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

Hi Everyone,

I think I have finally settled into a position I am comfortable with
and I hope will allow for maximal power output and maximum efficiency
at sub-maximal power outputs. In other words, improved endurance.

First a summary of my situation, then a description of my "solution"
and thoughts on why it seems to work.

My inseam (varies by time of day, compression of meniscus?) seems to be
95cm, my feet are size 50 (305mm long). When I was in my 20's I weighed
about 93 kg (205 lbs), was rather fit, and didn't have any problems
with comfort even on long rides. I used 177.5mm cranks on my road bike,
180's on the time-trial bike. I used LeMond's inseam x 0.883 for seat
height with a little downward fudge for crank length. Knee slightly
forward of the spindle. Way stretched out with a long top-tube and the
longest Cinelli stem I could find.

After a 10 year hiatus I bought a new bike and started riding again.
Once I got down to 105kg I started experimenting with positioning to
find an optimal setting. My hands had problems with numbness, but I
attibuted that to overweight upper body, and rough pavement. My new
bike had 175mm cranks. As my weight dropped to 100kg, the numbness
persisted, and I figured I had to do something about it. So I moved my
saddle slowly rearward to get weight off my arms, as well as raised the
bars, and moved them rearward. I tried a very large range, and the
numbness improved but did not go away. But pedaling always felt
sub-optimal. Standing was a waste of time, and on flats in a tuck I
kept slipping forward on the saddle. On seated climbs I would ankle
quite a bit and slide my butt bones all the way off the rear of the
saddle. I had my cleats set very neutral, but thought I'd try moving
them back to compensate for my large feet, in an attempt to make my
pedalling feel more normal. I didn't notice any real change except my
monster ankling on steep climbs wasn't as effective.

I became intrigued by the "proportional cranks" argument and set about
thinking how it could benefit me. It didn't take much to convince me
that proportional makes sense, and were worth a try. The difference has
been amazing. It took a while to get the seat height right, and I ended
up trying all sorts of crazy combos until I found what felt right. When
I measured the height it corresposnds to 109% of inseam from seat to
pedal spindle. Coincidently a magic number touted my Ed Burke and
others. I also found my knee was right over the pedal spindle. Another
coincidence factor. Everything seemed to be so "normal" that I tried
moving my cleats back to right under the ball of my foot. Again
everyting seemed to just click. I have a pet theory that the
conventional wisdom of large feet benefiting from reaward cleat
position is just a kludge to overcome what is actually people using
cranks that are too short. The issue isn't large feet, the issue is the
long legs attached to those feet!Now in a tuck I don't side forward,
and ankling up steep climbs I don't slide back at all. I shove back a
bit, but not any more than can be taken up by the slack in flesh. My
bars are slighlty higher than they were relative to the seat (about
1cm) but are now 2cm further forward. My fore-aft balance on the bike
seems much better and the numbness in the hands is gone. And even
standing on climbs feels good. Instead of feeling as though I was
teetering on top of a flag pole, I feel like I get good solid strides.

But the real fun came when I went to measure my power on a long hill.
At the peak of the season a few months ago on 175mm cranks I measured
my output at almost 290 watts by plugging values into
analyticcycling.com. Yesterday with my 195's I calculated over 300
watts, despite having not ridden so much in the last 6 weeks. And it
was pouring rain so my clothes held some unknown mass of water, which
lets me know the output is even a little higher. (My wife gave me one
of those looks when I said I was going to traipse through the house in
sopping wet gear to weigh myself, so the exact weight is unknown for
now...).

I know there are studies showing that crank-length has almost no
bearing on power output, but I think they maybe did not study a wide
enough range. Or perhaps I just am lucky. I haven't been on any rides
longer than 110km with the new cranks, so I don't know how it will play
out endurance-wise.

I think the key is juggling the variables of power (speed), cadence,
and pedal force. The extra leverage afforded by using cranks that are
not drastically undersized allows a lighter force to be applied to
achive a given power at a comfortable cadence. Cadence and force
obviously play into eachother, and when you can't get them to jive, it
isn't strange that it feels funny, or that power is sub-optimal. This
lighter force at least in my case more than makes up for the greater
pedal distance and pedal speed required for a given cadence.

So my new fit seems pretty normal:

seat height (from bb) = (inseam x 1.09) - crank length
seat fore-aft: knee over spindle
cleats: neutral

But it is all only possible by using cranks of length 20.8% of inseam.

