Ekimov uses 180mm cranks!!!

While at the 2002 Tour......after a stage was able to get up close to Ekimov's bike. While I was
taking a close-up picture of the new "Lance pedal"(new Dura-Ace PD-7750 pedal), which was still
"under wraps" at that time, I noticed he was riding 180mm cranks!! The bike was an off-the-shelf
OCLV, either a 54cm or a 56cm. I ride a 56cm myself, and while standing next to him, I noticed him
to be a little shorter than myself, I'm 5'10".

Aren't 180mm cranks like......super long for a guy that stands about 5'8" or 9", and rides a 54
or 56cm bike?? The stage a flat road stage.

Are super long cranks common for pros in stage races? Or is Ekimov just a freak?

Thanks, Alexi G.

 

That is very long for a guy his size. 180s are the size Indurain used, and he was about 6'3" if I
recall correctly. I'm about that size (5'9") and I ride 175s, which some people would consider long
for a rider my size. But it really has more to do with the length of your inseam than your height.

I'm going to guess he's riding those for one of two reasons:

1) He has Indurain-length legs. (unlikely)
2) He beleives the longer cranks give him better leverage on climbs.

I'm guessing its the second. Its like when you're trying to get a tough, rusty bolt loose you break
out the longer wrench... more of a mechanical advantage.

The drawback to this is that you have move your feet in bigger circles, which could be a
disadvantage in itself from a fatigue standpoint. I'm not sure if anyone has ever done any studies
on this, but I think it would be pretty straight forward to figure out.

Anyone?

- Boyd S.

[email protected] (AlexiG) wrote in news:[email protected]:

> While at the 2002 Tour......after a stage was able to get up close to Ekimov's bike. While I was
> taking a close-up picture of the new "Lance pedal"(new Dura-Ace PD-7750 pedal), which was still
> "under wraps" at that time, I noticed he was riding 180mm cranks!! The bike was an off-the-shelf
> OCLV, either a 54cm or a 56cm. I ride a 56cm myself, and while standing next to him, I noticed him
> to be a little shorter than myself, I'm 5'10".
>
> Aren't 180mm cranks like......super long for a guy that stands about 5'8" or 9", and rides a 54
> or 56cm bike?? The stage a flat road stage.
>
> Are super long cranks common for pros in stage races? Or is Ekimov just a freak?
>
> Thanks, Alexi G.

 

Zinn did a "study" for Velo News a few years ago. He managed to come up with some interesting ideas
about crank lengths but I don't remember what they were. Anyone?

"Boyd Speerschneider" <[email protected]> wrote in message
news:[email protected]...
> That is very long for a guy his size. 180s are the size Indurain used, and he was about 6'3" if
> I recall correctly. I'm about that size (5'9") and I ride 175s, which some people would
> consider long for a rider my size. But it really has more to do with the length of your inseam
> than your height.
>
> I'm going to guess he's riding those for one of two reasons:
>
> 1) He has Indurain-length legs. (unlikely)
> 2) He beleives the longer cranks give him better leverage on climbs.
>
> I'm guessing its the second. Its like when you're trying to get a tough, rusty bolt loose you
> break out the longer wrench... more of a mechanical advantage.
>
> The drawback to this is that you have move your feet in bigger circles, which could be a
> disadvantage in itself from a fatigue standpoint. I'm not sure if anyone has ever done any studies
> on this, but I think it would be pretty straight forward to figure out.
>
> Anyone?
>
> - Boyd S.
>
> [email protected] (AlexiG) wrote in news:[email protected]:
>
> > While at the 2002 Tour......after a stage was able to get up close to Ekimov's bike. While I was
> > taking a close-up picture of the new "Lance pedal"(new Dura-Ace PD-7750 pedal), which was still
> > "under wraps" at that time, I noticed he was riding 180mm cranks!! The bike was an off-the-shelf
> > OCLV, either a 54cm or a 56cm. I ride a 56cm myself, and while standing next to him, I noticed
> > him to be a little shorter than myself, I'm 5'10".
> >
> > Aren't 180mm cranks like......super long for a guy that stands about 5'8" or 9", and rides a
> > 54 or 56cm bike?? The stage a flat road stage.
> >
> > Are super long cranks common for pros in stage races? Or is Ekimov just a freak?
> >
> > Thanks, Alexi G.

