An inch behind KOPS: Anybody doing it?

Discussion in 'Cycling Equipment' started by x, Jan 22, 2003.

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  1. x

    x Guest

    Just picked up a new custom hardtail frame and it looks like something went way wrong with the frame
    tube/angle calculation.

    The best I can get with the saddle all the way forward is my knee a good inch in back of the
    pedal spindle.

    I've ridden in front of KOPS - on a too-short frame. Main effect seemed to be to put my butt too far
    back on the saddle as my bod found KOPS on it's own while riding.

    But this is the first time I've had a too-long frame and been behind KOPS - seems like the narrowing
    of the saddle as one moves forward would mitigate against my bod finding KOPS on it's own.

    The reason I'm trolling for someobody who rides behind KOPS is that I'd like to think this isn't
    a total loss and I'm going to be able to ride it without the prospect of repetitive-use injury
    to my knees.

    But I wouldn't want to find out the hard way....

    Comments?
    -----------------------
    Pete Cresswell
     
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  2. Tim McNamara

    Tim McNamara Guest

    In article <[email protected]>, "(Pete Cresswell)" <[email protected]> wrote:

    > Just picked up a new custom hardtail frame and it looks like something went way wrong with the
    > frame tube/angle calculation.

    Shouldn't that be the builder's problem to rectify?

    > The best I can get with the saddle all the way forward is my knee a good inch in back of the pedal
    > spindle.
    >
    > I've ridden in front of KOPS - on a too-short frame. Main effect seemed to be to put my butt too
    > far back on the saddle as my bod found KOPS on it's own while riding.
    >
    > But this is the first time I've had a too-long frame and been behind KOPS - seems like the
    > narrowing of the saddle as one moves forward would mitigate against my bod finding KOPS on
    > it's own.
    >
    > The reason I'm trolling for someobody who rides behind KOPS is that I'd like to think this isn't
    > a total loss and I'm going to be able to ride it without the prospect of repetitive-use injury to
    > my knees.

    Most Euro pro road racers ride with their knees well behind KOPS, from the looks of them in photos.
    20,000 miles a year or more that way. Probably not a big deal, unless it makes your position
    uncomfortable or adversely affects handling.

    Personally, if the error was the frame builder's I wouldn't accept the frame. I'd return it. Would
    you accept a suit from a tailor that didn't fit?
     
  3. Mark Hickey

    Mark Hickey Guest

    "(Pete Cresswell)" <[email protected]> wrote:

    >Just picked up a new custom hardtail frame and it looks like something went way wrong with the
    >frame tube/angle calculation.
    >
    >The best I can get with the saddle all the way forward is my knee a good inch in back of the
    >pedal spindle.
    >
    >I've ridden in front of KOPS - on a too-short frame. Main effect seemed to be to put my butt too
    >far back on the saddle as my bod found KOPS on it's own while riding.
    >
    >But this is the first time I've had a too-long frame and been behind KOPS - seems like the
    >narrowing of the saddle as one moves forward would mitigate against my bod finding KOPS on
    >it's own.
    >
    >The reason I'm trolling for someobody who rides behind KOPS is that I'd like to think this isn't
    >a total loss and I'm going to be able to ride it without the prospect of repetitive-use injury to
    >my knees.
    >
    >But I wouldn't want to find out the hard way....

    FWIW, I tend to ride further back (relative to KOPS) on my MTB - I do more climbing and it helps me
    get my glutes into the game. It does tend to make my front end a bit lighter though, and I have to
    be careful not to wash out the front tire in sandy areas (and there are a LOT of those in Arizona).

    BTW, are you measuring the KOPS while in your normal riding position? If not, you may find that the
    shock will compress enough to move your knee considerably further forward (though I doubt an inch).

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

    Jeff Wills Guest

    "(Pete Cresswell)" <[email protected]> wrote in message
    news:<[email protected]>... <snip>
    > The reason I'm trolling for someobody who rides behind KOPS is that I'd like to think this isn't
    > a total loss and I'm going to be able to ride it without the prospect of repetitive-use injury to
    > my knees.
    >
    > But I wouldn't want to find out the hard way....
    >
    > Comments?

    I've ridden for 12 years and tens of thousands of miles with my knees well behind KOPS. My knees are
    quite happy.

    The rest of me is pretty happy, too- I ride recumbents. :)

    I'd say that you should adjust the seat in the middle of the rails; put on a tall, short reach stem;
    and ride the heck out of the bike.

    Jeff

    Jeff
     
  5. Mike S.

    Mike S. Guest

    I'm only about 1cm behind KOPS and don't have any problems.