Are there many folks using cranks 20.8% of inseam who also have seat
position set similarly, but are of a scale that results in more normal
length cranks like 172.5?

Joseph

Well, almost. I have a 33" inseam (838mm) and use a 175 crank, which is
~20.8%. My saddle height is 737mm, which is what your formula works out to
as well, but that is to the top of the seat clamp (or to the saddle rails),
NOT to the top of the saddle surface itself. That dimension is a full 50mm
higher. I can't imagine riding that much lower, if that's what you are
suggesting. Hmmm...
wrote in message
oups.com...
Hi Everyone,

I think I have finally settled into a position I am comfortable with
and I hope will allow for maximal power output and maximum efficiency
at sub-maximal power outputs. In other words, improved endurance.

First a summary of my situation, then a description of my "solution"
and thoughts on why it seems to work.

My inseam (varies by time of day, compression of meniscus?) seems to be
95cm, my feet are size 50 (305mm long). When I was in my 20's I weighed
about 93 kg (205 lbs), was rather fit, and didn't have any problems
with comfort even on long rides. I used 177.5mm cranks on my road bike,
180's on the time-trial bike. I used LeMond's inseam x 0.883 for seat
height with a little downward fudge for crank length. Knee slightly
forward of the spindle. Way stretched out with a long top-tube and the
longest Cinelli stem I could find.

After a 10 year hiatus I bought a new bike and started riding again.
Once I got down to 105kg I started experimenting with positioning to
find an optimal setting. My hands had problems with numbness, but I
attibuted that to overweight upper body, and rough pavement. My new
bike had 175mm cranks. As my weight dropped to 100kg, the numbness
persisted, and I figured I had to do something about it. So I moved my
saddle slowly rearward to get weight off my arms, as well as raised the
bars, and moved them rearward. I tried a very large range, and the
numbness improved but did not go away. But pedaling always felt
sub-optimal. Standing was a waste of time, and on flats in a tuck I
kept slipping forward on the saddle. On seated climbs I would ankle
quite a bit and slide my butt bones all the way off the rear of the
saddle. I had my cleats set very neutral, but thought I'd try moving
them back to compensate for my large feet, in an attempt to make my
pedalling feel more normal. I didn't notice any real change except my
monster ankling on steep climbs wasn't as effective.

I became intrigued by the "proportional cranks" argument and set about
thinking how it could benefit me. It didn't take much to convince me
that proportional makes sense, and were worth a try. The difference has
been amazing. It took a while to get the seat height right, and I ended
up trying all sorts of crazy combos until I found what felt right. When
I measured the height it corresposnds to 109% of inseam from seat to
pedal spindle. Coincidently a magic number touted my Ed Burke and
others. I also found my knee was right over the pedal spindle. Another
coincidence factor. Everything seemed to be so "normal" that I tried
moving my cleats back to right under the ball of my foot. Again
everyting seemed to just click. I have a pet theory that the
conventional wisdom of large feet benefiting from reaward cleat
position is just a kludge to overcome what is actually people using
cranks that are too short. The issue isn't large feet, the issue is the
long legs attached to those feet!Now in a tuck I don't side forward,
and ankling up steep climbs I don't slide back at all. I shove back a
bit, but not any more than can be taken up by the slack in flesh. My
bars are slighlty higher than they were relative to the seat (about
1cm) but are now 2cm further forward. My fore-aft balance on the bike
seems much better and the numbness in the hands is gone. And even
standing on climbs feels good. Instead of feeling as though I was
teetering on top of a flag pole, I feel like I get good solid strides.

But the real fun came when I went to measure my power on a long hill.
At the peak of the season a few months ago on 175mm cranks I measured
my output at almost 290 watts by plugging values into
analyticcycling.com. Yesterday with my 195's I calculated over 300
watts, despite having not ridden so much in the last 6 weeks. And it
was pouring rain so my clothes held some unknown mass of water, which
lets me know the output is even a little higher. (My wife gave me one
of those looks when I said I was going to traipse through the house in
sopping wet gear to weigh myself, so the exact weight is unknown for
now...).

I know there are studies showing that crank-length has almost no
bearing on power output, but I think they maybe did not study a wide
enough range. Or perhaps I just am lucky. I haven't been on any rides
longer than 110km with the new cranks, so I don't know how it will play
out endurance-wise.

I think the key is juggling the variables of power (speed), cadence,
and pedal force. The extra leverage afforded by using cranks that are
not drastically undersized allows a lighter force to be applied to
achive a given power at a comfortable cadence. Cadence and force
obviously play into eachother, and when you can't get them to jive, it
isn't strange that it feels funny, or that power is sub-optimal. This
lighter force at least in my case more than makes up for the greater
pedal distance and pedal speed required for a given cadence.

