User Tag List

Results 1 to 10 of 10

Thread: Rim profiles and compliance

  1. #1
    Join Date
    Jun 2008
    Location
    Middle of the mitten
    Posts
    2,426
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Rim profiles and compliance

    How much does rim depth influence the vertical compliance / comfort of a carbon rim.
    Couple of profile examples:
    DT Swiss XMC 1200 Spline 30 vs the 19mm tall Ibis 735?

    Looking at moving from a 24-25 inner width to 30. Same tires (2.5/2.6)
     

  2. #2
    Join Date
    Oct 2012
    Posts
    7,617
    Post Thanks / Like
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    Quote Originally Posted by SpeedyChix View Post
    How much does rim depth influence the vertical compliance / comfort of a carbon rim.
    Couple of profile examples:
    DT Swiss XMC 1200 Spline 30 vs the 19mm tall Ibis 735?

    Looking at moving from a 24-25 inner width to 30. Same tires (2.5/2.6)
    I don't think you can get a rule of thumb as it may vary from manufacturers, construction methods, amount of material used, designated use (XC, enduro, DH...).
    --
    T h o m a s

  3. #3
    Join Date
    Jun 2008
    Location
    Middle of the mitten
    Posts
    2,426
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    Quote Originally Posted by sk_tle View Post
    I don't think you can get a rule of thumb as it may vary from manufacturers, construction methods, amount of material used, designated use (XC, enduro, DH...).
    Makes sense. Some layups can be really stiff regardless of profile.
     

  4. #4
    Join Date
    Sep 2009
    Location
    Wellesley, MA
    Posts
    1,022
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    This 18.5mm deep Stan's Podium SRD rim is compliant!
    IMG_0638.jpg
    Actually, these were really comfortable just-stiff-enough wheels for me, a lightweight,...until they weren't.
    Steve Park

  5. #5
    Join Date
    Aug 2008
    Location
    Flagstaff, Arizona
    Posts
    10,282
    Post Thanks / Like
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    Quote Originally Posted by SpeedyChix View Post
    How much does rim depth influence the vertical compliance / comfort of a carbon rim.
    Couple of profile examples:
    DT Swiss XMC 1200 Spline 30 vs the 19mm tall Ibis 735?

    Looking at moving from a 24-25 inner width to 30. Same tires (2.5/2.6)
    Why carbon?

    If you want compliance lace up a pair on aluminum WTB KOM's in I-29 - great price too

    I wouldn't use the word "compliant" for any carbon rims that I've laced

    - Garro.
    Steve Garro, Coconino Cycles.
    Frames & Bicycles built to measure and Custom wheels
    Hecho en Flagstaff, Arizona desde 2003
    www.coconinocycles.com
    www.coconinocycles.blogspot.com

  6. #6
    Join Date
    Jun 2008
    Location
    Middle of the mitten
    Posts
    2,426
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    Quote Originally Posted by steve garro View Post
    Why carbon?

    If you want compliance lace up a pair on aluminum WTB KOM's in I-29 - great price too

    I wouldn't use the word "compliant" for any carbon rims that I've laced

    - Garro.
    I hear you on compliance of alu vs carbon. It's the add'l weight at the rim. Not terrible, Looks like a 1650g wheelset is possible with alu nips and Sapim Laser dbl butted spokes.
    Maybe I just need to get stronger eh? I know I prefer the ride of alu rims on road vs carbon, At least our roads.

    @sparky33 That's a sad looking wheel there.
     

  7. #7
    Join Date
    Jun 2009
    Location
    Chicago
    Posts
    1,420
    Post Thanks / Like
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    That is next-level compliant. I've been interested in the Zipp 3Zero Moto rims for the compliance-with-toughness angle, but yikes they are expensive.
     

  8. #8
    Join Date
    Jan 2009
    Location
    Wellington, New Zealand
    Posts
    2,410
    Post Thanks / Like
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    There isn't much vertical compliance (movement) going on with any rim - regardless of material.