    Did you do the measurement yourself? If so, have someone else try while you just sit on the bike.
    I've noticed that when I'm fitting friends, that if they're looking at what I'm doing, it affects
    the measurements.

    Mike

    "(Pete Cresswell)" <[email protected]> wrote in message news:[email protected]...
    > Just picked up a new custom hardtail frame and it looks like something
    went way
    > wrong with the frame tube/angle calculation.
    >
    > The best I can get with the saddle all the way forward is my knee a good
    inch in
    > back of the pedal spindle.
    >
    > I've ridden in front of KOPS - on a too-short frame. Main effect seemed
    to be
    > to put my butt too far back on the saddle as my bod found KOPS on it's own
    while
    > riding.
    >
    > But this is the first time I've had a too-long frame and been behind
    KOPS -
    > seems like the narrowing of the saddle as one moves forward would mitigate against my bod finding
    > KOPS on it's own.
    >
    > The reason I'm trolling for someobody who rides behind KOPS is that I'd
    like to
    > think this isn't a total loss and I'm going to be able to ride it without
    the
    > prospect of repetitive-use injury to my knees.
    >
    > But I wouldn't want to find out the hard way....
    >
    > Comments?
    > -----------------------
    > Pete Cresswell
     
  6. x

    x Guest

    RE/
    >BTW, are you measuring the KOPS while in your normal riding position? If not, you may find that the
    >shock will compress enough to move your knee considerably further forward (though I doubt an inch).

    I'm not sure. I'm measuring it the same way as on my 'real' bike, though: I get on the bike, put my
    butt where the indents are on the saddle, set a crank parallel to the ground, and drop the plumb bob
    with the line against my kneecap.

    Right or wrong, the other bike seems to work - no knee problems and, to me at least, a comfortable
    riding position - albiet a very light front end from the setback seatpost.

    My knees definately tell me about it when I do 20-30 miles on my utility bike - on which the knees
    are forward of KOPS.

    OTOH, I just heard from somebody else that being behind KOPS doesn't seem to cause injury - in fact
    this person seemed to think that a lot of professional road riders ride that way anyhow.

    That being the case, I think I'll try to work with this thing for awhile and see if I can live with
    it. KOPS isn't a matter of principle - I'm just looking for something that works.

    Also, this bike is intended just as a "go anywhere" road bike and a travel bike (I got it with the
    B&S couplings). If things don't work out, I may be throwing myself on you guy's mercy....which is
    probably what I should have done in the first place...depending on a cost comparison between
    re-making this one "right" and going titanium. The second time around on this end should have a 100%
    chance of success given that we have a concrete reference point - so that part of the decision is
    probably a wash.
    -----------------------
    Pete Cresswell
     
  7. x

    x Guest

    With 5 3/4 inches of seatpost extension to play with, I'm thinking a viable workaround (instead of
    junking the frame) would be brazing together a faux seatpost/seat tube: something that sticks down
    into the seat tube on the bottom side and presents an offset section of seat tube to stick the real
    seatpost into on the top side. The real seatpost could be trimmed so it doesn't hit the top tube.

    Dunno how much overlap is necessary when sticking one tube into another, but I'd guess the amount
    isn't that much, is well known, relates to the diameter of the tubes in question, and is a lot less
    than 5 3/4 inches.

    Not real elegant, but seems like it would get the saddle up where my butt is without dropping a
    bundle on another frame...
    -----------------------
    Pete Cresswell
     
  8. I don't see mention of whether your seatpost has any setback. If it does, as most do, you might find
    your answer there. There's quite a range of seatposts on the market, some with no setback and some
    made for negative setback (intended for triathletes, mainly). Control Tech used to make reversible
    ones which were quite common; you might find one of those lying about or maybe on ebay. From a
    typical setback post to an inline post will get you close to an inch right there, and the tri or
    reversible posts even more. Saddles also vary a fair amount in how much fore-aft range of adjustment
    the rails allow. I'd go for either of the above before a mudge like you're talking about.

    SB

    "(Pete Cresswell)" <[email protected]> wrote in message news:[email protected]...
    > With 5 3/4 inches of seatpost extension to play with, I'm thinking a
    viable
    > workaround (instead of junking the frame) would be brazing together a faux seatpost/seat tube:
    > something that sticks down into the seat tube on the
    bottom
    > side and presents an offset section of seat tube to stick the real
    seatpost into
    > on the top side. The real seatpost could be trimmed so it doesn't hit
    the top
    > tube.
    >
    > Dunno how much overlap is necessary when sticking one tube into another,
    but I'd
    > guess the amount isn't that much, is well known, relates to the diameter
    of the
    > tubes in question, and is a lot less than 5 3/4 inches.
    >
    > Not real elegant, but seems like it would get the saddle up where my butt
    is
    > without dropping a bundle on another frame...
    > -----------------------
    > Pete Cresswell
     
  9. On Mon, 20 Jan 2003 13:56:00 -0700, (Pete Cresswell) wrote:
    > OTOH, I just heard from somebody else that being behind KOPS doesn't seem to cause injury - in
    > fact this person seemed to think that a lot of professional road riders ride that way anyhow.