So my new fit seems pretty normal:

seat height (from bb) = (inseam x 1.09) - crank length
seat fore-aft: knee over spindle
cleats: neutral

But it is all only possible by using cranks of length 20.8% of inseam.

Are there many folks using cranks 20.8% of inseam who also have seat
position set similarly, but are of a scale that results in more normal
length cranks like 172.5?

Joseph

wrote:

But the real fun came when I went to measure my power on a long hill.
At the peak of the season a few months ago on 175mm cranks I measured
my output at almost 290 watts by plugging values into
analyticcycling.com. Yesterday with my 195's I calculated over 300
watts, despite having not ridden so much in the last 6 weeks.

I doubt that difference is really significant considering the
variations in wind conditions that always occur... but at least it
looks like you are doing alright with the longer cranks.

I know there are studies showing that crank-length has almost no
bearing on power output, but I think they maybe did not study a wide
enough range.

The ranges are usually quite large... I think 120-220mm in one test
that I recall. Zinn claims that he has many testimonials from people
who love their long cranks... but he has tried to show a positive
correlation with *performance*, and hasn't been able to do so. He also
mentions that he does quite well with 100mm cranks! If you prefer the
"feel" of the long crank, you probably won't be significantly slower at
least.

I think the key is juggling the variables of power (speed), cadence,
and pedal force. The extra leverage afforded by using cranks that are
not drastically undersized allows a lighter force to be applied to
achive a given power at a comfortable cadence. Cadence and force
obviously play into eachother, and when you can't get them to jive, it
isn't strange that it feels funny, or that power is sub-optimal. This
lighter force at least in my case more than makes up for the greater
pedal distance and pedal speed required for a given cadence.

You will have a bigger circle to move your leg around... whether or not
this is "better" than simply pedaling a little faster with the same
force (and a shorter crank), seems to be an individual thing.

Are there many folks using cranks 20.8% of inseam who also have seat
position set similarly, but are of a scale that results in more normal
length cranks like 172.5?

My inseam is 33.5 in (85mm), seat height is 36.25 in (1.08x), and
cranks are 172.5mm (20.3%). If I used 175s I'd be just about there.

I wouldn't mind trying 150s and 190s... just to see what it felt like.

Ron Ruff wrote:
wrote:

But the real fun came when I went to measure my power on a long hill.
At the peak of the season a few months ago on 175mm cranks I measured
my output at almost 290 watts by plugging values into
analyticcycling.com. Yesterday with my 195's I calculated over 300
watts, despite having not ridden so much in the last 6 weeks.

I doubt that difference is really significant considering the
variations in wind conditions that always occur... but at least it
looks like you are doing alright with the longer cranks.

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. It
is of course impossible to say how my fitness has changed, but I'd say
it is safe to say that the 7% power increase was achieved at least to
some degree by the cranks. I don't think it is possible that they
slowed me down, and I am convinced that there is no way I could have
gone as fast with 175's.

I know there are studies showing that crank-length has almost no
bearing on power output, but I think they maybe did not study a wide
enough range.

The ranges are usually quite large... I think 120-220mm in one test
that I recall. Zinn claims that he has many testimonials from people
who love their long cranks... but he has tried to show a positive
correlation with *performance*, and hasn't been able to do so. He also
mentions that he does quite well with 100mm cranks! If you prefer the
"feel" of the long crank, you probably won't be significantly slower at
least.

120-220 sure covers a lot of ground. Perhaps for certain individuals
there are certain lengths that are particularly bad, while most other
lengths are just neutral.

I wasn't expecting my max power to increase, I was hoping to get better
feel and at best flatten out my power-HR curve, if that makes any
sense. I was hoping for more efficient sub-maximum output, ie
endurance. I don't know how one would measure that. Maybe lactate
levels at different power and/or cadences. I intend to take a VOmax and
lactate test later this fall. It is at a place where you use your own
bike. Maybe I'll bring 2 bikes (175, 195) and see how things compare.
Anyone with suggestions on how to measure, or plot this info (and what
info to record) to be able to make sense of it all would be
appreciated.



