Relaxed Seat Tube Angles and KOPS

[Fgwgfitw]

I was reading Keith Bontrager's article about KOPS being a myth
(http://www.bontrager.com/keith/rants.asp?id=12 ) and started thinking about bikes like the Lemonds
with a relax seat tube angle.

If you get a Lemond and adjust the seat so your knee is directly over the pedal axel at 3 o'clock,
wouldn't you be negating the relaxed seat tube angle? The top of the seat tube my be further back,
but if you move the seat forward so your knees are where KOPS wants them to be, aren't you back to
the same position as you would be with a steeper angled tube? Your seat is just mounted on the back
of its rails.

If that's true, then the whole "Lemond Geometry" advantages are dependent upon KOPS being bogus.

Is my thinking correct?

 

[Mike Jacoubowsk]

> If you get a Lemond and adjust the seat so your knee is directly over the pedal axel at 3 o'clock,
> wouldn't you be negating the relaxed seat tube angle? The top of the seat tube my be further back,
> but if you move the
seat
> forward so your knees are where KOPS wants them to be, aren't you back to the same position as you
> would be with a steeper angled tube? Your seat
is
> just mounted on the back of its rails.
>
> If that's true, then the whole "Lemond Geometry" advantages are dependent upon KOPS being bogus.
>

It's not bogus, but your observation is essentially correct. Many bikes achieve "long" top tubes
via a slack seat angle, and other achieve "short" top tubes with a steep seat angle. In my
perfect world, top tube length is measured forward from the point at which a line drops through
the bottom bracket.

Still, armed with both top tube length and seat angle, you can tell if you're going to be able to
make a given geometry work (with a relatively-normal seatpost)... especially useful if you prefer a
more rearword position over the cranks (as LeMond does).

--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

"FGWGFITW" <[email protected]> wrote in message news:[email protected]...
> I was reading Keith Bontrager's article about KOPS being a myth
> (http://www.bontrager.com/keith/rants.asp?id=12 ) and started thinking
about
> bikes like the Lemonds with a relax seat tube angle.
>
> If you get a Lemond and adjust the seat so your knee is directly over the pedal axel at 3 o'clock,
> wouldn't you be negating the relaxed seat tube angle? The top of the seat tube my be further back,
> but if you move the
seat
> forward so your knees are where KOPS wants them to be, aren't you back to the same position as you
> would be with a steeper angled tube? Your seat
is
> just mounted on the back of its rails.
>
> If that's true, then the whole "Lemond Geometry" advantages are dependent upon KOPS being bogus.
>
> Is my thinking correct?
>
>
>

 

[Mark Hickey]

"FGWGFITW" <[email protected]> wrote:

>I was reading Keith Bontrager's article about KOPS being a myth
>(http://www.bontrager.com/keith/rants.asp?id=12 ) and started thinking about bikes like the Lemonds
>with a relax seat tube angle.
>
>If you get a Lemond and adjust the seat so your knee is directly over the pedal axel at 3 o'clock,
>wouldn't you be negating the relaxed seat tube angle? The top of the seat tube my be further back,
>but if you move the seat forward so your knees are where KOPS wants them to be, aren't you back to
>the same position as you would be with a steeper angled tube? Your seat is just mounted on the back
>of its rails.
>
>If that's true, then the whole "Lemond Geometry" advantages are dependent upon KOPS being bogus.
>
>Is my thinking correct?

Yep, you're pretty much dead on. Figure about 1cm of seat clamp change per degree of seat tube angle
(varies by size, of course), and you won't be too far off. So, if two bikes have:

Bike 1 Bike 2 Top tube: 56cm 57cm ST angle: 73.5deg 72.5deg

... the fit will be pretty much identical with the saddle in the same relative position to the
bottom bracket.

The one difference is that the RANGE of saddle position will be further back on the LeMond... which
may be a good or bad thing, depending on how you ride (and which seatpost you choose). A LeMond with
a no-setback post like the Thomson will have a saddle range further forward than other bikes with
more "average" geometry with a Shimano or Campy seatpost.

