Can someone clarify the Rivendell frame sizing article for me?

Discussion in 'Cycling Equipment' started by Doublej, Jun 22, 2003.

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  1. Doublej

    Doublej Guest

    I get the part about measuring to your pubic bone but then it gets vague. It looks like there is a
    rule of thumb subtraction to get from pubic bone height to saddle height. Specifically 10cm is used
    in the article. Is this correct?

    Then there appears to be second rule of thumb subtraction to get from saddle height to frame size.
    In the example 10 cm is used.

    Pubic bone (85) - Rule of Thumb A (10) = Saddle Height (75) Saddle Height (75) - Rule of Thumb B
    (15) = Frame Size (60)

    Do I have this correct?

    I understand tailoring individul differences in one's arm length with a stem but what about
    difference in the length between the upper and lower part of one's leg? Does this get tuned by the
    front/back saddle position?

    When all is said and done how difference will will 1-2 cm make in the comfort of a bike?

    http://www.rivendellbicycles.com/html/bikes_framesize.html
     
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  2. Andresmuro

    Andresmuro Guest

    I would ask Grant Petersen, owner of rivendell. He'll tell you if this is correct. Anyone at
    rivendell will gladly talk to you. they are all nice guys. Plus, if they are about to sell you a
    $2,000 frame, I am sure that they"ll be extra nice.

    Andres
     
  3. Richard Ney

    Richard Ney Guest

    Doublej writes:

    > I get the part about measuring to your pubic bone but then it gets vague. It looks like there is a
    > rule of thumb subtraction to get from pubic bone height to saddle height. Specifically 10cm is
    > used in the article. Is this correct?
    >
    > Then there appears to be second rule of thumb subtraction to get from saddle height to frame size.
    > In the example 10 cm is used.
    >
    > Pubic bone (85) - Rule of Thumb A (10) = Saddle Height (75) Saddle Height (75) - Rule of Thumb B
    > (15) = Frame Size (60)
    >
    > Do I have this correct?
    >
    > I understand tailoring individul differences in one's arm length with a stem but what about
    > difference in the length between the upper and lower part of one's leg? Does this get tuned by the
    > front/back saddle position?
    >
    > When all is said and done how difference will will 1-2 cm make in the comfort of a bike?
    >
    >
    > http://www.rivendellbicycles.com/html/bikes_framesize.html

    What does Grant/Rivendell have to say about all this?
     
  4. A shy person wrote:
    > I get the part about measuring to your pubic bone but then it gets vague. It looks like there is a
    > rule of thumb subtraction to get from pubic bone height to saddle height. Specifically 10cm is
    > used in the article. Is this correct?
    >
    > Then there appears to be second rule of thumb subtraction to get from saddle height to frame size.
    > In the example 10 cm is used.
    >
    > Pubic bone (85) - Rule of Thumb A (10) = Saddle Height (75) Saddle Height (75) - Rule of Thumb B
    > (15) = Frame Size (60)
    >
    > Do I have this correct?
    >
    > I understand tailoring individul differences in one's arm length with a stem but what about
    > difference in the length between the upper and lower part of one's leg? Does this get tuned by the
    > front/back saddle position?

    I'm a big fan of Grant Petersen, but we don't look at frame fitting from quite the same point of
    view. For my take on it, see:

    http://sheldonbrown.com/frame-sizing.html

    > When all is said and done how difference will will 1-2 cm make in the comfort of a bike?

    The seat tube length as such has NO effect on the comfort of a bike!

    Top tube length is much more important, as is seat tube angle (though there tends to be rather less
    variety in seat tube angles for current frames.)

    Head angle and chainstay length also have some relevance, but not nearly as much as top-tube length.

    You can't size a bike well just by looking at leg length.

    Sheldon "UBM" Brown +-------------------------------+
    | It's never too late to have | a happy childhood | --Jacek Rudowski |
    +-------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX
    617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide http://captainbike.com
    http://sheldonbrown.com
     
  5. In article <[email protected]>,
    Sheldon Brown <[email protected]> wrote:

    > A shy person wrote:
    > > I get the part about measuring to your pubic bone but then it gets vague. It looks like there is
    > > a rule of thumb subtraction to get from pubic bone height to saddle height. Specifically 10cm is
    > > used in the article. Is this correct?