I think the key is juggling the variables of power (speed), cadence,
and pedal force. The extra leverage afforded by using cranks that are
not drastically undersized allows a lighter force to be applied to
achive a given power at a comfortable cadence. Cadence and force
obviously play into eachother, and when you can't get them to jive, it
isn't strange that it feels funny, or that power is sub-optimal. This
lighter force at least in my case more than makes up for the greater
pedal distance and pedal speed required for a given cadence.

You will have a bigger circle to move your leg around... whether or not
this is "better" than simply pedaling a little faster with the same
force (and a shorter crank), seems to be an individual thing.

I think this is the whole key to it. The individual preference of
relation between force and pedal speed. When one is pedalling along in
a gear that feels too light, why does it feel too light? Likewise what
makes a gear feel too heavy? Somehow 170 seems to have been settled
upon, but why?

Are there many folks using cranks 20.8% of inseam who also have seat
position set similarly, but are of a scale that results in more normal
length cranks like 172.5?

My inseam is 33.5 in (85mm), seat height is 36.25 in (1.08x), and
cranks are 172.5mm (20.3%). If I used 175s I'd be just about there.

Sounds pretty close to me, considering how imprecise inseam measurment
is.


I wouldn't mind trying 150s and 190s... just to see what it felt like.

http://www.hscycle.com/Pages/adjustablecrankset.html

But $450 might be a bit much to satisfy your curiosity...

Joseph

joseph.santanie 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. It

is of course impossible to say how my fitness has changed, but I'd say
it is safe to say that the 7% power increase was achieved at least to
some degree by the cranks. I don't think it is possible that they
slowed me down, and I am convinced that there is no way I could have
gone as fast with 175's.

Lots of variables and uncertainties there. How accurate are the
Analytic Cycling formulas? How accurate were your estimates and
assumptions? How much was due to psychological factors (similar to new
bike syndrome)? And also, you changed several things besides just crank
length. But hey, if it feels more comfortable, and you're riding
better, don't fight it!

Art Harris

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?

wrote in message
oups.com...
Hi Everyone,

I think I have finally settled into a position I am comfortable with
and I hope will allow for maximal power output and maximum efficiency
at sub-maximal power outputs. In other words, improved endurance.

First a summary of my situation, then a description of my "solution"
and thoughts on why it seems to work.

My inseam (varies by time of day, compression of meniscus?) seems to be
95cm, my feet are size 50 (305mm long). When I was in my 20's I weighed
about 93 kg (205 lbs), was rather fit, and didn't have any problems
with comfort even on long rides. I used 177.5mm cranks on my road bike,
180's on the time-trial bike. I used LeMond's inseam x 0.883 for seat
height with a little downward fudge for crank length. Knee slightly
forward of the spindle. Way stretched out with a long top-tube and the
longest Cinelli stem I could find.

After a 10 year hiatus I bought a new bike and started riding again.
Once I got down to 105kg I started experimenting with positioning to
find an optimal setting. My hands had problems with numbness, but I
attibuted that to overweight upper body, and rough pavement. My new
bike had 175mm cranks. As my weight dropped to 100kg, the numbness
persisted, and I figured I had to do something about it. So I moved my
saddle slowly rearward to get weight off my arms, as well as raised the
bars, and moved them rearward. I tried a very large range, and the
numbness improved but did not go away. But pedaling always felt
sub-optimal. Standing was a waste of time, and on flats in a tuck I
kept slipping forward on the saddle. On seated climbs I would ankle
quite a bit and slide my butt bones all the way off the rear of the
saddle. I had my cleats set very neutral, but thought I'd try moving
them back to compensate for my large feet, in an attempt to make my
pedalling feel more normal. I didn't notice any real change except my
monster ankling on steep climbs wasn't as effective.

I became intrigued by the "proportional cranks" argument and set about
thinking how it could benefit me. It didn't take much to convince me
that proportional makes sense, and were worth a try. The difference has
been amazing. It took a while to get the seat height right, and I ended
up trying all sorts of crazy combos until I found what felt right. When
I measured the height it corresposnds to 109% of inseam from seat to
pedal spindle. Coincidently a magic number touted my Ed Burke and
others. I also found my knee was right over the pedal spindle. Another
coincidence factor. Everything seemed to be so "normal" that I tried
moving my cleats back to right under the ball of my foot. Again
everyting seemed to just click. I have a pet theory that the
conventional wisdom of large feet benefiting from reaward cleat
position is just a kludge to overcome what is actually people using
cranks that are too short. The issue isn't large feet, the issue is the
long legs attached to those feet!Now in a tuck I don't side forward,
and ankling up steep climbs I don't slide back at all. I shove back a
bit, but not any more than can be taken up by the slack in flesh. My
bars are slighlty higher than they were relative to the seat (about
1cm) but are now 2cm further forward. My fore-aft balance on the bike
seems much better and the numbness in the hands is gone. And even
standing on climbs feels good. Instead of feeling as though I was
teetering on top of a flag pole, I feel like I get good solid strides.

