Cycling Equipment · Public discussion

are my femurs short?

Started by Kbh · · Last activity · 35 posts · 3,337 views

Thread navigation

Jump through the discussion

Go to the original post, the replies on this page, or the latest preserved contribution.

Thread details

What we know about this thread

Original section
Cycling Equipment
Published
1 May 2003
Last activity
7 May 2003
Original author
Kbh
Posts
35
Discussion status
Public discussion
Total views
3,337
Views / 30 days
0

The navigation and discussion metadata provide context. Posts remain in their original chronological order.

Showing posts 1–20 of 35
Posts remain in their original chronological order.

Text size
  1. This is a continuation of my riding posture thread from below:

    Put my bike on the trainer to do a self fitting, using my plumb bob I verified that I was about 1.5"
    - 2" behind KOPS. My bike has a 73 degree seat tube angle, and I'm using a seatpost with no setback
    and the saddle rails in the middle. My saddle height is 79 which results in a setback of
    23.1 cm. Only by putting the saddle almost as far forward as it can go on the rails can I get near
    KOPS. I'm going to try this for a while. I can't fathom the need for a saddle with setback, or a
    bike with a shallower seat tube angle.

    Is this setup unusual? Short femurs?

  2. KBH at [email hidden] wrote on 5/1/03 1:14 PM:

    Quoted message said:

    This is a continuation of my riding posture thread from below:

    Put my bike on the trainer to do a self fitting, using my plumb bob I verified that I was about
    1.5" - 2" behind KOPS. My bike has a 73 degree seat tube angle, and I'm using a seatpost with no
    setback and the saddle rails in the middle. My saddle height is 79 which results in a setback of
    23.1 cm. Only by putting the saddle almost as far forward as it can go on the rails can I get near
    KOPS. I'm going to try this for a while. I can't fathom the need for a saddle with setback, or
    a bike with a shallower seat tube angle.

    Is this setup unusual? Short femurs?

    Before you follow that too far, read Keith Bontrager's article on the "Myth of KOPS" -

    (of course, there's a version on sheldon's site) sheldonbrown.comkops.html

  3. I realize that KOPS is nothing but a reference point, and I was only referring to it as such. My
    desire to try KOPS actually has to do with back problems, and general experimentation with bike fit.
    It just seems odd to me that I can only get to this common rider position with a 73 degree seat
    tube, saddle forward on rails , and no seatpost setback.

    "Jim Edgar" <[email hidden]> wrote in message "]news:[email hidden]...

    Quoted message said:

    KBH at [email hidden] wrote on 5/1/03 1:14 PM:

    Quoted message said:

    This is a continuation of my riding posture thread from below:

    Put my bike on the trainer to do a self fitting, using my plumb bob I verified that I was about
    1.5" - 2" behind KOPS. My bike has a 73


    degree

    Quoted message said:
    Quoted message said:

    seat tube angle, and I'm using a seatpost with no setback and the saddle rails in the middle. My
    saddle height is 79 which results in a setback


    of

    Quoted message said:
    Quoted message said:

    23.1 cm. Only by putting the saddle almost as far forward as it can go


    on

    Quoted message said:
    Quoted message said:

    the rails can I get near KOPS. I'm going to try this for a while. I


    can't

    Quoted message said:
    Quoted message said:

    fathom the need for a saddle with setback, or a bike with a shallower


    seat

    Quoted message said:
    Quoted message said:

    tube angle.

    Is this setup unusual? Short femurs?

    Before you follow that too far, read Keith Bontrager's article on the


    "Myth

    Quoted message said:

    of KOPS" -

    (of course, there's a version on sheldon's site) sheldonbrown.comkops.html

  4. "Jim Edgar" <[email hidden]> wrote in message "]news:[email hidden]...