 

His tests did not allow for a significant adaptation period. He found the only trend he should spot
was that the cranks at both extreme in length seemed to be the best for optimal power. His testing
was flawed.

Another (AIS, I think) group studied crank length and allowed each subject more than 4 weeks to
adapt to the crank they each tested. In these tests, the trend was towards longer cranks than what
is traditionally recommended.

When I switched to 180, it took me several months before I could apply full power without risk
of straining muscles. I could spin just fine, but I would get sore if I worked too hard before I
was accustomed to them. It seems the longer cranks utilize muscle tissue not used with the
shorter cranks.

The bottom line is, if you have the opportunity to try a few cranks out, you will probably settle on
cranks that are shorter than optimal. If you allow yourself time to adapt before you apply full
torque, you will come up with more power without compromising your high cadence.

"Mike S." <[email protected]> wrote in message news:[email protected]...
> Zinn did a "study" for Velo News a few years ago. He managed to come up with some interesting
> ideas about crank lengths but I don't remember what they were. Anyone?
>
>
> "Boyd Speerschneider" <[email protected]> wrote in message
> news:[email protected]...
> > That is very long for a guy his size. 180s are the size Indurain used, and he was about 6'3" if
> > I recall correctly. I'm about that size (5'9") and I ride 175s, which some people would consider
> > long for a rider my size. But it really has more to do with
the
> > length of your inseam than your height.
> >
> > I'm going to guess he's riding those for one of two reasons:
> >
> > 1) He has Indurain-length legs. (unlikely)
> > 2) He beleives the longer cranks give him better leverage on climbs.
> >
> > I'm guessing its the second. Its like when you're trying to get a tough, rusty bolt loose you
> > break out the longer wrench... more of a mechanical advantage.
> >
> > The drawback to this is that you have move your feet in bigger circles, which could be a
> > disadvantage in itself from a fatigue standpoint. I'm not sure if anyone has ever done any
> > studies on this, but I think it would be pretty straight forward to figure out.
> >
> > Anyone?
> >
> > - Boyd S.
> >
> > [email protected] (AlexiG) wrote in news:[email protected]:
> >
> > > While at the 2002 Tour......after a stage was able to get up close to Ekimov's bike. While I
> > > was taking a close-up picture of the new "Lance pedal"(new Dura-Ace PD-7750 pedal), which was
> > > still "under wraps" at that time, I noticed he was riding 180mm cranks!! The bike was an
> > > off-the-shelf OCLV, either a 54cm or a 56cm. I ride a 56cm myself, and while standing next to
> > > him, I noticed him to be a little shorter than myself, I'm 5'10".
> > >
> > > Aren't 180mm cranks like......super long for a guy that stands about 5'8" or 9", and rides
> > > a 54 or 56cm bike?? The stage a flat road stage.
> > >
> > > Are super long cranks common for pros in stage races? Or is Ekimov just a freak?
> > >
> > > Thanks, Alexi G.
> > >
> >

 

As much as I like Lennard Zinn, I think that even he would admit that his attempts to address the
issue were limited at best.

Here are links to what is presently probably the definitive research on the subject:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_ui
ds=10828327&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_ui
ds=11417428&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_ui
ds=12183473&dopt=Abstract

Andy Coggan (back on 170s, thanks to Jim)

