Zipp 303 vs 404

Discussion in 'Road Cycling' started by Montymobile, Jan 23, 2003.

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  1. Montymobile

    Montymobile Guest

    I'm considering getting a set of Zipps for road racing and some time trialing. Can anyone give me
    any personal experiential insight on the pros and cons of each set - obviously the 303s are lighter
    and the 404s are more aerodynamic but how much moe efficient are the 404s and how much more are they
    affected by crosswinds etc. Graham
     
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  2. Randomchris

    Randomchris Guest

    Don't forget durability and repairability. This isn't so much of an issue in TTs where you can spot
    pot holes and such like a mile off, but in a road race you might not see a hole in the road until
    it's too late. The 303s have more spokes (I think) and while this makes them less aerodynamic it
    also makes them a lot easier to true.

    Personally, I'd go for 303 then, if the time trialling really bothers you, save up for a more aero
    wheelset later...

    Chris

    Montymobile <[email protected]> wrote in message
    news:[email protected]...
    > I'm considering getting a set of Zipps for road racing and some time trialing. Can anyone give me
    > any personal experiential insight on the pros and cons of each set - obviously the 303s are
    > lighter and the 404s are more aerodynamic but how much moe efficient are the 404s and how much
    > more are they affected by crosswinds etc. Graham
     
  3. Chris M

    Chris M Guest

    I would look at the American Classic 420s. A bit heavier (though not much), but cheaper and a lot
    easier to repair. You also have more build options. Who wants to fool around with CF rims? Not me.

    "Montymobile" <[email protected]> wrote in message
    news:[email protected]...
    > I'm considering getting a set of Zipps for road racing and some time trialing. Can anyone give me
    > any personal experiential insight on the pros and cons of each set - obviously the 303s are
    > lighter and the 404s are more aerodynamic but how much moe efficient are the 404s and how much
    > more are they affected by crosswinds etc. Graham
     
  4. Michael Hoyt

    Michael Hoyt Guest

    The AC 420 isn't like a Ksyrium. The AC is 34 mm deep.

    M

    Andy Coggan wrote:

    > Based on its Ksyrium-like profile, I suspect that the AC 420 wouldn't be much more aerodynamic
    > than a standard box-section rim.
    >
    > Andy Coggan
    >
    > "Chris M" <[email protected]> wrote in message
    > news:[email protected]...
    > > I would look at the American Classic 420s. A bit heavier (though not
    > much),
    > > but cheaper and a lot easier to repair. You also have more build options. Who wants to fool
    > > around with CF rims? Not me.
    > >
    > >
    > > "Montymobile" <[email protected]> wrote in message
    > > news:[email protected]...
    > > > I'm considering getting a set of Zipps for road racing and some time trialing. Can anyone give
    > > > me any personal experiential insight on the pros and cons of each set - obviously the 303s are
    > > > lighter and the 404s are more aerodynamic but how much moe efficient are the 404s and how much
    > > > more are they affected by crosswinds etc. Graham
    > >
    > >
     
  5. Velocat

    Velocat Guest

    Andy Coggan wrote:
    > Based on its Ksyrium-like profile, I suspect that the AC 420 wouldn't be much more aerodynamic
    > than a standard box-section rim.
    >

    The Ksyrium rims are 24mm deep in cross section. The AC420s are 34mm. Why don't you think there
    would be a difference? The Zipp 303s are
    40mm. I would say the AC420 is more Zipp-like than Ksyrium-like.
     
  6. Andy Coggan

    Andy Coggan Guest

    There's much more to rim aerodynamics than just depth.