    Quoted message said:

    KBH at [email hidden] wrote on 5/1/03 1:14 PM:

    Quoted message said:

    This is a continuation of my riding posture thread from below:

    Put my bike on the trainer to do a self fitting, using my plumb bob I verified that I was about
    1.5" - 2" behind KOPS. My bike has a 73


    degree

    Quoted message said:
    Quoted message said:

    seat tube angle, and I'm using a seatpost with no setback and the saddle rails in the middle. My
    saddle height is 79 which results in a setback


    of

    Quoted message said:
    Quoted message said:

    23.1 cm. Only by putting the saddle almost as far forward as it can go


    on

    Quoted message said:
    Quoted message said:

    the rails can I get near KOPS. I'm going to try this for a while. I


    can't

    Quoted message said:
    Quoted message said:

    fathom the need for a saddle with setback, or a bike with a shallower


    seat

    Quoted message said:
    Quoted message said:

    tube angle.

    Is this setup unusual? Short femurs?

    Before you follow that too far, read Keith Bontrager's article on the


    "Myth

    Quoted message said:

    of KOPS" -

    (of course, there's a version on sheldon's site) sheldonbrown.comkops.html

    KOPS is a guideline, but too far off either way and you run into biomechanical issues with the pedal
    stroke. Too far back and you don't use the hamstrings as much, too far forward and you loose some of
    the butt muscles effectiveness.

    Have you ever had anyone fit you to your bike? I see lots and lots of people that are riding bikes
    that "fit" according to them, but when really fit gain several miles per hour with no additional
    effort. I would recommend that you start there.

    "Self-fitting" properly is almost impossible. You can't really look at yourself without moving out
    of the proper riding position. (unless you're using a video camera and playing back the tape later)

    Without seeing you riding, its hard for us on the 'net to diagnose your fit. We're just taking stabs
    in the dark. Go have a fit done, let a local expert help you determine your optimal position.

    Mike

  5. I hear ya about the fitting (speaking to the many r.b.t er's recommending the same), but I'm of the
    opinion that individual's bodies (or maybe just mine) are too unique to really benefit from a single
    session. A fitting makes sense for the non-techie bicycle buyer, but I'm a geek and I'm fully
    capable of adjusting the three human/bicycle interface points and then seeing how my body responds.
    Unless the fitter wants to see me once a week for the next 3 months, its just not worth it.

    "Mike S." <mikeshaw2@coxDOTnet> wrote in message news:aUfsa.40$2R.31@fed1read07...

    Quoted message said:


    "Jim Edgar" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    KBH at [email hidden] wrote on 5/1/03 1:14 PM:

    Quoted message said:

    This is a continuation of my riding posture thread from below:

    Put my bike on the trainer to do a self fitting, using my plumb bob I verified that I was
    about 1.5" - 2" behind KOPS. My bike has a 73


    degree

    Quoted message said:
    Quoted message said:

    seat tube angle, and I'm using a seatpost with no setback and the


    saddle

    Quoted message said:
    Quoted message said:
    Quoted message said:

    rails in the middle. My saddle height is 79 which results in a setback


    of

    Quoted message said:
    Quoted message said:

    23.1 cm. Only by putting the saddle almost as far forward as it can go


    on

    Quoted message said:
    Quoted message said:

    the rails can I get near KOPS. I'm going to try this for a while. I


    can't

    Quoted message said:
    Quoted message said:

    fathom the need for a saddle with setback, or a bike with a shallower


    seat

    Quoted message said:
    Quoted message said:

    tube angle.

    Is this setup unusual? Short femurs?

    Before you follow that too far, read Keith Bontrager's article on the


    "Myth

    Quoted message said:

    of KOPS" -

    (of course, there's a version on sheldon's site) sheldonbrown.comkops.html

    KOPS is a guideline, but too far off either way and you run into biomechanical issues with the
    pedal stroke. Too far back and you don't use the hamstrings as much, too far forward and you loose
    some of the butt muscles effectiveness.

    Have you ever had anyone fit you to your bike? I see lots and lots of people that are riding bikes
    that "fit" according to them, but when really fit gain several miles per hour with no additional
    effort. I would recommend that you start there.