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

 

[Harris]

"FGWGFITW" wrote:
> I was reading Keith Bontrager's article about KOPS being a myth
> (http://www.bontrager.com/keith/rants.asp?id=12 ) and started thinking
about
> bikes like the Lemonds with a relax seat tube angle.
>
> If you get a Lemond and adjust the seat so your knee is directly over the pedal axel at 3 o'clock,
> wouldn't you be negating the relaxed seat tube angle? The top of the seat tube my be further back,
> but if you move the
seat
> forward so your knees are where KOPS wants them to be, aren't you back to the same position as you
> would be with a steeper angled tube? Your seat
is
> just mounted on the back of its rails.
>
> If that's true, then the whole "Lemond Geometry" advantages are dependent upon KOPS being bogus.

Not necessarily. A slack seat tube is good for someone whose femur (thigh bone) is long in relation
to their overall height. That allows them to get their knee over the pedal spindle while having the
saddle rails centered in the seatpost.

As for KOPS itself, I've read the "myth" article, and find it rather vague. I think KOPS is a good
starting point for anyone. Individual riders may chose a position slightly forward or aft of KOPS
based on personal preference. But you've got to start somewhere. And if you've got the rails
centered using KOPS, then you have the option of moving either forward or back from there.

I don't accept the idea that slack (or steep) seat tubes are right for everyone. It depends on your
proportions. That's what bike fit is all about.

Art Harris

 

[Rk]

"FGWGFITW" <[email protected]> wrote in message news:<[email protected]>...
> I was reading Keith Bontrager's article about KOPS being a myth
> (http://www.bontrager.com/keith/rants.asp?id=12 ) and started thinking about bikes like the
> Lemonds with a relax seat tube angle.
>
> If you get a Lemond and adjust the seat so your knee is directly over the pedal axel at 3 o'clock,
> wouldn't you be negating the relaxed seat tube angle? The top of the seat tube my be further back,
> but if you move the seat forward so your knees are where KOPS wants them to be, aren't you back to
> the same position as you would be with a steeper angled tube? Your seat is just mounted on the
> back of its rails.
>
> If that's true, then the whole "Lemond Geometry" advantages are dependent upon KOPS being bogus.
>
> Is my thinking correct?

No. The advantage of the the Lemond geometry only applies to those of us with relatively
long femurs.

Even using a seatpost with extreme setback, the Lemond is one of the few stock bikes in my size
where I can put the saddle far enough back to even get a KOPS position.

If you have short femurs, then you probably don't want a Lemond.

 

[Doug]

> Not necessarily. A slack seat tube is good for someone whose femur

> (thigh

> bone) is long in relation to their overall height. That allows them to get

> their knee over the pedal spindle while having the saddle rails centered
in

> the seatpost.

Isn't this precisely the "myth" or better yet, the conventional wisdom, that Bontrager Disputes? I
don't agree or disagree with you, but in scanning the article, it seemed he was saying that the
tibil tuberosity need not necessarily be over the spindle.

>

> As for KOPS itself, I've read the "myth" article, and find it rather

> vague.

I agree. It doesn't really offer any alternative. I assume that is because Bontrager prefers his
proprietary formula which he understandibly seeks to maintain as proprietary,

I think KOPS is a good starting point for anyone. Individual

> riders may chose a position slightly forward or aft of KOPS based on

> personal preference. But you've got to start somewhere. And if you've

> got the rails centered using KOPS, then you have the option of moving

> either forward or back from there.

Maybe I'm mistaken, but doesn't Bontrager agree with this (at least when he isn't fitting
the frame)?

> I don't accept the idea that slack (or steep) seat tubes are right for

> everyone. It depends on your proportions.

And personal preferences?

