by keen View Post
    If compliance is a concern its going to fall on the construction of the rim. Rim depth & carbon lay up are primary factors. I talked to a US based carbon rim manufacture and was told if compliance was my #1 concern I might be disappointed in the overseas variety.
    If I was them, that's probably what I'd say too.

    Looking for compliance in rims is ridiculous. Rims should be stiff so they can track, hold a line and transfer power.

    I have the ultralight Oxive carbon rims. I raced them this last season. They did well. They weigh an amazing 290g/rim.
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  12. #12
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    Question for you guys. Thought I'd jump in here because it's related.

    I picked up a DT Swiss 180 CL front hub for $20 recently. I have 32 spokes from a wheel Iíve used twice, whose 240 Disc rear hub is being used in a new road wheel.

    Say I want to use 28 of those 32 spokes in a new front wheel build. Per various spoke calculators, the needed spokes would be within a millimeter of the spokes I currently have.

    The only stipulation is that that only works if I go 2x, instead of 3x. Iíve never done this before. I know ENVE does it, but it just seems strange to me. I'm 143lbs, relatively quick but smooth XC racer. Enjoy rocky terrain.

    Anything to be concerned about?


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  13. #13
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    I'm using 2x 29er wheelset I built for my RS1 equipped bike and I can't tell a bit of difference. The math says there will be higher stress on the spokes from braking (vs 3x), but if you already own the spokes, might as well use them.

  14. #14
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    Quote Originally Posted by Schulze View Post
    I'm using 2x 29er wheelset I built for my RS1 equipped bike and I can't tell a bit of difference. The math says there will be higher stress on the spokes from braking (vs 3x), but if you already own the spokes, might as well use them.
    Cool. Thanks. Figured I might as well try to make those (expensive) spokes do something if I've got them just sitting there collecting dust.
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  15. #15
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    You can certainly run 28 hole hubs with the right lightweight carbon rims.

  16. #16
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    Quote Originally Posted by Jayem View Post
    ...Looking for compliance in rims is ridiculous. Rims should be stiff so they can track, hold a line and transfer power.....
    I tend to agree with this as far as tracking and holding a line goes. I doubt it makes any difference regarding power. You got a couple of inches of squish in the tires and if FS, a bunch more inches there. A mm of rim compliance isn't go do anything beneficial as far as ride goes.
    Do the math.

  17. #17
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    Theres no actual good reason to run 28h for mountain biking. Its not more or less compliant, its not more or less stiff, the weight savings is tiny.

    Its just less reliable if you happen to catch a stick or bust a spoke. Thats it. Its just a higher risk. Same for road really, but no one catches sticks on the road.

    If you're XC racing on a short track or all your riding is in fairly small parks, it really doesnt matter. Walking out wouldnt be a big deal. If you like doing 100 mile epic back country riding, this can be huge!

    32h with lasers would be an awesome build. Let your compliance come from tire pressure and suspension.

  18. #18
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    Quote Originally Posted by One Pivot View Post

    Its just less reliable if you happen to catch a stick or bust a spoke. Thats it. Its just a higher risk. Same for road really, but no one catches sticks on the road.

    It happens!
    https://youtu.be/LnXbTJV9_iM?t=277

    Quote Originally Posted by One Pivot View Post
    Theres no actual good reason to run 28h for mountain biking. Its not more or less compliant, its not more or less stiff, the weight savings is tiny.
    Wheels are the #1 place to compromise function in the name of weight savings. On the other hand 80g savings is pretty appealing when there's little fat to trim off a wheelset. Whose to judge?
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  19. #19
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    Quote Originally Posted by One Pivot View Post
    Theres no actual good reason to run 28h for mountain biking. Its not more or less compliant, its not more or less stiff, the weight savings is tiny.

    Its just less reliable if you happen to catch a stick or bust a spoke. Thats it. Its just a higher risk. Same for road really, but no one catches sticks on the road.

    If you're XC racing on a short track or all your riding is in fairly small parks, it really doesnt matter. Walking out wouldnt be a big deal. If you like doing 100 mile epic back country riding, this can be huge!

    32h with lasers would be an awesome build. Let your compliance come from tire pressure and suspension.
    Sure there is, building a light wheelset that is still adequately stiff and strong. I agree that 32 is great for just about everything, but there's no significant downside to 28 for something like an XC race wheelset and you lose a bit of rotational weight, that's all win. When you start getting much less on the spoke count, I would say those other things start to get compromised.
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  20. #20
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    I prefer 28h because that's 8 less spokes to buy/lace/tension and straight pull hubs are 28 usually. I'm spec'ing straight pull on my boost wheels because lacing is oh so easy that I can do it while watching a tv show. So that's two good reasons in my book.

  21. #21
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    I just ordered a 150x12 hub and 28h 27.5 rim from ebay and like the above poster I will string it up while watching tv. I chose 28h not for any reasons except i got laid off on Friday and needed a good cheap rear wheel and purchased these liquidated items. But 28h must still be a good build because its going on my freeride bike, Sun Ringle wouldnt have made a 28H 12mm thru axle x150 rear hub
    Cheap people buy things twice

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