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The importance of crank length to the cyclist.

11 Feb 2013 00:47

FrankDay wrote:Could you give more details as to the beginning wattage and ending wattage and when this occurred in the training cycle?


November 2012 at Oceania Track Cycling Champs in Adelaide. Rider was part of the NZ U19 Track Cycling Team.

February 2013 at New Zealand Elite/U19 Track Cycling Champs.

So both priority events and rider aspired to perform and prepared for both.

30 to 32 mph represents over a calculated 80 watt improvement (408 to 490 watts, about 20%) and 35 to 38 mph increase represents a calculated 168 watt improvement (633 to 801 watts, about a 27% improvement).


But you are holding everything else constant. You would think a former Engineer would know better than that considering it was outdoors.

I am glad your rider saw a 60 watt improvement but that doesn't sound that large compared to a calculated 168 watt improvement.


A wild ar*e guestimated 168 watt improvement. Again you would think a former engineer would know better.

60 watts [color="Magenta"]if everything was held equal[/color] would mean a 27 second improvement in the riders 3000m time which would be a World Record by 3 seconds. So as I said certainly more at play in terms of performance than just power or average speed.

And, it sounds like my technique may somewhat underestimate his real power (or over estimate his aerodynamic shape) because he wrote this: "The trainer is fairly accurate at this power level (500 watts), my best estimate is that its equivalent to at least 30 mph on the track."


Laughable! The Cateye makes a guess on power and does not take into account tyre resistance or changes in friction as the roller heats up under use. Again you would think a former engineer would know this.

You may not like the way I calculated that power improvement but since Holman was a PC skeptic and took the challenge to prove my claims to be false I suspect he was not interested in doing these tests on days that made them look better than they were.


I don't think a 10 year old with a limited understanding of cycling or science would like your guesstimation of power.

If one doesn't have SRM data one has to do something to estimate changes. Because these tests were run by the same person on the same track it seems these are reasonable estimates as to his power improvement.


Did the equation include the temperature for each effort, the wind speed for each effort, the equipment used, the gearing used, the clothing used, did the pacing strategy for each ride stay the same etc. 1000s of confounding variables that show how laughable your claims are. Again you would think a former engineer would know better.

So, how about some more details on that "measly" 60 watt increase your rider saw? :-)


At least I know mine is real. Yours is imagined, and done so badly. I wonder about the quality of the School that taught you engineering.
Hamish Ferguson
coachfergblog.blogspot.co.nz

Smart enough to know a power meter measures power, doesn't improve it :cool:
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11 Feb 2013 01:54

FrankDay wrote:But, the main benefit of going shorter for most is not more power but the ability to get better aerodynamics for the time trialist. How on earth do you do that by "simply getting a powertap wheel and testing power output on one of your bikes with adjustable length cranks."

Further, isn't that essentially what Martin did in his study? It would appear that if he had 2-3 times more subjects in that study he would have reached a statistically significant difference between 145 and 170, what would you be saying then? Anyhow, why do I need to repeat Martin's study with N=1?

We are all different when it comes to how much "evidence" it takes to make us change what we are doing. The lack of convincing evidence either way is all the more reason to discuss a subject. Perhaps such discussions will get some researchers off their bottoms and get some good evidence to definitely answer the question. Until then those who are unwilling to experiment on themselves to see what is best for them are "guessing" as to what is best for them.


Ok then, maybe I made an oversimplification. Why not get a track bike, with a powermeter and adjustable cranks, a HRM, then book some time in the velodrome over several weeks/months.

You will have conditions that are as close to identical as possible and an accurate gauge of distance. From here you should be able to get a good idea of how crank length can effect speed, how power delivery changes with crank length and if heart rate intensity changes with crank length as well.

An experiment like this could really make or break your claims Frank. Why not give it a go?
How to ride like a Tour champion!

proof noun (SHOWING TRUTH)

B2 [C or U] a fact or piece of information that shows that something exists or is true

http://dictionary.cambridge.org/dict...ritish/proof_1


evidence noun [U] uk /ˈev.ɪ.dəns/ us

B2 one or more reasons for believing that something is or is not true

http://dictionary.cambridge.org/dict...itish/evidence
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11 Feb 2013 02:11

42x16ss wrote:Ok then, maybe I made an oversimplification. Why not get a track bike, with a powermeter and adjustable cranks, a HRM, then book some time in the velodrome over several weeks/months.