    "Self-fitting" properly is almost impossible. You can't really look at yourself without moving
    out of the proper riding position. (unless you're using a video camera and playing back the
    tape later)

    Without seeing you riding, its hard for us on the 'net to diagnose your


    fit.

    Quoted message said:

    We're just taking stabs in the dark. Go have a fit done, let a local


    expert

    Quoted message said:

    help you determine your optimal position.

    Mike

  6. KBH at [email hidden] wrote on 5/1/03 2:28 PM:

    Quoted message said:

    I hear ya about the fitting (speaking to the many r.b.t er's recommending the same), but I'm of
    the opinion that individual's bodies (or maybe just mine) are too unique to really benefit from
    a single session. A fitting makes sense for the non-techie bicycle buyer, but I'm a geek and I'm
    fully capable of adjusting the three human/bicycle interface points and then seeing how my body
    responds. Unless the fitter wants to see me once a week for the next 3 months, its just not
    worth it.


    A decent fitting session from a qualified person will tell you where you should ultimately position
    yourself - not just where you can go at that moment. The person doing the work should be certified
    or at least have considerable pedigree for proper fitting.

    A knowledgeable fitter should probably give you an indication of how long to take to move to a new
    position, so as not to injure or stress your bits. If you need to move an inch, you probably don't
    want to do that all in one fell swoop, and then go out and ride a century.

    I can't help but think your body will not respond particularly pleasantly to the 1.5 - 2" shift in
    position you describe in your post (below) - you might want to think about moving more gradually to
    that position.

    Quoted message said:
    Quoted message said:
    Quoted message said:

    > KBH at [email hidden] wrote on 5/1/03 1:14 PM:
    >
    > This is a continuation of my riding posture thread from below:
    >
    > Put my bike on the trainer to do a self fitting, using my plumb bob I verified that I was about
    > 1.5" - 2" behind KOPS. My bike has a 73 degree seat tube angle, and I'm using a seatpost with
    > no setback and the saddle rails in the middle. My saddle height is 79 which results in a
    > setback of
    > 23.1 cm. Only by putting the saddle almost as far forward as it can go on the rails can I get
    > near KOPS. I'm going to try this for a while. I can't fathom the need for a saddle with
    > setback, or a bike with a shallower seat tube angle.
    >
    > Is this setup unusual? Short femurs?

  7. RE/

    Quoted message said:

    I can't fathom the need for a saddle with setback, or a bike with a shallower seat tube angle.

    Is this setup unusual? Short femurs?

    Maybe it's a combinatin of the bike's dimensions and body proportions.

    I'm on the tall side (6'5"😉 and to get KOPS on my Ellsworth Isis I need a HellBent seatpost (2" of
    additional setback) and my Brooks B-17 set as far back as the rails will allow. And I could *still*
    use another half-inch...

    My shins don't seem proportionally short - if anything, it's the other way around.
    -----------------------
    PeteCresswell

  8. Quoted message said:

    I can't fathom the need for a saddle with setback, or a bike with a


    shallower seat

    Quoted message said:
    Quoted message said:

    tube angle.

    Is this setup unusual? Short femurs?

    Maybe it's a combinatin of the bike's dimensions and body proportions.

    I'm on the tall side (6'5"😉 and to get KOPS on my Ellsworth Isis I need a HellBent seatpost (2" of
    additional setback) and my Brooks B-17 set as far


    back

    Quoted message said:

    as the rails will allow. And I could *still* use another half-inch...

    My shins don't seem proportionally short - if anything, it's the other way around.

    Wow.

    I thought about that but the ONLY dimensions of the bike, excluding the seatpost/saddle, that
    determine KOPS are seat tube angle, saddle height, and crank length - that's it. So its gotta be the
    upper to lower leg ratio, not the absolute length of the femur.

