My thoughts on seat position, crank length, and cleat position

The Burke formula for 175's seems to reccommend a much higher seating
position than the Lemond formula you were using for the 175's so the devil
in me still wonders if you could have reined in your ankle and knee motion
by raising the seat way over the Lemond mark despite the fact that it would
go against conventional wisdom. My main grudge with formulas is that they
sometimes form a psychological barrier against testing these things out, but
if what you chose works good, it is good. I guess my idea of a good formula
is one that helps a rider ride well with the equipment they've got as well
as the the equipment they ought to have (to paraphrase Rumsfeld) .

wrote in message
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Lee Hurd wrote:
Me if you look back at the figures I posted earlier. Interesting.

Did the longer cranks solve the catch in your pedal stroke by the way?

Yes, the stumbling, catching sensation is gone. I think that feeling
had something to do with the range of knee flexion (or whatever it is
called) as related to degrees of crank rotation during the power
stroke.

Seems several folks fall comfortably into the 109%, 20.8%, kops range.

Joseph

Lee Hurd wrote:
The Burke formula for 175's seems to reccommend a much higher seating
position than the Lemond formula you were using for the 175's so the devil
in me still wonders if you could have reined in your ankle and knee motion
by raising the seat way over the Lemond mark despite the fact that it would
go against conventional wisdom. My main grudge with formulas is that they
sometimes form a psychological barrier against testing these things out, but
if what you chose works good, it is good. I guess my idea of a good formula
is one that helps a rider ride well with the equipment they've got as well
as the the equipment they ought to have (to paraphrase Rumsfeld) .


I tried lots of things with the 175's. From super low to very high
(felt that way at least), like recommended from the fit calculator at
competitivecyclist.com. I tried so high I couln't reach the pedals, and
eveything in between.

I agree about the psychological limitations of folmulas. That is why I
eventually gave up and just moved the seat around blindly. Out on rides
I even had a riding buddy make changes while I wasn't looking to try to
avoid bias. Sometimes he only told me he moved it! That is why I was
all th emore surprised when I "discovered" the 109% fit. I actually
didn't know about the 109% formula until once I had found a saddle
height I liked, I tried googling around to see if it had any basis of
any kind, when I found:

http://www.asep.org/jeponline/issue/...elerSaddle.pdf

I think my problem was I didn't have enough knee motion, so higher
wouldn't have helped there.

Speaking "riding the ride with the bike you've got" my buddy who helped
with the seat height rides a super-heavy department-store hybrid that
is way to big for him, that he borrowed from somebody. He punishes me.

Joseph





wrote in message
ups.com...

Lee Hurd wrote:
Me if you look back at the figures I posted earlier. Interesting.

Did the longer cranks solve the catch in your pedal stroke by the way?

Yes, the stumbling, catching sensation is gone. I think that feeling
had something to do with the range of knee flexion (or whatever it is
called) as related to degrees of crank rotation during the power
stroke.

Seems several folks fall comfortably into the 109%, 20.8%, kops range.

Joseph

Rebecca Morris wrote:
For another data point, I also tried using a longer crank. I have an inseam
of about 96 cm, so I tried a 190 mm crank. This is a bit shorter than the
formula, but I was afraid that a longer crank would have too little ground
clearance on turns. I started out with a 175mm crank.

The longer crank felt good for a while - especially on climbs - but I
eventually (a few months later) had a lot of calf pain in both legs. I
tried different seat heights and cleat positions, but nothing solved the
problem. I went back to the 175mm cranks and the pain subsided.

I then decide to try the 190mm cranks again and very quickly had the calf
pain back. I then gave up. Leg pain was one of the warning I heard about
long cranks. They were right.... for me....

I may have been slightly faster on climbs with the longer crank, but my
average speed never changed much - maybe 3-4 minutes out of a 4 hour hilly
ride.

In the year since the change back to the 175mm crank I have been changing my
cleat position and seat height in an effort to optimize my position. I now
have the cleat on the ball of my foot and the seat is at about 108%. I plan
to try 109% when I get a new seat - the old one has started to bother me.

Based on what I have heard from the coaches comments (web page searches) the
bicycle manufacturers' offering, and my own experience, I suspect the
scaling may be more like the square root of leg length rather than linear
with leg length. Moment of inertia scaling?

Anyway, that is my story. Good luck with your experiments.


What height were you using with the 190's? Perhaps an intermediate size
like 180-185 would do the trick, if you aren't satisfied with the
175's. Do you still have the 190's? I have some 180's, maybe we can
swap?