"Mike S." <[email protected]> wrote in message news:[email protected]...
> Zinn did a "study" for Velo News a few years ago. He managed to come up with some interesting
> ideas about crank lengths but I don't remember what they were. Anyone?
>
>
> "Boyd Speerschneider" <[email protected]yahoo.com> wrote in message
> news:[email protected]...
> > That is very long for a guy his size. 180s are the size Indurain used, and he was about 6'3" if
> > I recall correctly. I'm about that size (5'9") and I ride 175s, which some people would consider
> > long for a rider my size. But it really has more to do with
the
> > length of your inseam than your height.
> >
> > I'm going to guess he's riding those for one of two reasons:
> >
> > 1) He has Indurain-length legs. (unlikely)
> > 2) He beleives the longer cranks give him better leverage on climbs.
> >
> > I'm guessing its the second. Its like when you're trying to get a tough, rusty bolt loose you
> > break out the longer wrench... more of a mechanical advantage.
> >
> > The drawback to this is that you have move your feet in bigger circles, which could be a
> > disadvantage in itself from a fatigue standpoint. I'm not sure if anyone has ever done any
> > studies on this, but I think it would be pretty straight forward to figure out.
> >
> > Anyone?
> >
> > - Boyd S.
> >
> > [email protected] (AlexiG) wrote in news:[email protected]:
> >
> > > While at the 2002 Tour......after a stage was able to get up close to Ekimov's bike. While I
> > > was taking a close-up picture of the new "Lance pedal"(new Dura-Ace PD-7750 pedal), which was
> > > still "under wraps" at that time, I noticed he was riding 180mm cranks!! The bike was an
> > > off-the-shelf OCLV, either a 54cm or a 56cm. I ride a 56cm myself, and while standing next to
> > > him, I noticed him to be a little shorter than myself, I'm 5'10".
> > >
> > > Aren't 180mm cranks like......super long for a guy that stands about 5'8" or 9", and rides
> > > a 54 or 56cm bike?? The stage a flat road stage.
> > >
> > > Are super long cranks common for pros in stage races? Or is Ekimov just a freak?
> > >
> > > Thanks, Alexi G.
> > >
> >

 

I suppressed wordwrap from Andrew Coggan's post, to keep these URL's intact. http://www.ncbi.nlm.ni-
h.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10828327&dopt=Abstract http://www.ncbi.nlm-
.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11417428&dopt=Abstract http://www.ncbi.-
nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12183473&dopt=Abstract

My summary interpretation -- muscular efficiency is determined by the pedal velocity, and thus
whatever the crank length, one can simply adjust the gear to suit. However, peak muscular power is
optimized for a particular crank length, representing 20% of leg length or 41% of tibia length,
although the curve is broad.

Still not addressed, however, is the issue of comfort. I believe in real-world situations, results
may differ from those in the lab, due to the influence of psychology on motivation. In the lab,
someone tells you to ride 250 watts, you do it, and no more. In the real world, you ride at a power
level which is psychologically sustainable. This can be perhaps affected by comfort, which may be
affected by crank length.

Nevertheless, the results are compelling.

Dan

 

Chris M wrote:
> His tests did not allow for a significant adaptation period. He found the only trend he should
> spot was that the cranks at both extreme in length seemed to be the best for optimal power. His
> testing was flawed.
>
> Another (AIS, I think) group studied crank length and allowed each subject more than 4 weeks to
> adapt to the crank they each tested. In these tests, the trend was towards longer cranks than what
> is traditionally recommended.
>
> When I switched to 180, it took me several months before I could apply full power without risk
> of straining muscles. I could spin just fine, but I would get sore if I worked too hard before I
> was accustomed to them. It seems the longer cranks utilize muscle tissue not used with the
> shorter cranks.
>
>
> The bottom line is, if you have the opportunity to try a few cranks out, you will probably settle
> on cranks that are shorter than optimal. If you allow yourself time to adapt before you apply full
> torque, you will come up with more power without compromising your high cadence.

First, the last statement is incompatible with Jim Martin's paper, cited by Andrew Coggan -- cadence
at peak power IS reduced by crank length. But that's not important.

Second, there is another issue -- cornering clearance. While in principle bottom bracket height can
be adjusted, in practice this is usually impractical. I like knowing others will plant their pedals
before I will going into a corner. Given the broad peak of peak power on crank length, this can
easily shift the optimum 5mm, for mass-start racing, IMO.