  9. "KBH" <[email hidden]> wrote in message news

    Quoted message said:
    Quoted message said:

    I'm on the tall side (6'5"😉 and to get KOPS on my Ellsworth Isis I need a HellBent seatpost (2"
    of additional setback) and my Brooks B-17 set as far


    back

    Quoted message said:

    as the rails will allow. And I could *still* use another half-inch...

    My shins don't seem proportionally short - if anything, it's the other way around.

    Wow.

    I thought about that but the ONLY dimensions of the bike, excluding the seatpost/saddle, that
    determine KOPS are seat tube angle, saddle height, and crank length - that's it. So its gotta be
    the upper to lower leg ratio, not the absolute length of the femur.

    But this man is 6'5" so on standard cranks he will need to sit way back to get KOPS.

    Andrew Bradley

  10. Quoted message said:
    Quoted message said:
    Quoted message said:

    I'm on the tall side (6'5"😉 and to get KOPS on my Ellsworth Isis I


    need a

    Quoted message said:
    Quoted message said:
    Quoted message said:

    HellBent seatpost (2" of additional setback) and my Brooks B-17 set as


    far

    Quoted message said:
    Quoted message said:

    back

    Quoted message said:

    as the rails will allow. And I could *still* use another


    half-inch...

    Quoted message said:
    Quoted message said:
    Quoted message said:


    My shins don't seem proportionally short - if anything, it's the other


    way

    Quoted message said:
    Quoted message said:
    Quoted message said:

    around.

    Wow.

    I thought about that but the ONLY dimensions of the bike, excluding the seatpost/saddle, that
    determine KOPS are seat tube angle, saddle height,


    and

    Quoted message said:
    Quoted message said:

    crank length - that's it. So its gotta be the upper to lower leg ratio,


    not

    Quoted message said:
    Quoted message said:

    the absolute length of the femur.

    But this man is 6'5" so on standard cranks he will need to sit way back to


    get KOPS.

    Quoted message said:

    That argument would only be true if we all rode the same saddle height. Since he is tall, his saddle
    height will be larger, resulting in more "built-in" setback as a result of the seat tube angle.
    Assuming that the relationship between total pubic bone height and saddle height is roughly constant
    (rule of thumb is 0.883 x PBH), then this brings you back to the conclusion that weather you're 5'2"
    or 6'5", it is the ration of upper leg to lower leg that determines KOPS and therefore how much
    seatpost setback you may need and where the saddle may need to be on the rails.

  11. kbh-<< Put my bike on the trainer to do a self fitting, using my plumb bob I verified that I was
    about 1.5" - 2" behind KOPS. My bike has a 73 degree seat tube angle, and I'm using a seatpost with
    no setback and the saddle rails in the middle.

    Yes, I would say you would benefit from a frameset with a steeper seattube angle.

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 vecchios.comvecchios.com "Ruote convenzionali costruite eccezionalmente bene"

  12. I thougt 73 was on the steep side already, and that 74 starts to get you into tri bike territory? I
    wouldn't have guessed I was an outlier physically. I would love to see some stats of upper/lower leg
    length for people close to my height - although I don't think my friends would appreciate me
    measuring their legs.

    "Qui si parla Campagnolo" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    kbh-<< Put my bike on the trainer to do a self fitting, using my plumb bob


    I

    Quoted message said:

    verified that I was about 1.5" - 2" behind KOPS. My bike has a 73 degree seat tube angle, and I'm
    using a seatpost with no setback and the saddle rails in the middle.

    Yes, I would say you would benefit from a frameset with a steeper seattube angle.

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 vecchios.comvecchios.com "Ruote convenzionali costruite eccezionalmente bene"

  13. FWIW, Competitive Cyclist has added a decent fit calculator to their website. It's based on the
    Guimard/Lemond methodology with some of their own tweaks, and looks to work pretty well. The TT/Stem
    recommendations it gave me pretty much matched the ones from Lennard Zinn's basic fit calculator, as
    well as matching what I've arrived at as best for me over the years. Plus, it does take into account
    femur/tibia ratio and gives a saddle setback recommendation in addition to the usual Seat
    Height/ST/TT/Stem Length output of most fit systems.