One of the reasons I like having a forward cleat position is to make
sure my calf muscles get in on the action. I have somewhat muscular
(and thus heavy) calves that would be a waste to just be moving around
even in small circles. (I can only use certain bottle cages on the seat
tube or else they rub). The efficiency of moving them in larger circles
with longer cranks remains to be seen, but looks good so far.

Where was your calf pain, and what sort? Are you a spinner? What sort
of build do you have?

Joseph

On 9 Nov 2005 05:45:53 -0800, wrote:

No wind, and I use a hill steep enough that for my speed (about 15
km/h, or 9.3 mph) there is no significant wind resistance. If I
estimate the weight of soaking wet clothes and rims full of water to be
about 2 kg, the calculation gives me 311 watts, vs 289.5 watts I
recorded earlier in the season with dry clothes, and shorter cranks

And if you assume the extra water weighs 100 grams?


Jasper

My entire calves hurt on both legs no matter what I did. I'm about 6'4" and
185 lbs, so I'm a bit lighter than most my height. I usually turn the
cranks at about 70-75 up hill and about 88-92+ on the flats.

Definitely not a muscular type.

I tried moving the cleats back when using the 190's, but more than a little
back hurts the smoothness of my pedal stroke. With the 175's I like the
cleats at the ball of the foot.

I still have the 190's - they are a triple from High Sierra along with a BB.
Are the 180's a triple? The bike is all set up for a triple and I don't
want to change.


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oups.com...

Rebecca Morris wrote:
For another data point, I also tried using a longer crank. I have an
inseam
of about 96 cm, so I tried a 190 mm crank. This is a bit shorter than
the
formula, but I was afraid that a longer crank would have too little
ground
clearance on turns. I started out with a 175mm crank.

The longer crank felt good for a while - especially on climbs - but I
eventually (a few months later) had a lot of calf pain in both legs. I
tried different seat heights and cleat positions, but nothing solved the
problem. I went back to the 175mm cranks and the pain subsided.

I then decide to try the 190mm cranks again and very quickly had the calf
pain back. I then gave up. Leg pain was one of the warning I heard about
long cranks. They were right.... for me....

I may have been slightly faster on climbs with the longer crank, but my
average speed never changed much - maybe 3-4 minutes out of a 4 hour
hilly
ride.

In the year since the change back to the 175mm crank I have been changing
my
cleat position and seat height in an effort to optimize my position. I
now
have the cleat on the ball of my foot and the seat is at about 108%. I
plan
to try 109% when I get a new seat - the old one has started to bother me.

Based on what I have heard from the coaches comments (web page searches)
the
bicycle manufacturers' offering, and my own experience, I suspect the
scaling may be more like the square root of leg length rather than linear
with leg length. Moment of inertia scaling?

Anyway, that is my story. Good luck with your experiments.


What height were you using with the 190's? Perhaps an intermediate size
like 180-185 would do the trick, if you aren't satisfied with the
175's. Do you still have the 190's? I have some 180's, maybe we can
swap?

One of the reasons I like having a forward cleat position is to make
sure my calf muscles get in on the action. I have somewhat muscular
(and thus heavy) calves that would be a waste to just be moving around
even in small circles. (I can only use certain bottle cages on the seat
tube or else they rub). The efficiency of moving them in larger circles
with longer cranks remains to be seen, but looks good so far.

Where was your calf pain, and what sort? Are you a spinner? What sort
of build do you have?

Joseph

Actually yesterday I weighed myself after a ride in the rain with the
same clothes. Shoes, helmet, tights, jacket, gloves, shorts, socks,
booties, and shirt soaking wet weighed 4 kg. I haven't weighed a dry
set of summer gear, but it certainly is less than 3.9kg!

j

Rebecca Morris wrote:
My entire calves hurt on both legs no matter what I did. I'm about 6'4" and
185 lbs, so I'm a bit lighter than most my height. I usually turn the
cranks at about 70-75 up hill and about 88-92+ on the flats.

Definitely not a muscular type.

I tried moving the cleats back when using the 190's, but more than a little
back hurts the smoothness of my pedal stroke. With the 175's I like the
cleats at the ball of the foot.

Does it feel right? Or do you still feel like giving longer cranks a
try?

I still have the 190's - they are a triple from High Sierra along with a BB.
Are the 180's a triple? The bike is all set up for a triple and I don't
want to change.

My 180's are Campy double. But if you don't plan on using the 190's
anymore, I might be interested in buying them for my mountain bike.