    Andy Coggan

    "Michael Hoyt" <[email protected]> wrote in message news:[email protected]...
    > The AC 420 isn't like a Ksyrium. The AC is 34 mm deep.
    >
    > M
    >
    > Andy Coggan wrote:
    >
    > > Based on its Ksyrium-like profile, I suspect that the AC 420 wouldn't be much more aerodynamic
    > > than a standard box-section rim.
    > >
    > > Andy Coggan
    > >
    > > "Chris M" <[email protected]> wrote in message
    > > news:[email protected]...
    > > > I would look at the American Classic 420s. A bit heavier (though not
    > > much),
    > > > but cheaper and a lot easier to repair. You also have more build
    options.
    > > > Who wants to fool around with CF rims? Not me.
    > > >
    > > >
    > > > "Montymobile" <[email protected]> wrote in message
    > > > news:[email protected]...
    > > > > I'm considering getting a set of Zipps for road racing and some time trialing. Can anyone
    > > > > give me any personal experiential insight on
    the
    > > > > pros and cons of each set - obviously the 303s are lighter and the
    404s
    > > > > are more aerodynamic but how much moe efficient are the 404s and how much more are they
    > > > > affected by crosswinds etc. Graham
    > > >
    > > >
    > >
     
  7. Andy Coggan

    Andy Coggan Guest

    "VeloCat" <[email protected]> wrote in message news:[email protected]...
    > Andy Coggan wrote:
    > > Based on its Ksyrium-like profile, I suspect that the AC 420 wouldn't be much more aerodynamic
    > > than a standard box-section rim.
    > >
    >
    > The Ksyrium rims are 24mm deep in cross section. The AC420s are 34mm. Why don't you think there
    > would be a difference? The Zipp 303s are
    > 40mm. I would say the AC420 is more Zipp-like than Ksyrium-like.

    Take a closer look:

    http://www.amclassic.com/Rims.html

    Given the squared-off inner circumference, I can't see the extra 10 mm of depth being all
    that helpful.

    Andy Coggan
     
  8. Velocat

    Velocat Guest

    Andy Coggan wrote:
    > "VeloCat" <[email protected]> wrote in message news:[email protected]...
    >
    >>Andy Coggan wrote:
    >>
    >>>Based on its Ksyrium-like profile, I suspect that the AC 420 wouldn't be much more aerodynamic
    >>>than a standard box-section rim.
    >>>
    >>
    >>The Ksyrium rims are 24mm deep in cross section. The AC420s are 34mm. Why don't you think there
    >>would be a difference? The Zipp 303s are
    >>40mm. I would say the AC420 is more Zipp-like than Ksyrium-like.
    >
    >
    > Take a closer look:
    >
    > http://www.amclassic.com/Rims.html
    >
    > Given the squared-off inner circumference, I can't see the extra 10 mm of depth being all that
    > helpful.
    >
    > Andy Coggan

    While the Zipps have more of a bowed lateral surface, the inner circumference looks about as squared
    off as the American Classics. The only cross section I can find is:

    http://www.zipp.com/Wheelsets/303_clincher.html

    I would think that there is some minimum flat area required for the spokes on the inner
    circumference.
     
  9. Michael Hoyt

    Michael Hoyt Guest

    That's a picture of a 350. The 420 tapers to as fine an edge as you'll see on any wheel. I've seen
    them in the flesh <g>.

    M

    Andy Coggan wrote:

    > "VeloCat" <[email protected]> wrote in message news:[email protected]...
    > > Andy Coggan wrote:
    > > > Based on its Ksyrium-like profile, I suspect that the AC 420 wouldn't be much more aerodynamic
    > > > than a standard box-section rim.
    > > >
    > >
    > > The Ksyrium rims are 24mm deep in cross section. The AC420s are 34mm. Why don't you think there
    > > would be a difference? The Zipp 303s are
    > > 40mm. I would say the AC420 is more Zipp-like than Ksyrium-like.
    >
    > Take a closer look:
    >
    > http://www.amclassic.com/Rims.html
    >
    > Given the squared-off inner circumference, I can't see the extra 10 mm of depth being all that
    > helpful.
    >
    > Andy Coggan
     