    You might give it a try to see what it suggests for you.

    competitivecyclist.comcompetitivecyclist.com

    SB

    "KBH" <[email hidden]> wrote in message news:Ybusa.733301$S_4.757006@rwcrnsc53...

    Quoted message said:

    I thougt 73 was on the steep side already, and that 74 starts to get you into tri bike territory?
    I wouldn't have guessed I was an outlier physically. I would love to see some stats of upper/lower
    leg length for people close to my height - although I don't think my friends would appreciate me
    measuring their legs.

    "Qui si parla Campagnolo" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    kbh-<< Put my bike on the trainer to do a self fitting, using my plumb


    bob

    Quoted message said:

    I

    Quoted message said:

    verified that I was about 1.5" - 2" behind KOPS. My bike has a 73


    degree

    Quoted message said:
    Quoted message said:

    seat tube angle, and I'm using a seatpost with no setback and the saddle rails in the middle.

    Yes, I would say you would benefit from a frameset with a steeper


    seattube

    Quoted message said:
    Quoted message said:

    angle.

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 vecchios.comvecchios.com "Ruote convenzionali costruite eccezionalmente bene"

  14. Mike S.' mikeshaw2@coxDOTnet said:

    KOPS is a guideline, but too far off either way and you run into biomechanical issues with the
    pedal stroke. Too far back and you don't use the hamstrings as much, too far forward and you loose
    some of the butt muscles effectiveness.

    This all sounds familiar, but whats "muscle effectiveness" and where's the data on these
    "biomechanical issues" or explanation of them?

    Records are broken well forward of KOPS, people have won TDF KOM sitting well forward (though they
    may be behind KOPS on hills).

    Forget KOPS as being some kind of true "norm" when inching the saddle forward or back, your upper
    body and the muscles crossing the hip joint won't let you stray too far.

    Quoted message said:

    "Self-fitting" properly is almost impossible. You can't really look at yourself without moving
    out of the proper riding position. (unless you're using a video camera and playing back the
    tape later)

    Eyeballing for fine tuning isn't great either. When i had a 73 degree frame with saddle forward,
    they said "too far forward". On a 75 degree frame no one noticed anything untoward.

    Take away the seat-tube reference point and a rider can look nice over a range of fore aft
    positions.

    Andrew Bradley

  15. Thanks! This is exactly the type of reference I was looking for.

    "Steve Blankenship" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    FWIW, Competitive Cyclist has added a decent fit calculator to their website. It's based on the
    Guimard/Lemond methodology with some of their own tweaks, and looks to work pretty well. The
    TT/Stem recommendations it gave me pretty much matched the ones from Lennard Zinn's basic fit
    calculator, as well as matching what I've arrived at as best for me over


    the

    Quoted message said:

    years. Plus, it does take into account femur/tibia ratio and gives a


    saddle

    Quoted message said:

    setback recommendation in addition to the usual Seat Height/ST/TT/Stem Length output of most fit
    systems.

    You might give it a try to see what it suggests for you.

    competitivecyclist.comcompetitivecyclist.com

    SB

    "KBH" <[email hidden]> wrote in message news:Ybusa.733301$S_4.757006@rwcrnsc53...

    Quoted message said:

    I thougt 73 was on the steep side already, and that 74 starts to get you into tri bike
    territory? I wouldn't have guessed I was an outlier physically. I would love to see some stats
    of upper/lower leg length


    for

    Quoted message said:
    Quoted message said:

    people close to my height - although I don't think my friends would appreciate me measuring
    their legs.