    > > I understand tailoring individul differences in one's arm length with a stem but what about
    > > difference in the length between the upper and lower part of one's leg? Does this get tuned by
    > > the front/back saddle position?

    > I'm a big fan of Grant Petersen, but we don't look at frame fitting from quite the same point of
    > view. For my take on it, see:
    >
    > http://sheldonbrown.com/frame-sizing.html
    >
    > > When all is said and done how difference will will 1-2 cm make in the comfort of a bike?
    >
    > The seat tube length as such has NO effect on the comfort of a bike!
    >
    > Top tube length is much more important, as is seat tube angle (though there tends to be rather
    > less variety in seat tube angles for current frames.)

    Your excellent fit article makes this point in a roundabout way, but I think it is non-obvious
    enough to mention:

    Bicycle fit is primarily a matter of getting your butt, hands, and feet into a triangle of the
    correct size and shape for your body and riding. Any frame that can be adjusted to fit this
    triangle, within reason, will work. About the only exception is Mark Hickey's satirical "One size"
    bicycle, with a 300 mm steering stem for Jobst-sized cyclists. At some point stem length messes with
    the ability to steer the bike well.

    Of course, Mark also once proposed a 53/23 front double with a 11-34 2v rear cassette for an ideal
    range of gearing...

    There are second-order considerations like Q-factor, crank length, bar width and shape, and seat
    type that make you comfortable on the bicycle, but aren't really in the purview of what we think of
    as frame fit. They're more "component fit" considerations.

    > Head angle and chainstay length also have some relevance, but not nearly as much as
    > top-tube length.
    >
    > You can't size a bike well just by looking at leg length.

    --
    Ryan Cousineau, [email protected] http://www.sfu.ca/~rcousine President, Fabrizio Mazzoleni Fan Club
     
  6. Tim McNamara

    Tim McNamara Guest

    In article <[email protected]>,
    "Doublej" <[email protected]> wrote:

    > I get the part about measuring to your pubic bone but then it gets vague. It looks like there is a
    > rule of thumb subtraction to get from pubic bone height to saddle height. Specifically 10cm is
    > used in the article. Is this correct?
    >
    > Then there appears to be second rule of thumb subtraction to get from saddle height to frame size.
    > In the example 10 cm is used.
    >
    > Pubic bone (85) - Rule of Thumb A (10) = Saddle Height (75) Saddle Height (75) - Rule of Thumb B
    > (15) = Frame Size (60)
    >
    > Do I have this correct?

    There are dozens of ways to determine saddle height, all of which work more or less well. If
    measuring from the center of the BB to the top of the saddle, you can multiply floor-to-pubic bone
    height by .885 to determine saddle height; or you can measure from saddle to top of pedal when the
    pedal is as far from the saddle as possible and set the saddle height at 109% of your pants inseam;
    or you can just raise the saddle until your hips start to rock when you pedal and lower it back down
    until they stop rocking; or...

    You get the point. These are all rules of thumb. Grant uses rules of thumb similar to what Mondonico
    uses. Grant also acknowledges that these are only rules of thumb and not absolutes. Since the vast
    majority of people are normally proportioned, most normally proportioned bikes will be within the
    range of adjustability to get them to fit for most riders.

    There is a lot of baloney and mystique about bike fit used to justify custom built frames with tube
    lengths determined down to the millimeter- or so the customer is led to believe. Few of us cannot be
    fit equally well by an off-the-rack bike in the appropriate seat tube length.

    > When all is said and done how difference will will 1-2 cm make in the comfort of a bike?
    >
    > http://www.rivendellbicycles.com/html/bikes_framesize.html

    Grant's point is to put riders on a frame big enough to let the handlebars be more or less level
    with the saddle. He'd probably put me on a frame 5-6 cm larger than most racing-oriented bike shops,
    for example. I am 6'4" with a 36.2" floor to pubic bone measurement (92
    cm). Most bike shops would put me on a 60 to 61 cm frame (not coincidentally, that's the largest
    frame many bike manufacturers make), which would leave me with the bars too low to be comfortable
    on the long rides I prefer. Grant would put me on a 65 or 66 cm frame, which psychologically is
    too big for my tastes. I prefer about a 63 to 64 cm frame, ideally, although most of my bikes are
    in the 61 cm range because that's what was available. Thus I have stems with really long quills
    or a fairly steep upslope.
     