    Spokes have stretched about 1mm because of the tension they're under. If a rim moved vertically more than this amount of stretch then it's going to start unloading spokes and putting spokes and nipples into a load - no load - load cycle which will cause them to fail incredibly quickly. When under less tension it's also more likely the nipples will loosen themselves so your wheel will go out of true more frequently (incidentally this is the reason a poorly built wheel will go out of true quicker than a well built wheel)

    We've done plenty of static testing and the experiments back this up: There isn't much vertical movement in any wheel.

    So why do some wheels feel more comfortable / compliant than others? Great question. My guess is that you're feeling their *lateral* movement (which varies LOTS between rim models) as compliance because a laterally flexible wheel feels mushy and therefore comfortable.

    Even if rims did move vertically it's not a great place to look for extra suspension travel. Lets say a rim could move 5mm vertically....that 5mm of movement is only ~8% of what a 2.3" tyre will deflect, or ~4% of what your suspension fork will move.

    One really positive thing about modern wide rims is that they give more air volume to a tyre and thus improve the tyres ability to grip and act as suspension. You'll notice a huge difference in how a good modern wheel will ride compared to your 25mm rims, but it won't be the rim's vertical compliance.

  9. #9
    Join Date
    Jun 2008
    Location
    Middle of the mitten
    Posts
    2,426
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    @Tristan Thanks for a great explanation!

    Thread replies have been helpful.
     

  10. #10
    Join Date
    Feb 2013
    Location
    London, UK
    Posts
    4,430
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Rim profiles and compliance

    Quote Originally Posted by Tristan View Post
    There isn't much vertical compliance (movement) going on with any rim - regardless of material.

    Spokes have stretched about 1mm because of the tension they're under. If a rim moved vertically more than this amount of stretch then it's going to start unloading spokes and putting spokes and nipples into a load - no load - load cycle which will cause them to fail incredibly quickly. When under less tension it's also more likely the nipples will loosen themselves so your wheel will go out of true more frequently (incidentally this is the reason a poorly built wheel will go out of true quicker than a well built wheel)

    We've done plenty of static testing and the experiments back this up: There isn't much vertical movement in any wheel.

    So why do some wheels feel more comfortable / compliant than others? Great question. My guess is that you're feeling their *lateral* movement (which varies LOTS between rim models) as compliance because a laterally flexible wheel feels mushy and therefore comfortable.

    Even if rims did move vertically it's not a great place to look for extra suspension travel. Lets say a rim could move 5mm vertically....that 5mm of movement is only ~8% of what a 2.3" tyre will deflect, or ~4% of what your suspension fork will move.

    One really positive thing about modern wide rims is that they give more air volume to a tyre and thus improve the tyres ability to grip and act as suspension. You'll notice a huge difference in how a good modern wheel will ride compared to your 25mm rims, but it won't be the rim's vertical compliance.
    Agree with this, and would highlight the end part: tyres are arguably the most efficient suspension you can get. No forks or rear shock will be able to match the terrain as a tyre does.
    So work on those, and make sure the wheel is a solid base that won't interfere with it.
    Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London


    "Caron, non ti crucciare:
    vuolsi così colà dove si puote
    ciò che si vuole, e più non dimandare"

Similar Threads

  1. Compliance in rear triangle?
    By claritycycler in forum General Discussion
    Replies: 29
    Last Post: 06-24-2019, 12:03 PM
  2. Lovely Bike profiles eRitchie
    By Noteddy in forum General Discussion
    Replies: 21
    Last Post: 11-01-2012, 10:34 PM
  3. Employee Profiles at IBC
    By 1centaur in forum General Discussion
    Replies: 5
    Last Post: 12-05-2009, 03:01 PM
  4. Saddle Profiles
    By henry g. in forum General Discussion
    Replies: 7
    Last Post: 12-01-2009, 11:08 AM
  5. Dates for UCI Aero Component Compliance
    By admin in forum General Discussion
    Replies: 1
    Last Post: 05-14-2009, 01:48 AM

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

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