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  1. #1
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    Asymmetric rims on Si bikes

    I am looking to buy a lighter set of carbon wheels for my Scalpel Si and I am a bit confused around which rim profile to choose. A lot of rim manufacturers are now producing asymmetric rim profiles, but since the Scalpel Si and FSi have symmetrically-laced rear ends, does it make sense to use an asymmetric rim or should I stick to symmetric-only?

  2. #2
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    Alchemist!!!

  3. #3
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    Asymmetric rim will result in two different spoke lengths which defeats cannondale intent with having a symmetrical rim laced with off set

    Sent from my E5823 using Tapatalk

  4. #4
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    A lot of online custom wheel builders will give you an option for rear wheel dish as Ai for Cannondale. They also state symmetrical rims only. It's pretty pointless to build a custom wheelset with an asymmetrical rim if it results in worse wheel strength.

    If you had a wheelset already built with an asymmetrical rim though it would work to just redish it. I raced all last season on a set of SRAM Rise 60 wheels that I redished the rear for Ai.

  5. #5
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    Quote Originally Posted by mikeg123 View Post
    I am looking to buy a lighter set of carbon wheels for my Scalpel Si and I am a bit confused around which rim profile to choose. A lot of rim manufacturers are now producing asymmetric rim profiles, but since the Scalpel Si and FSi have symmetrically-laced rear ends, does it make sense to use an asymmetric rim or should I stick to symmetric-only?
    SHORT ANSWER: You definitely need to stick to symmetric rims.

    LONG ANSWER: Ai actually is truly "symmetric" in that the spokes and dish are equal on both sides, so the term "Asymmetric Integration" is kind of a misnomer in that sense. Traditional (non-Ai) rear spacing created an uneven dish to the rear wheel, thus having to sometimes require different spoke lengths for a wheel build. "Asymmetric" rims are asymmetric in their cross-section and were developed as freehub/cassettes got wider, the spoke bracing angles created a disparity in spoke tension/dish. The asymmetric spoke bed allowed for spokes to be near equal length and reduced the dish disparity.

    CONCLUSION: Asymmetric rim profiles have nothing to do with Cannondale's Asymmetric Integration. In fact, if you built with an asymmetric rim, it would nullify the benefits.

  6. #6
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    Quote Originally Posted by trauma-md View Post
    SHORT ANSWER: You definitely need to stick to symmetric rims.

    LONG ANSWER: Ai actually is truly "symmetric" in that the spokes and dish are equal on both sides, so the term "Asymmetric Integration" is kind of a misnomer in that sense. Traditional (non-Ai) rear spacing created an uneven dish to the rear wheel, thus having to sometimes require different spoke lengths for a wheel build. "Asymmetric" rims are asymmetric in their cross-section and were developed as freehub/cassettes got wider, the spoke bracing angles created a disparity in spoke tension/dish. The asymmetric spoke bed allowed for spokes to be near equal length and reduced the dish disparity.

    CONCLUSION: Asymmetric rim profiles have nothing to do with Cannondale's Asymmetric Integration. In fact, if you built with an asymmetric rim, it would nullify the benefits.
    apparently the answer is not that clear cut....reading on the Italian forum it is very much hub dependent..all very confusing

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    I agree, it is not clear cut. I ran into this when I built wheels for my scalpel-si. Some combos will be very close to symmetric. In the end I chose a symmetric rim which eliminated a few smaller rim brands that I really wanted to try.

  8. #8
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    It is indeed clear cut. "Short Answer: ...stick to symmetric rims"

    If you are wanting to use smaller company, custom builds, with strangely shaped asymmetric rims and different diameter hub flanges...as it sounds like...there might be some hiccups and with spoke sizing/tension, dish, etc.


    Generally, symmetric rims with regular mtb hubs will work fine.

  9. #9
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    The whole point of symmetrical rim and equal spoke lengths is to achieve a stiffer more tension balanced wheel in dynamic conditions. You can build a asymmetrical rim onto the same or any other hub and it will work but you'll have a pretty conventional wheel with all the pitfalls. Cannondale chose the symmetrical path to eliminate boost. And it works very well.

    Sent from my E5823 using Tapatalk

  10. #10
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    So I contacted one of the online stores and this is the answer I received. Not sure if it makes sense or not:

    Thanks for your e-mail and interest in our wheels.

    The use of asymmetric rims on SI frame allow to reach almost the same spokes tension on both sides of the wheel, if hubs with large distance flanges (like Carbon-Ti) are used.
    This way the wheel reaches the best level of lateral stiffness.
    Using hubs with narrow distance flanges (like American Classic) asymmetric rims are not necessary.

    The wheels I was enquiring about were: ROCKY AS33 CARBON 29ER / Carbon-Ti X-HUB SP wheelset from 1.275g - Bikeonline

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    so...not so clear-cut then?

  12. #12
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    It's very clear cut to me.
    Assymetric rim = Assymetric wheel = lower strength
    Symmetrical rim = symmetrical wheel = higher strength and does not require boost hub

    Sent from my E5823 using Tapatalk

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