  7. Mark Hickey

    Mark Hickey Guest

    Ryan Cousineau <[email protected]> wrote:

    >About the only exception is Mark Hickey's satirical "One size" bicycle, with a 300 mm steering stem
    >for Jobst-sized cyclists. At some point stem length messes with the ability to steer the bike well.
    >
    >Of course, Mark also once proposed a 53/23 front double with a 11-34 2v rear cassette for an ideal
    >range of gearing...

    Hey, if you guys are actually gonna pay attention, I'm gonna have to start spewing so much nonsense!

    Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
  8. In article <[email protected]>, Mark Hickey <[email protected]> wrote:

    > Ryan Cousineau <[email protected]> wrote:
    >
    > >About the only exception is Mark Hickey's satirical "One size" bicycle, with a 300 mm steering
    > >stem for Jobst-sized cyclists. At some point stem length messes with the ability to steer the
    > >bike well.
    > >
    > >Of course, Mark also once proposed a 53/23 front double with a 11-34 2v rear cassette for an
    > >ideal range of gearing...
    >
    > Hey, if you guys are actually gonna pay attention, I'm gonna have to start spewing so much
    > nonsense!
    >
    > Mark Hickey Habanero Cycles

    Well, it's a special case for me, Mark: I'm a big fan of yours. Alas, the duties of the Fabrizio
    Mazzoleni Fan Club (membership: 2 and growing) are a sufficient commitment that I can take on no
    other fan clubs at this time.

    --
    Ryan Cousineau, [email protected] http://www.sfu.ca/~rcousine President, Fabrizio Mazzoleni Fan Club
     
  9. Double-<< I get the part about measuring to your pubic bone but then it gets vague. It looks like
    there is a rule of thumb subtraction to get from pubic bone height to saddle height. Specifically
    10cm is used in the article. Is this correct? >><BR><BR> \ There are really no 'rules of thumb', but
    'opinions of thumb' with any, non hands on, fitting formula. They are a great place to start but
    humans, with their own requirements for a frameset, make this really tough. I would see if there is
    a local bike fit person around, with good knowledge and expertise, to do the fitting for you.

    << Pubic bone (85) - Rule of Thumb A (10) = Saddle Height (75) Saddle Height (75) - Rule of Thumb B
    (15) = Frame Size (60)

    Do I have this correct? >><BR><BR>

    Probably with the formula but this doesn't seem to take into account seat tube angle or top tube
    length. A 'size' of 60cm means very little, particulalry when one size '60' can be drastically
    different from another size '60'..

    << I understand tailoring individul differences in one's arm length with a stem but what about
    difference in the length between the upper and lower part of one's leg? Does this get tuned by the
    front/back saddle position? >><BR><BR>

    Bing, bing, bing, we have a winner....

    It can 'tuned' by fore/aft movememnt, to an extent. If your femurs are very long, may not be able to
    get the saddle back far enough, for instance...if the seat tube isn't slack enough.

    << When all is said and done how difference will will 1-2 cm make in the comfort of a bike?
    >><BR><BR>

    See above can make a lot of difference. Having to use a really short or really long stem can make a
    difference.

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
     
  10. Rick Warner

    Rick Warner Guest

    "Doublej" <[email protected]> wrote in message news:<[email protected]>...

    AS others have said, call and talk to Grant, or Mark, or Bhima. They are nice guys. Grant measured a
    friend on Saturday, their PBH was close to yours, and Grant said 59 cm but try the 61 cm, too. He
    does not seem to be too stuck on the formula, just gets you close then the rest is up to you. If you
    have the Rivendell Reader #29 (most recent) the last inside page profiles a buyer who got a Romulus
    but opted for a size smaller than Grant recommended, but Grant said he was OK with that. His big
    thing in bike fit is to get the handlebars higher than most manufacturers and shops recommend, at
    least up to level with the seat. He points out that effective top tube length gets shorter as you
    move the stem up (due to angle of the head tube), so real top tube length of a given frame does not
    provide the most relevant information; he demonstrated a 1.5 cm difference on one frame between
    maximum and minimum insertion of the quill for us when my friend mentioned the issue of top tube
    length. Of course the best choice would be to ride a Riv, but unless you live in the SF Bay area or
    near one of the few dealers that carry Riv's (a very small number) then you are out of luck.