    It can cause injury, but not where you may think. If you are not pushing "down" when you pedal your
    butt will move forward and back on the seat making saddle sores much more likely on long rides.
    Unfortuately, you may not know that you have a problem until part way through a long ride. Do
    sequential long days in the saddle before a week long (or longer) ride.

    Richard Kaiser
     
  10. x

    x Guest

    RE/
    >It can cause injury, but not where you may think. If you are not pushing "down" when you pedal your
    >butt will move forward and back on the seat

    I'm already noticing that - lots of sliding back-and-forth. I'm also thinking that an unexpected big
    bump in the "forth" position could ruin my whole day....
    -----------------------
    Pete Cresswell
     
  11. Tim McNamara

    Tim McNamara Guest

    In article <[email protected]>, "(Pete Cresswell)" <[email protected]> wrote:

    > RE/
    > >It can cause injury, but not where you may think. If you are not pushing "down" when you pedal
    > >your butt will move forward and back on the seat
    >
    > I'm already noticing that - lots of sliding back-and-forth. I'm also thinking that an unexpected
    > big bump in the "forth" position could ruin my whole day....

    Have you lowered the saddle to compensate for it being farther back?
     
  12. x

    x Guest

    RE/
    >Have you lowered the saddle to compensate for it being farther back?

    Never thought about that.

    Sounds like when I do the knee straight, heel on pedal thing, the pedal needs to be cocked a little
    forwards of straight down.
    -----------------------
    Pete Cresswell
     
  13. Donald Munro

    Donald Munro Guest

    Pete Cresswell wrote:

    > With 5 3/4 inches of seatpost extension to play with, I'm thinking a viable workaround (instead
    > of junking the frame) would be brazing together a faux seatpost/seat tube: something that sticks
    > down into the seat tube on the bottom side and presents an offset section of seat tube to stick
    > the real seatpost into on the top side. The real seatpost could be trimmed so it doesn't hit the
    > top tube.
    >
    > Dunno how much overlap is necessary when sticking one tube into another, but I'd guess the amount
    > isn't that much, is well known, relates to the diameter of the tubes in question, and is a lot
    > less than 5 3/4 inches.
    >
    > Not real elegant, but seems like it would get the saddle up where my butt is without dropping a
    > bundle on another frame...

    The Profile Fast Forward seatpost might also be an alternative or perhaps the Look ErgoPost.
     
  14. x

    x Guest

    RE/
    >From a typical setback post to an inline post will get you close to an inch right there, and
    >the tri or reversible posts even more. Saddles also vary a fair amount in how much fore-aft
    >range of adjustment the rails allow. I'd go for either of the above before a mudge like you're
    >talking about.

    I'm wedded to the Brooks B-17.

    As far as seatposts go, the ThudBuster I want to use on this bike (it's a hardtail) looks to have
    about a half-inch inherant setback in it. But that's non-negotiable: my tender tush just doesn't
    thrive on solid-rail saddles.

    I *could* go to the four-wire Brooks B-72, and have done so in the past - but that's only going to
    pick up that half inch.

    Considering that when I config this thing for my Rohloff hub and tension the chain via the eccentric
    BB we're going to add another half-to-three-quarters inch I think I'm looking at wanting about two
    inches of forward shift (given that may be a little too much, but now the saddle is all the way
    forward on it's rails - so there'll be some room for adjustment there...
    -----------------------
    Pete Cresswell
     
  15. x

    x Guest

    RE/
    >The Profile Fast Forward seatpost might also be an alternative or perhaps the Look ErgoPost.

    That's the idea - but I want a sus post - specifically the ThudBuster.

    -----------------------
    Pete Cresswell
     
  16. Peter Vesel

    Peter Vesel Guest

    Read this

    http://www.sheldonbrown.com/kops.html

    everybody is slightly different. What is good for one person might injure another.

    Personally i ride way behind the bottom bracket. I don't know how far behind my knee is.....and I
    don't care.....i just make sure the saddle is in the right place and that sets everything else up

    Peter
     
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