Joseph

Ron Ruff wrote:
The ranges are usually quite large... I think 120-220mm in one test
that I recall.

Yup, that would be my study. Minor differences in maximal power from
120-220mm (see Euro JAP 2001 and for the hard science verson see J
Biomechanics 2000). In a follow up study (JAP 2002, First author John
McDaniel), no difference in efficiency on cranks ranging from 145 to
195mm. Do a Google scholar search for "Martin, JC" AND crank and you
should find them.

The bad news is that no crank will give you a magical improvement.

The good news is that you are free to ride the crank length you LIKE the
best. The one that makes you FEEL the best. Chances are the better you
like the way your bike feels the better you will ride. Call it placebo
effect, but if placebo effect wasn't imporant, we wouldn't need to
control for it in studies would we?

Ride what makes you happy,

Jim

Jim Martin wrote:
Ron Ruff wrote:
The ranges are usually quite large... I think 120-220mm in one test
that I recall.

Yup, that would be my study. Minor differences in maximal power from
120-220mm (see Euro JAP 2001 and for the hard science verson see J
Biomechanics 2000). In a follow up study (JAP 2002, First author John
McDaniel), no difference in efficiency on cranks ranging from 145 to
195mm. Do a Google scholar search for "Martin, JC" AND crank and you
should find them.

The bad news is that no crank will give you a magical improvement.

The good news is that you are free to ride the crank length you LIKE the
best. The one that makes you FEEL the best. Chances are the better you
like the way your bike feels the better you will ride. Call it placebo
effect, but if placebo effect wasn't imporant, we wouldn't need to
control for it in studies would we?

Ride what makes you happy,

Jim

I just read your "Determinants of Metabolic Cost During Submaximal
Cycling" and an abstract of "Determinants of maximal cycling power:
crank length, pedaling rate and pedal speed." (I couldn't find the full
text freely available)

Those are quite interesting. It always made sense to me that the
cardio-vascular system was the weak link in maximal power, and thus
relative ineficiencies related to crank length would have no real
effect. But what about duration of sustainable maximum power? This is
probably in the full text article, but was that affected by
crank-length? How was seat height determined for the various crank
lengths?

In the submaximal article the weights of the 9 riders is mentioned, but
nothing about their heights. Is it possible that these findings do not
scale upward? In other words, might rider size or build magnify some of
the effects? I don't understand fully how the distinction between pedal
speed and force applied to the pedal is made. It seems to me this is
what the crank arm length issue boils down to: the tradeoff between
pedal speed and pedal force, with your research suggesting that the two
essentially cancel each other, but perhaps this trade-off (if indeed it
is a trade-off) is very dependant on rider build.

What do you think would happen were you to do these experiments with
more fine-grained crankarm lengths? It seems to me the jump from 170mm
to 195mm may mask a lot of interesting info, particularly when the test
subjects are all of somewhat normal size. It might also be interesting
to see what happens with riders of similar height, but drastically
different builds. Was this 170-195 jump due to logistic/budget issues,
or was there some other reason?

Placebo, or mechanical benefit, I'll take the extra watts and reduced
metabolic costs!

Any chance of you doing more research of this type any time soon?

Joseph

wrote:
But what about duration of sustainable maximum power?

I'm not sure what you mean by this. something like time trial power? If
so, that gets to be a difficult thing to measure. So far we have stayed
away from performance trials.

This is
probably in the full text article, but was that affected by
crank-length? How was seat height determined for the various crank
lengths?

We set the seat ht from seat to pedal, at its most extended position,
the same for all crank lengths.

In the submaximal article the weights of the 9 riders is mentioned, but
nothing about their heights. Is it possible that these findings do not
scale upward?

I suppose that's possible but I really doubt it. Also, for the max power
studies, I specifically recruited the tallest and shortest cyclists I
could find. The means may not be impressive but the range was pretty large.

What do you think would happen were you to do these experiments with
more fine-grained crankarm lengths?

If there's no difference in an inch there will not likely be any
difference in 2.5mm


Placebo, or mechanical benefit, I'll take the extra watts and reduced
metabolic costs!

Any chance of you doing more research of this type any time soon?

Possibly. We have some indication that the ability to excite and relax
the muscle (pedaling rate) may be more subject to fatigue than muscle
force-velocity characteristits (pedal speed) and we'd like to take a
look at that. Keep in mind that my students and I do not study cycling.
We use cycing as a model to get at more basic questions of neuromuscular
function.

Cheers,

Jim