You will have conditions that are as close to identical as possible and an accurate gauge of distance. From here you should be able to get a good idea of how crank length can effect speed, how power delivery changes with crank length and if heart rate intensity changes with crank length as well.

An experiment like this could really make or break your claims Frank. Why not give it a go?
I don't need to although now that I have a preproduction model of the iCranks I will be able to do this on the Velotron (as I test to see how the iCrank calibration changes with crank length) I will do so and compare power vs HR vs crank length (and be able to look at how the pedal forces change also). Further, one of my elite athletes has his PowerCranks mounted on an SRM hub such that we will be able to do the same validation on an SRM without any chain losses (although I think the Velotron is a little more accurate).

That having been said, this experiment has been done many times by customers who have listened to us and tried this experiment (perhaps not on a track but usually with a power meter). Most (but not all) have decided to stay short and when I hear about the results I regularly post most of those anecdotal reports here. Plus, isn't this essentially what Martin did? Regardless of these many reports (and the Martin study) I haven't seen any of these "making or breaking" the bias of the unbelievers who have never done this experiment themselves.
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11 Feb 2013 02:25

CoachFergie wrote:At least I know mine is real. Yours is imagined, and done so badly. I wonder about the quality of the School that taught you engineering.
Fergie, that report was made by an engineer (worked at Boeing if I remember correctly) who, before he got on the cranks, was just as negative regarding the potential as you. Not everyone has the ability to measure power down to the nanowatt (as if that is important). His reports are his reports, attempts to relate to the group his experience and analysis. My analysis was an attempt to put the overall speed improvements he reported in his final report into perspective for those who do not understand that power generally varies with the CUBE of the speed. Ignore it if you choose.
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11 Feb 2013 02:44

FrankDay wrote:I don't need to although now that I have a preproduction model of the iCranks I will be able to do this on the Velotron (as I test to see how the iCrank calibration changes with crank length) I will do so and compare power vs HR vs crank length (and be able to look at how the pedal forces change also). Further, one of my elite athletes has his PowerCranks mounted on an SRM hub such that we will be able to do the same validation on an SRM without any chain losses (although I think the Velotron is a little more accurate).

That having been said, this experiment has been done many times by customers who have listened to us and tried this experiment (perhaps not on a track but usually with a power meter). Most (but not all) have decided to stay short and when I hear about the results I regularly post most of those anecdotal reports here. Plus, isn't this essentially what Martin did? Regardless of these many reports (and the Martin study) I haven't seen any of these "making or breaking" the bias of the unbelievers who have never done this experiment themselves.

Cool, why don't you request the customer's power files? The data could really back up your marketing. The Martin study was relatively limited, as Hamish and others have discussed. With your customer base (if it is what you are suggesting) you could potentially compile mountains of data...

I also suggested the velodrome so that you can get some idea of the effect crank length can have on overall speed at a given power from an aero point of view.
How to ride like a Tour champion!

proof noun (SHOWING TRUTH)

B2 [C or U] a fact or piece of information that shows that something exists or is true

http://dictionary.cambridge.org/dict...ritish/proof_1


evidence noun [U] uk /ˈev.ɪ.dəns/ us

B2 one or more reasons for believing that something is or is not true

http://dictionary.cambridge.org/dict...itish/evidence
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11 Feb 2013 03:01

42x16ss wrote:Cool, why don't you request the customer's power files? The data could really back up your marketing. The Martin study was relatively limited, as Hamish and others have discussed. With your customer base (if it is what you are suggesting) you could potentially compile mountains of data...

I also suggested the velodrome so that you can get some idea of the effect crank length can have on overall speed at a given power from an aero point of view.
I understand. Actually, we did get some power files and I thought I posted them here, but maybe the guy asked us to keep them to ourselves - I will have to check. Anyhow, he is an elite coach out of Italy and just didn't believe that short cranks could be powerful. I think he tested 175, 165, and 155 and couldn't believe the results (I think the 155 was a little higher).

I understand the Velodrome and aerodynamics thing but this can now be done on a regular bike with a power meter using the Chung technique.