Dan

 

"Daniel Connelly" <[email protected]> wrote in message news:[email protected]...
>
> there is another issue -- cornering clearance. While in principle bottom bracket height can be
> adjusted, in practice this is usually impractical.
I like
> knowing others will plant their pedals before I will going into a corner.
Given
> the broad peak of peak power on crank length, this can easily shift the
optimum
> 5mm, for mass-start racing, IMO.

And even for solo events (i.e., time trials), where cornering clearance is rarely an issue, shorter
cranks may still be preferable, in that they may allow you to comfortably acheive a lower, more
aerodynamic position.

Andy Coggan

 

"Boyd Speerschneider" <[email protected]> wrote in message
news:[email protected]...
> That is very long for a guy his size. 180s are the size Indurain used, and he was about 6'3" if I
> recall correctly.

6'2" I think but tall nevertheless.

> I'm going to guess he's riding those for one of two reasons:
>
> 1) He has Indurain-length legs. (unlikely)
> 2) He beleives the longer cranks give him better leverage on climbs.

Ekimov made his mark by being the fastest pursuiter around. He has a lower cadence than some and
carries a big gear. You might even say that he's an anti-Lance. Yet he was the World Champion in the
TT one year. It's really hard to argue with success.

 

"Mike S." <[email protected]> wrote in message news:[email protected]...
> Zinn did a "study" for Velo News a few years ago. He managed to
come up
> with some interesting ideas about crank lengths but I don't remember
what
> they were. Anyone?

When he was testing short cranks everyone preformed better on short cranks than on normal ones. When
he was testing long cranks everyone performed better on long cranks (even a woman that normally used
165's) than on normal cranks.

Sounds to me like you can't get comprehensive information in a test like that.

 

Phil Holman wrote:

>
> We tend not to argue with it but try to understand why it doesn't apply to everyone.
>
> Phil Holman

You people,

It's not going to do any good trying to "understand" it when all these "studies" are erroneously
reducing the biomechanical ergonomics and physiology of the cyclists' legs as being defined by
leg length.

Citing studies that assume that everyone who is a certain height or has a certain leg length has the
same muscle insertions, tendon attachments, underlying physiology, etc. of their leg introduces huge
error factors. The fact is, there is tremendous variation in absolute strength, speed, wattage
output, and endurance of people with the SAME leg length that would allow certain riders of the same
leg length to do better using DIFFERENT crank arm lengths.

I don't see where any of these studies make a distinction between the leg physiology of a 6'0"
marathoner verses a 6'0" sprinter with identical leg lengths. All these studies would seem to end up
recommending the same crank arm length based merely on equal leg length.

Consequently, all of these studies are far more flawed than you think, and not just because Mr. Zinn
forgot to allow for adpatation to take place.

The reality is the best crank arm length for a rider must be measured individually, and cannot ever
be extrapolated from studies done on other people. Even if you did mean wattage output of many
cyclists with the same leg length, the result would be off for any given rider who might be at the
extreme end of the bell curve and would therefore benefit more from using a correspondingly extreme
crank arm length.

Carl Lewis would likely benefit from using a different crank arm length and cadence than a
marathoner of identical leg length. To assume he should use the same crank arm length as a
marathoner just because they both have the same leg length is clueless.

So you people are trying to fit square pegs in round holes when you make one of the variables "leg
length" instead of leg physiology and leg ergonomics.

You people aren't that smart after all,

Café

 