  10. Andy Coggan

    Andy Coggan Guest

    "VeloCat" <[email protected]> wrote in message news:[email protected]...
    >
    >
    > Andy Coggan wrote:
    > > "VeloCat" <[email protected]> wrote in message news:[email protected]...
    > >
    > >>Andy Coggan wrote:
    > >>
    > >>>Based on its Ksyrium-like profile, I suspect that the AC 420 wouldn't
    be
    > >>>much more aerodynamic than a standard box-section rim.
    > >>>
    > >>
    > >>The Ksyrium rims are 24mm deep in cross section. The AC420s are 34mm. Why don't you think there
    > >>would be a difference? The Zipp 303s are
    > >>40mm. I would say the AC420 is more Zipp-like than Ksyrium-like.
    > >
    > >
    > > Take a closer look:
    > >
    > > http://www.amclassic.com/Rims.html
    > >
    > > Given the squared-off inner circumference, I can't see the extra 10 mm
    of
    > > depth being all that helpful.
    > >
    > > Andy Coggan
    >
    > While the Zipps have more of a bowed lateral surface, the inner circumference looks about as
    > squared off as the American Classics. The only cross section I can find is:
    >
    > http://www.zipp.com/Wheelsets/303_clincher.html
    >
    > I would think that there is some minimum flat area required for the spokes on the inner
    > circumference.

    I've looked at Zipp 303s, and own a Zipp 404 - there is no flat area like that found on the Kysrium
    and AC 420 rims. (BTW, the "bowed" lateral surface of the Zipp is covered by a patent co-owned by
    Hed and now Zipp, and is key to low drag when the wind comes at a slight angle).

    As I responded to Michael Hoyt, there's more to rim aerodynamics than just depth, and I stand by my
    prediction that the AC 420 is likely to more Kysrium-like than Zipp-like in its drag. (Kraig Willet
    should be headed to the Texas A&M wind tunnel any day now...would be nice if we get an AC 420 wheel
    to him to test.)

    Andy Coggan
     
  11. Andy Coggan

    Andy Coggan Guest

    "Michael Hoyt" <[email protected]> wrote in message news:[email protected]...
    > That's a picture of a 350. The 420 tapers to as fine an edge as you'll see
    on
    > any wheel. I've seen them in the flesh <g>.

    I was referring to the pictures of the 420 you'll find at the bottom of that page, which appear to
    show the same squared-off inner circumference as found on the 350 rim (esp. the uncut rim shown on
    the left). However, if the inner circumference is indeed rounded and not flat (and also not too
    "pointy"), then the aerodynamics will be better than I first predicted.

    Andy Coggan

    > Andy Coggan wrote:
    >
    > > "VeloCat" <[email protected]> wrote in message news:[email protected]...
    > > > Andy Coggan wrote:
    > > > > Based on its Ksyrium-like profile, I suspect that the AC 420
    wouldn't be
    > > > > much more aerodynamic than a standard box-section rim.
    > > > >
    > > >
    > > > The Ksyrium rims are 24mm deep in cross section. The AC420s are 34mm. Why don't you think
    > > > there would be a difference? The Zipp 303s are
    > > > 40mm. I would say the AC420 is more Zipp-like than Ksyrium-like.
    > >
    > > Take a closer look:
    > >
    > > http://www.amclassic.com/Rims.html
    > >
    > > Given the squared-off inner circumference, I can't see the extra 10 mm
    of
    > > depth being all that helpful.
    > >
    > > Andy Coggan
     
  12. Kevin

    Kevin Guest

    It sucks that AC won't offer the 420 rim for sale, they only offer it as a complete wheel. Are there
    any other rims on the market, that have a similar depth, that you can buy just the rims alone (aside
    from carbon rims from zipp)?
     