Anyhow, I firmly believe this is something that each person needs to experiment with themselves and see what is best for them. The fact that your bike came with 170 cranks is not good evidence that is the best crank length for you. Neither I nor Fergie, nor you, nor anyone else can predict what anyone else will do. I think I said that in the first post in this thread. If not, I say it now.
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FrankDay
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11 Feb 2013 03:10

FrankDay wrote:Actually, we did get some power files and I thought I posted them here.
Found them.
If the link doesn't work the post was on 10/1/12 and I find it on page 169 on my screen
http://forum.cyclingnews.com/showthread.php?p=1040739&highlight=excaliber#post1040739
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FrankDay
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11 Feb 2013 10:21

FrankDay wrote:Fergie, that report was made by an engineer (worked at Boeing if I remember correctly) who, before he got on the cranks, was just as negative regarding the potential as you. Not everyone has the ability to measure power down to the nanowatt (as if that is important). His reports are his reports, attempts to relate to the group his experience and analysis. My analysis was an attempt to put the overall speed improvements he reported in his final report into perspective for those who do not understand that power generally varies with the CUBE of the speed. Ignore it if you choose.


I will bear that in mind the next time I fly on a Boeing. Bit like the MIT grad who claimed a FTP (60min test) improvement from a rollers based test that was higher than his 20min power from a uphill time trial. Turns out the MIT (isn't that a big deal in the US???) grad hadn't calibrated his power meter. You would expect a MIT grad would know better.

I feel it is you who does not understand what power is and how depending on the environment and mechanical considerations that speed may have no relationship with power. Again you would think a former engineer would know better.
Hamish Ferguson
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Smart enough to know a power meter measures power, doesn't improve it :cool:
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11 Feb 2013 17:29

CoachFergie wrote:I will bear that in mind the next time I fly on a Boeing. Bit like the MIT grad who claimed a FTP (60min test) improvement from a rollers based test that was higher than his 20min power from a uphill time trial. Turns out the MIT (isn't that a big deal in the US???) grad hadn't calibrated his power meter. You would expect a MIT grad would know better.

I feel it is you who does not understand what power is and how depending on the environment and mechanical considerations that speed may have no relationship with power. Again you would think a former engineer would know better.

LOL. MIT actually does have a pretty good reputation here and deservedly so, I think. You don't want to know what that MIT grad thinks of your abilities. You misconstrue and misrepresent almost everything but I think it would be better to stay with the actual data brought up in this thread than personally attack another person not here to defend himself.
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11 Feb 2013 18:07

FrankDay wrote:LOL. MIT actually does have a pretty good reputation here and deservedly so, I think. You don't want to know what that MIT grad thinks of your abilities. You misconstrue and misrepresent almost everything but I think it would be better to stay with the actual data brought up in this thread than personally attack another person not here to defend himself.


Well like your personal attacks on us I don't really care about your opinion or his. If we stick to the facts then crank length isn't all that important. The only person who says it is is the person with a history of starting Spam threads and has an adjustable crank length product to sell.
Hamish Ferguson
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14 Feb 2013 01:37

A new anecdotal report: A local long-time PowerCranker had a problem with his PowerCranks and he came by the office to get it fixed. He has had his PowerCranks for 8 years and has over 100,000 miles on them. We think his is pretty well adapted (He said it took him 18 months to get fully adapted - so much for those 6 week studies). We fixed his issue and then talked to him about trying shorter cranks. It took a lot of talking (he simply couldn't believe shorter could be better) but we convinced him to try a week at 150 and report back, so we set him up and he rode off on 150 cranks. He emailed when he got home that he already loved the 150's as being so much easier on the HF's, especially in the aero position. The real test will be when he climbs Mt Diablo. He is now ready to experiment with 130's. I will let you know what he further reports.
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14 Feb 2013 01:53

FrankDay wrote:A new anecdotal report: A local long-time PowerCranker had a problem with his PowerCranks and he came by the office to get it fixed. He has had his PowerCranks for 8 years and has over 100,000 miles on them. We think his is pretty well adapted (He said it took him 18 months to get fully adapted - so much for those 6 week studies). We fixed his issue and then talked to him about trying shorter cranks. It took a lot of talking (he simply couldn't believe shorter could be better) but we convinced him to try a week at 150 and report back, so we set him up and he rode off on 150 cranks. He emailed when he got home that he already loved the 150's as being so much easier on the HF's, especially in the aero position. The real test will be when he climbs Mt Diablo. He is now ready to experiment with 130's. I will let you know what he further reports.


So what part of that advertorial (aka spam) is meant to provide evidence that crank length is important?