    - rick warner
     
  11. Rick Warner

    Rick Warner Guest

    Tim McNamara <[email protected]> wrote in message
    news:<[email protected]>...

    > Grant's point is to put riders on a frame big enough to let the handlebars be more or less level
    > with the saddle. He'd probably put me on a frame 5-6 cm larger than most racing-oriented bike
    > shops, for example. I am 6'4" with a 36.2" floor to pubic bone measurement (92
    > cm). Most bike shops would put me on a 60 to 61 cm frame (not coincidentally, that's the largest
    > frame many bike manufacturers make), which would leave me with the bars too low to be
    > comfortable on the long rides I prefer. Grant would put me on a 65 or 66 cm frame, which
    > psychologically is too big for my tastes. I prefer about a 63 to 64 cm frame, ideally, although
    > most of my bikes are in the 61 cm range because that's what was available. Thus I have stems
    > with really long quills or a fairly steep upslope.

    Grant will try to put you on a frame where the bars are at *least* level with the seat, preferably a
    bit above. And you would go on either their 65 cm or 68 cm frame in the stock frames/bikes. Due to
    the low bottom bracket, a 65 on one of their frames will have a lower standover than most 63 cm
    frames. The GM of a local LBS is 6'5" and rides a 68 cm Rambo; seems to fit him nicely but put that
    bike next to any other and it looks monstrously tall. BTW, the tall frames have sure evoked a lot of
    interest in this area; I see a lot of folks test riding the Redwood's and have watched a number fly
    out the door of the LBS with new owners - all in the past couple of weeks.

    - rick warner
     
  12. Robin Hubert

    Robin Hubert Guest

    "Qui si parla Campagnolo" <[email protected]> wrote in message
    news:[email protected]...
    > Double-<< I get the part about measuring to your pubic bone but then it
    gets
    > vague. It looks like there is a rule of thumb subtraction to get from pubic bone height to saddle
    > height. Specifically 10cm is used in the article. Is this correct? >><BR><BR> \ There are really
    > no 'rules of thumb', but 'opinions of thumb' with any,
    non
    > hands on, fitting formula. They are a great place to start but humans,
    with
    > their own requirements for a frameset, make this really tough. I would see
    if
    > there is a local bike fit person around, with good knowledge and
    expertise, to
    > do the fitting for you.
    >
    > << Pubic bone (85) - Rule of Thumb A (10) = Saddle Height (75) Saddle Height (75) - Rule of Thumb
    > B (15) = Frame Size (60)
    >
    > Do I have this correct? >><BR><BR>
    >
    > Probably with the formula but this doesn't seem to take into account seat
    tube
    > angle or top tube length. A 'size' of 60cm means very little, particulalry
    when
    > one size '60' can be drastically different from another size '60'..

    I hear this all the time but I don't see "drastic" differences between makers. I'd say most frames
    you run across are fairly similar in this regard, with very rare outliers.

    >
    > << I understand tailoring individul differences in one's arm length with a
    stem
    > but what about difference in the length between the upper and lower part
    of
    > one's leg? Does this get tuned by the front/back saddle position?
    >><BR><BR>
    >
    >
    > Bing, bing, bing, we have a winner....
    >
    > It can 'tuned' by fore/aft movememnt, to an extent. If your femurs are
    very
    > long, may not be able to get the saddle back far enough, for instance...if
    the
    > seat tube isn't slack enough.
    >
    > << When all is said and done how difference will will 1-2 cm make in the comfort of a bike?
    > >><BR><BR>
    >
    > See above can make a lot of difference. Having to use a really short or
    really
    > long stem can make a difference.
    >

    --
    Robin Hubert <[email protected]
     
  13. Mark Hickey

    Mark Hickey Guest

    Ryan Cousineau <[email protected]> wrote:

    > Mark Hickey <[email protected]> wrote:
    >
    >> Ryan Cousineau <[email protected]> wrote:

    >> >Of course, Mark also once proposed a 53/23 front double with a 11-34 2v rear cassette for an
    >> >ideal range of gearing...

    >> Hey, if you guys are actually gonna pay attention, I'm gonna have to start spewing so much
    >> nonsense!