    "Qui si parla Campagnolo" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    kbh-<< Put my bike on the trainer to do a self fitting, using my plumb


    bob

    Quoted message said:

    I

    Quoted message said:

    verified that I was about 1.5" - 2" behind KOPS. My bike has a 73


    degree

    Quoted message said:
    Quoted message said:

    seat tube angle, and I'm using a seatpost with no setback and the


    saddle

    Quoted message said:
    Quoted message said:
    Quoted message said:

    rails in the middle.

    Yes, I would say you would benefit from a frameset with a steeper


    seattube

    Quoted message said:
    Quoted message said:

    angle.

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 vecchios.comvecchios.com "Ruote convenzionali costruite eccezionalmente bene"



  16. KBH: This has always been a problem for me. I have short femurs, long torso, short arms. The ideal
    body not to do cycling. Good cyclists tend to have longer legs, shorter torso's and long arms. This
    is why you see them riding with small bikes and with the stem all the way down in pictures. They can
    put the seatpost all the way up, they need a smaller bike with a short top tube, and they can easily
    reach the handlebars with their long arms. There is an advantage in aerodynamics and in having
    proportionally more weight in the lower bodies than upper bodies.

    We all want to look like good cyclists, so we buy bikes designed for them, but our bodies do not
    fit. I had to look for a bike that wasn't too tall but had a long top tube, for a long time.
    American bikes are designed this way more than european bikes. While it solved my torso problem, I
    always felt that I was too far back in relation to the pedals. This has been a problem for me when
    ridding for a long time, or when I wanted to get aerodynamic for a long time, as in a triathlon. By
    being too far behind my pedals, I created a very acute angle between my back and my thighs, when my
    leg was on top of the circle. After a while, I would get pain on my lower back. I would have to
    dimount after 40 miles or so, to stretch. I am reasonably flexible and I swim a lot which helps, but
    I would still get a sore back.

    About a year ago I purchased a bike with a steeper seat angle of 76 degrees, a long top tube and
    farily short seat tube. It is perfect. I can ride forever, and my back does not hurt. I set my
    handlebar around the same height as my saddle and I can get pretty aerodynamic. Last year I rode a
    century and stayed on the aerobars for most of the ride. I was too lazy to get up and it felt really
    confortable staying aero. while the bike has similar dimensions of a triathlon bike, for my body
    type it fits well as a rode bike and rides great. Good luck,

    Andres

    "KBH" <[email hidden]> wrote in message news:<CPfsa.694355$L1.199115@sccrnsc02>...

    Quoted message said:

    I realize that KOPS is nothing but a reference point, and I was only referring to it as such. My
    desire to try KOPS actually has to do with back problems, and general experimentation with bike
    fit. It just seems odd to me that I can only get to this common rider position with a 73 degree
    seat tube, saddle forward on rails , and no seatpost setback.

    "Jim Edgar" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    KBH at [email hidden] wrote on 5/1/03 1:14 PM:

    Quoted message said:

    This is a continuation of my riding posture thread from below:

    Put my bike on the trainer to do a self fitting, using my plumb bob I verified that I was
    about 1.5" - 2" behind KOPS. My bike has a 73


    degree

    Quoted message said:
    Quoted message said:

    seat tube angle, and I'm using a seatpost with no setback and the saddle rails in the middle.
    My saddle height is 79 which results in a setback


    of

    Quoted message said:
    Quoted message said:

    23.1 cm. Only by putting the saddle almost as far forward as it can go


    on

    Quoted message said:
    Quoted message said:

    the rails can I get near KOPS. I'm going to try this for a while. I


    can't

    Quoted message said:
    Quoted message said:

    fathom the need for a saddle with setback, or a bike with a shallower


    seat

    Quoted message said:
    Quoted message said:

    tube angle.

    Is this setup unusual? Short femurs?

    Before you follow that too far, read Keith Bontrager's article on the


    "Myth

    Quoted message said:

    of KOPS" -

    (of course, there's a version on sheldon's site) sheldonbrown.comkops.html

  17. "Road Racing Technique and Training" by Bernard Hinault and Claude Genzling ISBN 0-941950-13-1

    Good book with sizing info on what adjustments to try when you don't have average proportions.
    Hopefully it's still in print.