"Café de Colombia" <[email protected]> wrote in message news:[email protected]...
> Phil Holman wrote:
>
> >
> > We tend not to argue with it but try to understand why it doesn't apply
to
> > everyone.
> >
> > Phil Holman
>
> You people,
>
> It's not going to do any good trying to "understand" it when all these
"studies" are erroneously reducing the
> biomechanical ergonomics and physiology of the cyclists' legs as being
defined by leg length.
>
> Citing studies that assume that everyone who is a certain height or has a
certain leg length has the same muscle
> insertions, tendon attachments, underlying physiology, etc. of their leg
introduces huge error factors. The fact is,
> there is tremendous variation in absolute strength, speed, wattage output,
and endurance of people with the SAME leg
> length that would allow certain riders of the same leg length to do better
using DIFFERENT crank arm lengths.
>
> I don't see where any of these studies make a distinction between the leg
physiology of a 6'0" marathoner verses a 6'0"
> sprinter with identical leg lengths. All these studies would seem to end
up recommending the same crank arm length
> based merely on equal leg length.
>
> Consequently, all of these studies are far more flawed than you think, and
not just because Mr. Zinn forgot to allow
> for adpatation to take place.
>
> The reality is the best crank arm length for a rider must be measured
individually, and cannot ever be extrapolated
> from studies done on other people. Even if you did mean wattage output of
many cyclists with the same leg length, the
> result would be off for any given rider who might be at the extreme end of
the bell curve and would therefore benefit
> more from using a correspondingly extreme crank arm length.
>
> Carl Lewis would likely benefit from using a different crank arm length
and cadence than a marathoner of identical leg
> length. To assume he should use the same crank arm length as a marathoner
just because they both have the same leg
> length is clueless.
>
> So you people are trying to fit square pegs in round holes when you make
one of the variables "leg length" instead of
> leg physiology and leg ergonomics.
>
> You people aren't that smart after all,

And apparently neither are you: in studying maximal power, Jim in fact did find weak but significant
correlations between optimal crank length and leg or tibia length. Perhaps these correlations would
have been greater had if actual muscle lengths been used. *However, that would not change the fact
the effects of crank length on maximal power were trivial at best.* IOW, a given rider generated
essentially the same maximal power on cranks that varied markedly in length. Since their muscle
lengths didn't change, that means there is little *functional* relationship between muscle length,
crank length, and maximal power, regardless of how you express the data. Indeed, this is exactly
what you would expect, given that the force-length relationship of muscle shows a broad plateau at
the sarcomeric level.

Now tell me something new, Cafe' de Crackhead,

Andy Coggan

 

[email protected] (AlexiG) wrote in message
news:<[email protected]>...
> While at the 2002 Tour......after a stage was able to get up close to Ekimov's bike. While I was
> taking a close-up picture of the new "Lance pedal"(new Dura-Ace PD-7750 pedal), which was still
> "under wraps" at that time, I noticed he was riding 180mm cranks!! The bike was an off-the-shelf
> OCLV, either a 54cm or a 56cm. I ride a 56cm myself, and while standing next to him, I noticed him
> to be a little shorter than myself, I'm 5'10".
>
> Aren't 180mm cranks like......super long for a guy that stands about 5'8" or 9", and rides a 54
> or 56cm bike?? The stage a flat road stage.
>
> Are super long cranks common for pros in stage races? Or is Ekimov just a freak?
>
> Thanks, Alexi G.

BiciSport used to publish extensive data on various riders bikes. Leoni is still riding, I believe.
It noted that Indurain SOMETIMES used 180 mm cranks.

For what it's worth, heres some data circa 1993:

Rider Height Inseam Frame c-c Rings Length Bugno 5-9 34 56 41/53 172.5 Kelly 5-10 33.5 56 42/52
172.5 Guippomi 5-8 32.7 54.5 41/53 170 Argentin 5-8 32.3 52.5 41/53 170 Leoni 5-9 31.1 54 41/53 170
Breukink 6-3/4 33.9 56 42/53 172.5

I was suprised how small the frames are. Example Breukink who is over 6 feet yet rides a 56 cm
frame. Everybody used longish stems, 11-12 cm, and 42 cm bars or wider. Indurain was listed at 6-2
with huge 180 mm cranks on one of his bikes on a 59 c-c frame.

I would have thought Guipponi was taller than 5-8 from looking at old photos.....

Note the lack of 39 rings (at least at this race) and Kelly using a 52 ring.

 

"Andy Coggan" <[email protected]> wrote in message
news:<[email protected]>...
>
> Now tell me something new, Cafe' de Crackhead,

I have to admit that is a funny line Andy.