  13. Velocat

    Velocat Guest

    Andy Coggan wrote:

    > I was referring to the pictures of the 420 you'll find at the bottom of that page, which appear to
    > show the same squared-off inner circumference as found on the 350 rim (esp. the uncut rim shown on
    > the left). However, if the inner circumference is indeed rounded and not flat (and also not too
    > "pointy"), then the aerodynamics will be better than I first predicted.
    >
    > Andy Coggan

    I have my new AC420 in my hand and can say that the inner circumference is somewhat rounded,
    definitely not flat. The cross section at

    http://www.amclassic.com/Rims.html

    is a pretty good representation. The outside surface of the rim along the inner circumference is
    rounded, the "inside" (inside the rim itself) surface around the inner circumference appears flat in
    the cross section. I believe this is visibile on the page sited above.
     
  14. Andy Coggan

    Andy Coggan Guest

    The Velocity Deep V is 30 mm deep, has a nicely rounded inner circumference, and pretty good
    aerodynamics all things considered (based on wind tunnel tests of the original Rolf wheel, which
    used the same rim). Compared to the 420, though, it isn't quite as deep (although again, just
    based on the pics, I don't think the AC would necessarily generate any less drag), and it is about
    100 g heavier.

    Andy Coggan

    "Kevin" <[email protected]> wrote in message
    news:[email protected]...
    > It sucks that AC won't offer the 420 rim for sale, they only offer it as a complete wheel. Are
    > there any other rims on the market, that have a similar depth, that you can buy just the rims
    > alone (aside from carbon rims from zipp)?
     
  15. "Andy Coggan" <[email protected]> wrote in message
    news:[email protected]...
    >(Kraig Willet should be headed to the Texas A&M wind tunnel any day now...would be nice if we get
    >an AC 420 wheel to him to test.)

    I head out Sunday. No such luck in this case though - I won't be testing the AC420.

    The trailing edge, and rim curvature near it, does matter. I can remember testing a 47 mm deep rim
    that was so inefficiently shaped that it performed equivalently to a 25 mm deep rim.

    For the most part, though, (and I hate to generalize like this) rim depth is the primary contributor
    to the reduction in body axis drag.

    Anyone wishing to read more on the topic can email me privately for the Greenwell paper (a wheel
    aerodynamics article that appeared in a scholarly journal).

    --
    ==================
    Kraig Willett www.biketechreview.com
    ==================
     
  16. Andy Coggan wrote:
    > The Velocity Deep V is 30 mm deep, has a nicely rounded inner circumference, and pretty good
    > aerodynamics all things considered (based on wind tunnel tests of the original Rolf wheel, which
    > used the same rim). Compared to the 420, though, it isn't quite as deep (although again, just
    > based on the pics, I don't think the AC would necessarily generate any less drag), and it is about
    > 100 g heavier.
    >
    > Andy Coggan

    Actually, I believe the original Rolf Wheels used the Araya SuperAero rim, which was also 30mm deep
    but had a more rounded profile than the Velocity Deep V rim (and was a little lighter as well).

    Mark McMaster [email protected]

    >
    > "Kevin" <[email protected]> wrote in message
    > news:[email protected]...
    >
    >>It sucks that AC won't offer the 420 rim for sale, they only offer it as a complete wheel. Are
    >>there any other rims on the market, that have a similar depth, that you can buy just the rims
    >>alone (aside from carbon rims from zipp)?
    >>
    >
     
  17. Andy Coggan

    Andy Coggan Guest

    "Kraig Willett" <[email protected]> wrote in message
    news:[email protected]...
    > "Andy Coggan" <[email protected]> wrote in message
    > news:[email protected]...
    > >(Kraig Willet should be headed to the Texas A&M wind tunnel any day now...would be nice if we
    > >get an AC
    420
    > > wheel to him to test.)
    >
    > I head out Sunday.

    Have fun! (And make sure you try that burrito place on the other side of campus.)

    > No such luck in this case though - I won't be testing the AC420.