    Don't worry about what angles bikes are supposed to have, if it works good it is good.

    "KBH" <[email hidden]> wrote in message news:Ybusa.733301$S_4.757006@rwcrnsc53...

    Quoted message said:

    I thougt 73 was on the steep side already, and that 74 starts to get you into tri bike territory?
    I wouldn't have guessed I was an outlier physically. I would love to see some stats of upper/lower
    leg length for people close to my height - although I don't think my friends would appreciate me
    measuring their legs.

    "Qui si parla Campagnolo" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    kbh-<< Put my bike on the trainer to do a self fitting, using my plumb


    bob

    Quoted message said:

    I

    Quoted message said:

    verified that I was about 1.5" - 2" behind KOPS. My bike has a 73


    degree

    Quoted message said:
    Quoted message said:

    seat tube angle, and I'm using a seatpost with no setback and the saddle rails in the middle.

    Yes, I would say you would benefit from a frameset with a steeper


    seattube

    Quoted message said:
    Quoted message said:

    angle.

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 vecchios.comvecchios.com "Ruote convenzionali costruite eccezionalmente bene"

  18. "KBH" <[email hidden]> wrote in message news:<Ybusa.733301$S_4.757006@rwcrnsc53>...

    Quoted message said:

    I thougt 73 was on the steep side already, and that 74 starts to get you into tri bike territory?
    I wouldn't have guessed I was an outlier physically. I would love to see some stats of upper/lower
    leg length for people close to my height - although I don't think my friends would appreciate me
    measuring their legs.

    74 steep? Depends on your body. My new custom bike will be 78 degrees, and this on a relaxed frame.
    If I were racing the builder would go even steeper. I have short legs, and a relatively short
    femur, so ....

    - rick warner

  19. <snip>

    Quoted message said:
    Quoted message said:

    I thougt 73 was on the steep side already, and that 74 starts to get you into tri bike
    territory? I wouldn't have guessed I was an outlier physically. I would love to see some stats
    of upper/lower leg length


    for

    Quoted message said:
    Quoted message said:

    people close to my height - although I don't think my friends would appreciate me measuring
    their legs.


    <snip> for brevity

    For my height/leg length (5'8" & 30" inseam), I find that the slackest frame I can ride is about 73
    degrees. 73.5-74 and a no offset seatpost work better for me.

    Mike

  20. "KBH" : I thought about that but the ONLY dimensions of the bike, excluding the

    Quoted message said:
    Quoted message said:
    Quoted message said:

    seatpost/saddle, that determine KOPS are seat tube angle, saddle height,


    and

    Quoted message said:
    Quoted message said:

    crank length - that's it. So its gotta be the upper to lower leg ratio,


    not

    Quoted message said:
    Quoted message said:

    the absolute length of the femur.

    But this man is 6'5" so on standard cranks he will need to sit way back to


    get KOPS.

    Quoted message said:

    That argument would only be true if we all rode the same saddle height. Since he is tall, his
    saddle height will be larger, resulting in more "built-in" setback as a result of the seat tube
    angle. Assuming that the relationship between total pubic bone height and saddle height is roughly
    constant (rule of thumb is 0.883 x PBH), then this brings you back to the conclusion that weather
    you're 5'2" or 6'5", it is the ration of upper leg to lower leg that determines KOPS and therefore
    how much seatpost setback you may need and where the saddle may need to be on the rails.

    This argument doesn't make sense unless you factor in a slacker than normal seat tube. Traditionally
    they are a bit slacker on a larger frame. We would need to know what it is at any rate.

    He might also have short feet.

    Andrew Bradley

Active in the last 60 minutes

Active in this thread

0 users · 0 guests ·0 bots ·0 total

No signed-in users are active right now.

No known search crawlers active right now.