 

"Café de Colombia" wrote:
> The reality is the best crank arm length for a rider must be measured
individually

I think Columbian Coffee may be onto something here. Also, optimum crank arm length might also vary
depending on application. TT bike, Crit bike, RR bike, Mountain bike, track bike, etc.

--
Bill

 

"BBC3" <[email protected]> wrote in message news:<%[email protected]>...
> "Café de Colombia" wrote:
> > The reality is the best crank arm length for a rider must be measured
> individually
>
> I think Columbian Coffee may be onto something here. Also, optimum crank arm length might also
> vary depending on application. TT bike, Crit bike, RR bike, Mountain bike, track bike, etc.

I'm not surprised you posted this after Coggan really had the last word.

 

Andy Coggan wrote:

> "Stewart Fleming" <[email protected]> wrote in message news:[email protected]...
> > - increase crank length by 5mm and put on a ring one tooth bigger than normal = reduced force
> > required on pedals, equates to reduced power required to maintain same speed OR increased
> > speed for same power if same force is applied to pedals as for shorter cranks/smaller ring
> > (Eddie B)
>
> It's voodoo, alright: the power required to overcome wind resistance, etc., is completely
> independent of crank length. So, the only question at hand is

That's not what I wrote to summarize the old wisdom. I'm referring to power _input_ ie. force on the
pedal. It's from _Bicycle Road Racing_, p196 where he reproduces an _old_ (I didn't say this was
recent bicycle voodoo either) table from a Soviet study in 1977.

It says that if the cadence and gear ration remain the same, it takes less power to maintain road
speed as crank arm length increases. For example, from the table: for a 91inch gear (54x16 say) at
120rpm (equates to 51kph near enough), 175mm cranks need 6% less force applied to the pedals than
165mm cranks. So since the cadence is the same and the force is less, less power is _required_ from
the rider to maintain the same speed.

Maybe that study needs to be reproduced - it appears that you have different opinions based on more
recent data.

>
> what effect, if any, differences in crank length and hence range of motion has upon power output.
> As Jim Martin's data show, the answer is practically none.
>
> > - height is less important than width in terms of frontal area (John Cobb)
>
> Height (stature) is actually the most significant factor determining frontal area, more important
> than mass, acromion width, etc. For a rider of a given

No, not stature. Height as in maximum height of the rider in position on the bicycle. To put it
another way, if you can't get low, get comfortable and don't worry about a higher position, worry
about a wider position on the bars. Botero in the TdF ITT was a case in point. Armstrong's slightly
higher position is another.

STF

 

"Stewart Fleming" <[email protected]> wrote
>
>
> Andy Coggan wrote:
>
> > "Stewart Fleming" <[email protected]> wrote
> > > - increase crank length by 5mm and put on a ring one tooth bigger than normal = reduced force
> > > required on pedals, equates to reduced power required to maintain same speed OR increased
> > > speed for same power if same force is applied to pedals as for shorter cranks/smaller ring
> > > (Eddie B)
> >
> > It's voodoo, alright: the power required to overcome wind resistance,
etc.,
> > is completely independent of crank length. So, the only question at hand
is
>
> That's not what I wrote to summarize the old wisdom. I'm referring to
power
> _input_ ie. force on the pedal. It's from _Bicycle Road Racing_, p196
where he
> reproduces an _old_ (I didn't say this was recent bicycle voodoo either)
table
> from a Soviet study in 1977.
>
> It says that if the cadence and gear ration remain the same, it takes less
power
> to maintain road speed as crank arm length increases. For example, from the table: for a 91inch
> gear (54x16 say) at 120rpm
(equates to
> 51kph near enough), 175mm cranks need 6% less force applied to the pedals
than
> 165mm cranks. So since the cadence is the same and the force is less,
less
> power is _required_ from the rider to maintain the same speed.
>
> Maybe that study needs to be reproduced - it appears that you have
different
> opinions based on more recent data.

Yikes. "1977 Soviet study," huh? I think that rather than reproduce that study (I don't think
getting more recent data would matter) we should create an archive of these things. One could devote
an entire chapter to Eddie B. himself.