Saying that riders I coach won 21 titles at the Canterbury Track Cycling champs and I attribute it to not paying attention to crank length is just as meaningful a statement.
Hamish Ferguson
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14 Feb 2013 11:39

FrankDay wrote:(He said it took him 18 months to get fully adapted - so much for those 6 week studies). We fixed his issue and then talked to him about trying shorter cranks. It took a lot of talking (he simply couldn't believe shorter could be better) but we convinced him to try a week at 150 and report back, so we set him up and he rode off on 150 cranks. He emailed when he got home that he already loved the 150's as being so much easier on the HF's, especially in the aero position.



When a rider is fully adapted after that 18 months of exclusive PC use, where in the pedaling circle can the PC advantage be found, where does he gain that extra 40% crank torque.
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14 Feb 2013 16:25

coapman wrote:When a rider is fully adapted after that 18 months of exclusive PC use, where in the pedaling circle can the PC advantage be found, where does he gain that extra 40% crank torque.
The advantage, I believe, occurs at every point around the circle. From making the muscle forces more tangential, to increasing forces across the top and bottom, to increasing the unweighting on the backstroke. It isn't one thing, it is lots of small things that add together to become a big thing.
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18 Feb 2013 02:56

FrankDay wrote:You know, if a thread is to be locked "in the name of science" you would only be able to discuss pretty much nothing. . . .

Anyhow, I am somewhat appalled that you, as a moderator, would even consider this request based upon the science. These threads would be much better (I doubt we would be above 100 posts and off the front page a long time ago) if you would simply ban those who only know how to respond with personal attacks. Where is the science there?

. . .Your consideration of this is especially troubling in view of the fact that I have been told that several of the "big boys" either are manufacturing shorter cranks now (Rotor) or expect to soon be manufacturing shorter cranks. Something must be making them do this but, I suspect, it sure as heck is not the naysayers who hang out here. Will you still ban crank length discussions when Shimano starts making 150 mm cranks? Or, is it only my input that is troubling?


No, the question isn't "science" at all. The question is simply this "Is this forum being used to promote or sell a product where the poster has a personal (and financial) interest in selling that product." You are the main poster in two threads, both of which are now more about your product and theories then they are about the thread title. I could, I suppose, close the threads because they have gone hopelessly off-topic. Oddly enough, the other thread you started ("Pedaling technique"), you began with a post where you were correct in saying that the significance was far greater than for just your product. But, that thread degenerated into what is primarily a discussion of your theories and product. And using the forum to spam for a product is, last time I checked, in violation of the TOS.

These two threads are borderline in my thinking at this moment. I am not yet convinced that they are in violation of the TOS.

As for being "appalled" that I would take what a poster says into consideration, would you rather I acted out-of-hand, in a dictatorial fashion? I take everything into consideration - some things get more consideration than others - depending on the credibility of the source, and the reasoning offered. That includes what you have to say.
It is of great use to the sailor to know the length of his line, though he cannot with it fathom all the depths of the ocean. ~ John Locke
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18 Feb 2013 07:27

hiero2 wrote:These two threads are borderline in my thinking at this moment. I am not yet convinced that they are in violation of the TOS.


Both threads start with a little advertorial leading to a link on his commercial site. Smells like SPAM to me. Frank has been banned from other sites like Slowtwitch for doing this.
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18 Feb 2013 13:44

"It's the biggest setback I've ever had in my cycling career*, so it's a new experience for me."
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*collar bone fracture
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18 Feb 2013 18:28

hiero2 wrote:As for being "appalled" that I would take what a poster says into consideration, would you rather I acted out-of-hand, in a dictatorial fashion?


Does anyone ever read and understand what I actually write? The original request by fortysixandtwo was the thread be locked "in the name of science" and you responded as "having a similar thought". Anyhow, back in post 1766 of this thread this is what I said: "Anyhow, I am somewhat appalled that you, as a moderator, would even consider this request based upon the science." In fact, I am probably the only poster who has actually brought science into this discussion as it was a scientific study (Martin) that got me thinking about this subject.
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18 Feb 2013 18:29

CoachFergie wrote:Frank has been banned from other sites like Slowtwitch for doing this.
Really? News to me.
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18 Feb 2013 18:53

FrankDay wrote:In fact, I am probably the only poster who has actually brought science into this discussion as it was a scientific study (Martin) that got me thinking about this subject.


Hilarious. Yet you continually ignore Dr Martin's presentation on crank length and pedalling technique which sums up rather nicely why your claims have no scientific basis. Rather classic was when you said you where only aware of Dr Martins original study on the subject when he has done or been involved in several studies on crank length where no data has been presented that crank length or pedalling technique is of any importance to cycling performance.
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