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

 

[Tim McNamara]

"Doug" <dougjg@REMOVE_THISearthlink.net> writes:

> > Not necessarily. A slack seat tube is good for someone whose femur (thigh bone) is long in
> > relation to their overall height. That allows them to get their knee over the pedal spindle
> > while having the saddle rails centered in the seatpost.
>
> Isn't this precisely the "myth" or better yet, the conventional wisdom, that Bontrager Disputes? I
> don't agree or disagree with you, but in scanning the article, it seemed he was saying that the
> tibil tuberosity need not necessarily be over the spindle.

Bontrager's assertion seems to be that KOPS is a myth and that it's better to find the balance point
of the rider's center of gravity. KOPS is certainly not the be-all and end-all of bicycle fitting-
there are many factors.

> > As for KOPS itself, I've read the "myth" article, and find it rather vague.
>
> I agree. It doesn't really offer any alternative. I assume that is because Bontrager prefers his
> proprietary formula which he understandibly seeks to maintain as proprietary,

As is the case with most "fitting" methods.

> I think KOPS is a good starting point for anyone. Individual > riders may chose a position
> slightly forward or aft of KOPS based on
> > personal preference. But you've got to start somewhere. And if
> you've > got the rails centered using KOPS, then you have the option of moving > either forward or
> back from there.
>
> Maybe I'm mistaken, but doesn't Bontrager agree with this (at least when he isn't fitting
> the frame)?

That's my take on his position (no pun intended). And it's a reasonable idea that I think few
framebuilders would argue with. With the clamp at the center of the rails, one can get the
equivalent of 1 to 1.5 degrees either way on the effective seat tube angle.

> > I don't accept the idea that slack (or steep) seat tubes are right for everyone. It depends on
> > your proportions.
>
> And personal preferences?

Why not? Some people prefer a very forward position- sometimes this is related to applications
(track racers, triathletes) and sometimes just a matter of preference. Your muscles adapt to
the position.

 

[Dirtroadie]

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

> If that's true, then the whole "Lemond Geometry" advantages are dependent upon KOPS being bogus.

Lemond geometry advantages? Holy ****! I find this whole subject fascinating more as a matter of of
marketing psychology than of anything technical relating to the bicycle. I happen to ride a "Lemond"
OCLV frame (I liked the color). On several occasions recently I have had people (all of whom
happened to be riding Lemond steel bikes) comment along the lines of "Oh, is that carbon?" To which
I would respond "Yes, Trek bought Lemond and it's a Trek OCLV with Lemond decals" (which to the best
of my knowledge is true). Normally I would expect that to be the end of the discussion, but
invariably it continues with them stating like "You know, for that to be a Lemond, Greg had to have
input into the geometry." Morons, they're bleeping morons.

It is at that point that I have very little to say. The damn frame (MY damn frame) came out of the
same molds as every other Trek OCLV. These "Lemond" people are so swept up in the BS of the
purported "advantages" of "Lemond geometry" that there's nothing to discuss. "Lemond geometry" is a
great thing - for Greg Lemond and those proportioned like him. But to think that there is something
magical about this geometry is to believe in the tooth fairy. Hey, Greg was a great rider, but just
because he wears a particular size of shoe doesn't mean that I should wear the same.

Bike frame geometry is not so complicated that one company can have a distinct advantage in
performance by merely changing seat tube angle. If seat tube angle by itself were a significant
performance advantage it would have long ago been figured out that everybody else was wrong. But
that simply hasn't happened and won't happen because it isn't so.

Does anybody recall the "chopper" bike a ridden by Steve Bauer in the early '90s? A perfect example
of erroneous "if a little is good, then a lot is better" thinking.

Having a bike that fits is a good thing. Having a bike that is a good fit for somebody else does not
fall into the same category even if you can tell everybody else that does. Which is what the whole
"Lemond advantage" is about.

Lemond bikes? I like 'em. LeMond geometry? If you believe in that I have a bridge in New York that
you might be interested in buying.

DR