 

"Stewart Fleming" <[email protected]> wrote in message
news:[email protected]...
>
>
> Andy Coggan wrote:
>
> > "Stewart Fleming" <[email protected]> wrote in message news:[email protected]...
> > > - increase crank length by 5mm and put on a ring one tooth bigger than normal = reduced force
> > > required on pedals, equates to reduced power required to maintain same speed OR increased
> > > speed for same power if same force is applied to pedals as for shorter cranks/smaller ring
> > > (Eddie B)
> >
> > It's voodoo, alright: the power required to overcome wind resistance,
etc.,
> > is completely independent of crank length. So, the only question at hand
is
>
> That's not what I wrote to summarize the old wisdom. I'm referring to
power
> _input_ ie. force on the pedal. It's from _Bicycle Road Racing_, p196
where he
> reproduces an _old_ (I didn't say this was recent bicycle voodoo either)
table
> from a Soviet study in 1977.
>
> It says that if the cadence and gear ration remain the same, it takes less
power
> to maintain road speed as crank arm length increases. For example, from the table: for a 91inch
> gear (54x16 say) at 120rpm
(equates to
> 51kph near enough), 175mm cranks need 6% less force applied to the pedals
than
> 165mm cranks. So since the cadence is the same and the force is less,
less
> power is _required_ from the rider to maintain the same speed.

Power is force times distance divided by time. An increase in crank length does result in a decline
in force, but the distance the pedal travels increases correspondingly, such that the power remains
the same. Indeed, this has to be true, since power input into the system (pedals) by the rider must
equal the power required to overcome the sum of all resistive forces at that velocity - if not, you
will either speed up or slow down.

Changing crank length at a fixed cadence* changes two, and only two, things: first, it increases
the velocity of muscle shortening, since the pedals are traveling a greater distance. This effect
is no different than changing gears. Second, it increases the distance over which the muscles
shorten. The latter effect could potentially influence physiological function, but again based on
Jim's data, does not appear to do so significantly even over a wide (by cyclist's standards) range
of crank lengths.

*In fact, I believe that this is an artifactual scenario: increasing crank length tends to result in
a decline in self-selected cadence, probably to keep tangential pedal speed and hence muscle
shortening velocity constant. This probably explains in part the misconception that longer cranks
allow you to "pull a bigger gear"..

Andy Coggan

 

[email protected] (brian roth) wrote in message
news:<[email protected]>...
> [email protected] (AlexiG) wrote in message
> news:<[email protected]>...
> >
> > Aren't 180mm cranks like......super long for a guy that stands about 5'8" or 9", and rides a
> > 54 or 56cm bike?? The stage a flat road stage.
>
> BiciSport used to publish extensive data on various riders bikes. Leoni is still riding, I
> believe. It noted that Indurain SOMETIMES used 180 mm cranks.
>
> For what it's worth, heres some data circa 1993:
>
> Rider Height Inseam Frame c-c Rings Length Bugno 5-9 34 56 41/53 172.5 Kelly 5-10 33.5 56 42/52
> 172.5 Guippomi 5-8 32.7 54.5 41/53 170 Argentin 5-8 32.3 52.5 41/53 170 Leoni 5-9 31.1 54 41/53
> 170 Breukink 6-3/4 33.9 56 42/53 172.5
>
> I was suprised how small the frames are. Example Breukink who is over 6 feet yet rides a 56 cm
> frame. Everybody used longish stems, 11-12 cm, and 42 cm bars or wider. Indurain was listed at 6-2
> with huge 180 mm cranks on one of his bikes on a 59 c-c frame.

It seems to me that Breukink's Tour bike which was for sale at the old Wheelsmith shop in Palo Alto
was a 57 or a 58. I looked pretty closely at buying it at the time. Way too small for me but I could
have forced it with a long stem and setting the seat high and way back. And it would have been the
self-same bike of a genuine Tour hero.

> Note the lack of 39 rings (at least at this race) and Kelly using a 52 ring.

Lance has changed that as has the selection of some really nasty climbs in the grand tours.