But the real fun came when I went to measure my power on a long hill.
At the peak of the season a few months ago on 175mm cranks I measured
my output at almost 290 watts by plugging values into
analyticcycling.com. Yesterday with my 195's I calculated over 300
watts, despite having not ridden so much in the last 6 weeks. And it
was pouring rain so my clothes held some unknown mass of water, which
lets me know the output is even a little higher. (My wife gave me one
of those looks when I said I was going to traipse through the house in
sopping wet gear to weigh myself, so the exact weight is unknown for
now...).

I know there are studies showing that crank-length has almost no
bearing on power output, but I think they maybe did not study a wide
enough range. Or perhaps I just am lucky. I haven't been on any rides
longer than 110km with the new cranks, so I don't know how it will play
out endurance-wise.

I think the key is juggling the variables of power (speed), cadence,
and pedal force. The extra leverage afforded by using cranks that are
not drastically undersized allows a lighter force to be applied to
achive a given power at a comfortable cadence. Cadence and force
obviously play into eachother, and when you can't get them to jive, it
isn't strange that it feels funny, or that power is sub-optimal. This
lighter force at least in my case more than makes up for the greater
pedal distance and pedal speed required for a given cadence.

So my new fit seems pretty normal:

seat height (from bb) = (inseam x 1.09) - crank length
seat fore-aft: knee over spindle
cleats: neutral

But it is all only possible by using cranks of length 20.8% of inseam.

Are there many folks using cranks 20.8% of inseam who also have seat
position set similarly, but are of a scale that results in more normal
length cranks like 172.5?

Joseph

Art Harris wrote:
joseph.santanie 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. It

is of course impossible to say how my fitness has changed, but I'd say
it is safe to say that the 7% power increase was achieved at least to
some degree by the cranks. I don't think it is possible that they
slowed me down, and I am convinced that there is no way I could have
gone as fast with 175's.

Lots of variables and uncertainties there. How accurate are the
Analytic Cycling formulas? How accurate were your estimates and
assumptions? How much was due to psychological factors (similar to new
bike syndrome)? And also, you changed several things besides just crank
length. But hey, if it feels more comfortable, and you're riding
better, don't fight it!

It is a well graded 6% road, and I weighed myself in full kit with my
bike before each ride. Assuming that alanyliccycling.com is at least
consistent, the "only" variables are weather, weight, and crank length.
The first 290 run was done before I even thought about larger cranks,
and it was an improvement over 260 watts from earlier in the season. At
the time I was very pumped, so that result was as good as it was going
to get, in other words the 290 wasn't artificially low. The second run
definitely had a positive psychological element from everyting feeling
so right with the longer cranks, but I still think the cranks had a
huge physical effect.

But I'll take it any way I can get it!

Joseph

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

tlarwa wrote:
Well, almost. I have a 33" inseam (838mm) and use a 175 crank, which is
~20.8%. My saddle height is 737mm, which is what your formula works out to
as well, but that is to the top of the seat clamp (or to the saddle rails),
NOT to the top of the saddle surface itself. That dimension is a full 50mm
higher. I can't imagine riding that much lower, if that's what you are
suggesting. Hmmm...


So your distance from pedal spindle to seat-top is about 115% of
inseam? I wouldn't even be able to reach the pedals with a setup like
that. Is your inseam measurment accurate? Are you particularly limber,
such that a very straight knee angle and extended foot isn't a problem?

Joseph

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.



Bob Morris


wrote in message
oups.com...

tlarwa wrote:
Well, almost. I have a 33" inseam (838mm) and use a 175 crank, which is
~20.8%. My saddle height is 737mm, which is what your formula works out
to
as well, but that is to the top of the seat clamp (or to the saddle
rails),
NOT to the top of the saddle surface itself. That dimension is a full
50mm
higher. I can't imagine riding that much lower, if that's what you are
suggesting. Hmmm...


So your distance from pedal spindle to seat-top is about 115% of
inseam? I wouldn't even be able to reach the pedals with a setup like
that. Is your inseam measurment accurate? Are you particularly limber,
such that a very straight knee angle and extended foot isn't a problem?

Joseph