    >Well, it's a special case for me, Mark: I'm a big fan of yours. Alas, the duties of the Fabrizio
    >Mazzoleni Fan Club (membership: 2 and growing) are a sufficient commitment that I can take on no
    >other fan clubs at this time.

    I should just sign up for the Fabrizio Mazzoleni Fan Club myownself. I try to emulate him every way
    I can, but know I'll never reach is deity-like status as long as I even own a MTB.

    Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
  14. Tim McNamara

    Tim McNamara Guest

    In article <[email protected]>, [email protected] (Rick
    Warner) wrote:

    > AS others have said, call and talk to Grant, or Mark, or Bhima. They are nice guys. Grant measured
    > a friend on Saturday, their PBH was close to yours, and Grant said 59 cm but try the 61 cm, too.
    > He does not seem to be too stuck on the formula, just gets you close then the rest is up to you.
    > If you have the Rivendell Reader #29 (most recent) the last inside page profiles a buyer who got a
    > Romulus but opted for a size smaller than Grant recommended, but Grant said he was OK with that.

    Well, the bike is somewhat adjustable and the rider is somewhat adaptable. And Grant is smart enough
    not to argue with customers unless something is way out of line.
     
  15. Tim McNamara

    Tim McNamara Guest

    In article <[email protected]>, [email protected] (Rick
    Warner) wrote:

    > Tim McNamara <[email protected]> wrote in message
    > news:<[email protected]>...

    <snip>

    > Grant will try to put you on a frame where the bars are at *least* level with the seat, preferably
    > a bit above. And you would go on either their 65 cm or 68 cm frame in the stock frames/bikes. Due
    > to the low bottom bracket, a 65 on one of their frames will have a lower standover than most 63 cm
    > frames. The GM of a local LBS is 6'5" and rides a 68 cm Rambo; seems to fit him nicely but put
    > that bike next to any other and it looks monstrously tall. BTW, the tall frames have sure evoked a
    > lot of interest in this area; I see a lot of folks test riding the Redwood's and have watched a
    > number fly out the door of the LBS with new owners - all in the past couple of weeks.

    Well, I think that Grant is on to something by deliberately catering to bike users and making bikes
    comfortable and accessible. Rivendell is less rarified than it was 5 years ago, more down to earth
    and in touch with people and less focused on bike weenies like me.

    You're right, Grant would probably try to put me on at least a 65 and I'd be hard to convince since
    I don't want the bars that high (I like them just a smidge below the saddle, about 2-3 cm). Hah! My
    old Schwinn Continental (ca. 1973 or 74, stolen in 1976) was a 26" frame (66 cm) and I could barely
    clear the top tube when standing- but Grant's BBs are a lot lower.

    My Rivendell is one of the nicest riding bikes I've ever been on, even if it really is too small.
    Second only to my Ritchey, which is truly superb.
     
  16. In article <[email protected]>, Mark Hickey <[email protected]> wrote:

    > Ryan Cousineau <[email protected]> wrote:

    > I should just sign up for the Fabrizio Mazzoleni Fan Club myownself. I try to emulate him every
    > way I can, but know I'll never reach is deity-like status as long as I even own a MTB.

    We all have to start somewhere. Perhaps you could put drop bars on it, like John Tomac once did, and
    slowly transition it into a 'cross bike.

    --
    Ryan Cousineau, [email protected] http://www.sfu.ca/~rcousine President, Fabrizio Mazzoleni Fan Club
     
  17. Mark Hickey

    Mark Hickey Guest

    Ryan Cousineau <[email protected]> wrote:

    >In article <[email protected]>, Mark Hickey <[email protected]> wrote:
    >
    >> Ryan Cousineau <[email protected]> wrote:
    >
    >> I should just sign up for the Fabrizio Mazzoleni Fan Club myownself. I try to emulate him every
    >> way I can, but know I'll never reach is deity-like status as long as I even own a MTB.
    >
    >We all have to start somewhere. Perhaps you could put drop bars on it, like John Tomac once did,
    >and slowly transition it into a 'cross bike.

    Would I get more points if I made it a fixie while I was converting it? I would think that Fab has
    to be conflicted by John Tomac though. Sure the guy was a hard core MTBer, but he was also the
    national crit

    useful.

    Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
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