    That's too bad - if my guess proved incorrect and they were better aerodynamically than I expect,
    then I would probably buy a set.

    > The trailing edge, and rim curvature near it, does matter. I can remember testing a 47 mm deep rim
    > that was so inefficiently shaped that it
    performed
    > equivalently to a 25 mm deep rim.

    Would that have been a LEW wheel perhaps?

    > For the most part, though, (and I hate to generalize like this) rim depth is the primary
    > contributor to the reduction in body axis drag.
    >
    > Anyone wishing to read more on the topic can email me privately for the Greenwell paper (a wheel
    > aerodynamics article that appeared in a scholarly journal).

    The Greenwell paper is getting a bit dated by now...maybe you should try writing up your results and
    submitting them to a journal.

    Andy Coggan
     
  18. Amit

    Amit Guest

    "Andy Coggan" <[email protected]> wrote in message
    news:<%[email protected]>...
    > The Velocity Deep V is 30 mm deep, has a nicely rounded inner circumference, and pretty good
    > aerodynamics all things considered (based on wind tunnel tests of the original Rolf wheel, which
    > used the same rim). Compared to the 420, though, it isn't quite as deep (although again, just
    > based on the pics, I don't think the AC would necessarily generate any less drag), and it is about
    > 100 g heavier.
    >

    Andy,

    The AC420 rim is rounded at the leading (or inner) edge, similar to the Deep V. The AC420 wheels are
    pretty similar to Shamals.

    -Amit
     
  19. Andy Coggan

    Andy Coggan Guest

    "Mark McMaster" <[email protected]> wrote in message news:[email protected]...
    > Andy Coggan wrote:
    > > The Velocity Deep V is 30 mm deep, has a nicely rounded inner
    circumference,
    > > and pretty good aerodynamics all things considered (based on wind tunnel tests of the original
    > > Rolf wheel, which used the same rim). Compared to
    the
    > > 420, though, it isn't quite as deep (although again, just based on the
    pics,
    > > I don't think the AC would necessarily generate any less drag), and it
    is
    > > about 100 g heavier.
    > >
    > > Andy Coggan
    >
    > Actually, I believe the original Rolf Wheels used the Araya SuperAero rim, which was also
    > 30mm deep but had a more rounded profile than the Velocity Deep V rim (and was a little
    > lighter as well).

    Now that you mention it, I believe you are right (as it was partially the thinness of the Araya rim
    that led to lumpiness problems with the original Rolfs). Looking at the published cross-sections,
    though, I couldn't tell a difference between the Araya and the Deep V, which is why I went with the
    latter for that set of "do it all" wheels I built a few years ago.

    Andy Coggan
     
  20. Andy Coggan

    Andy Coggan Guest

    "Amit" <[email protected]> wrote in message
    news:[email protected]...
    > "Andy Coggan" <[email protected]> wrote in message
    news:<%[email protected]>...
    > > The Velocity Deep V is 30 mm deep, has a nicely rounded inner
    circumference,
    > > and pretty good aerodynamics all things considered (based on wind tunnel tests of the original
    > > Rolf wheel, which used the same rim). Compared to
    the
    > > 420, though, it isn't quite as deep (although again, just based on the
    pics,
    > > I don't think the AC would necessarily generate any less drag), and it
    is
    > > about 100 g heavier.
    > >
    >
    > Andy,
    >
    > The AC420 rim is rounded at the leading (or inner) edge, similar to the Deep V. The AC420 wheels
    > are pretty similar to Shamals.

    So now I'm really confused! The picture of the uncut rim makes it look rather "flat faced" (an
    optical illusion, perhaps?), the picture of the cut rim looks a bit more rounded as you describe,
    but then you compare the wheels to Shamals, which actually have a very sharp, or V-shaped, inner
    circumference. Maybe the latter comparison is just in terms of rim material and depth?

    Guess I'm going to have keep my eyes out for an AC420 in real life...

    Andy Coggan
     
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