The importance of crank length to the cyclist.

[FrankDay]

It's already been done, scientifically, using high frequency data loggers For speed measurement (i.e. not an ordinary bike speed recorder), and that's possibly what Andy is referring to as demonstrating less precision.

Indoor coast down testing:
Candau et al. Med Sci Sports Exerc 1999; 31:1441-1447.

Outdoor coastdown testing:
Cameron. Human Power 1995; 12:7-11

Outdoor testing in particular showed a high Coefficient of Variation, certainly when compared to what's possible when field testing with a power meter.

The question isn't whether one can get increased precision but whether that increased precision makes any difference in outcome.

In my car my speedometer could have 1000, 100, 10, 5, 1, .1, .01 increments in the speed display. Each is more precise than the last yet, at some point that increased precision is not going to help me avoid a speeding ticket better than the last increment.

So, when it comes to measuring effort we have three methods (perceived exertion, HR, power monitors) each one supposedly "more precise" than the earlier one and, of course, power monitors come in different levels of precision themselves. The question is does the increased precision make any difference in outcome to the athlete. There certainly is not data that says definitively yes and one can even argue that "precision" can actually slow the rider down (but no proof to that contention also).

There is no debate that a GM increases precision. The debate (at least as far as I am concerned) is over whether having improved precision here actually makes a positive difference in outcome.

Edit: I guess we have 4 methods. Forgot speedometers, probably the least precise of all, at least outside.

 

[CoachFergie]

The question isn't whether one can get increased precision but whether that increased precision makes any difference in outcome.

The question is whether a difference actually happened. In the case of Drew there is currently no evidence that a difference in performance happened.

In my car my speedometer could have 1000, 100, 10, 5, 1, .1, .01 increments in the speed display. Each is more precise than the last yet, at some point that increased precision is not going to help me avoid a speeding ticket better than the last increment.

And we can record power every 10seconds, 5seconds, 2 seconds, 1 second and every .1 seconds yet neither doing this on the bike or in the car will have the slightest effect on performance.

There is no debate that a GM increases precision. The debate (at least as far as I am concerned) is over whether having improved precision here actually makes a positive difference in outcome.

Keep repeating the lie.

A measurement tool is meant to measure and a performance enhancement method is meant to enhance performance.

Power output is a measure of work performed. Heart rate, RPE and speed are all responses to work performed. If you increase wattage you are doing more work. The same can not be said about heart rate where you can do more work at a lower heart rate if efficiency improves or at higher heart rate if your tolerance improves and heart rate, RPE and speed are all affected by weather and other factors.

Edit: I guess we have 4 methods. Forgot speedometers, probably the least precise of all, at least outside.

Indoors as well. I (and I am sure so does Andy and Alex) have real data that it is affected even indoors by a variety of factors. But indoors these are more easily controlled for.

You could work it all out on the various online calculators available or just do a simple download from a power meter.

 

[CoachFergie]

And, I especially remember his relating coaches claimed science based postings to some other relationships that seemed to be an expression of his frustration, the part that I remember as being particularly funny. (Fergie being as close to being a scientist as an alchemist is to being a chemist, and others.)

What's unscientific about expecting extra-ordinary claims to be supported with valid and reliable data.

WRT wannabe. Isn't that what every student is?

Frank, your barrage of personal insults have no influence on me. It's just another tactic of the Snake Oil Salesman to attack the sender of the message when you know the message is right.

Perhaps I missed the "crossing the line" invective in view of what gets thrown my way, especially by Fergie, that doesn't seem to cross "the" line. I have always wondered if any line ever existed here in view of what I get called. Now that I know there is one I still don't have a clue where it is.

The line for me is when people lie and keep repeating the lie as if they keep saying it others resistance will break and accept it.

Back on topic. 600+ posts and no evidence to support short cranks.

 

[oldborn]

Imagine all the people
Living for today...huuup

 

[twothirds]

He's gonna need some pretty short cranks as his gut is going to affect how high he can bring his knees up

 

[Alex Simmons/RST]

The question isn't whether one can get increased precision but whether that increased precision makes any difference in outcome.

In my car my speedometer could have 1000, 100, 10, 5, 1, .1, .01 increments in the speed display. Each is more precise than the last yet, at some point that increased precision is not going to help me avoid a speeding ticket better than the last increment.

So, when it comes to measuring effort we have three methods (perceived exertion, HR, power monitors) each one supposedly "more precise" than the earlier one and, of course, power monitors come in different levels of precision themselves. The question is does the increased precision make any difference in outcome to the athlete. There certainly is not data that says definitively yes and one can even argue that "precision" can actually slow the rider down (but no proof to that contention also).

There is no debate that a GM increases precision. The debate (at least as far as I am concerned) is over whether having improved precision here actually makes a positive difference in outcome.

Edit: I guess we have 4 methods. Forgot speedometers, probably the least precise of all, at least outside.

Since you are claiming benefits of an approach that includes improved aerodynamics, then yes, in this case the precision of the test method matters because you need the level of precision provided by a power meter (or a good wind tunnel) to demonstrate whether in fact the benefit actually exists.

This is especially so given the cubic equation that represents the relationship between speed and power.

Your comment on measures of effort is a strawman, unrelated to the response which was specifically about testing method for aerodynamic benefit.

 

[FrankDay]

Since you are claiming benefits of an approach that includes improved aerodynamics, then yes, in this case the precision of the test method matters because you need the level of precision provided by a power meter (or a good wind tunnel) to demonstrate whether in fact the benefit actually exists.

This is especially so given the cubic equation that represents the relationship between speed and power.

Your comment on measures of effort is a strawman, unrelated to the response which was specifically about testing method for aerodynamic benefit.

1. I mention the GM as an effort feedback device because that is how the vast majority of owners actually use the device.

2. While I would admit that the chung technique is probably quite reliable and useful in giving an aerodynamic drag number similar to what can be achieved in a wind tunnel again it has never been "proven" that such precision actually in this testing situation actually results in race improvement. For instance.

How many people who own a GM actually know it can be used for this purpose? My guess is less than 1%.

Of those who know of this use, how many do you think have done so? My guess, less than 10%.

Of those who have done this test, how many do you think have done it in such a way that the number received is reliable and accurate? I would be surprised if it were as high as 50%.

Of those who have run the test, how many do you think have made multiple runs, changing position or equipment to optimize aerodynamics. My guess, not very many.

So, of those who own this amazing aerodynamic measuring device, what do you think the average aerodynamic improvement the average user has seen because of their ownership of this device? Not much I suspect.

Photovoltaic cells have the potential to eliminate the US need for imported oil but so far, they have had little impact along those lines. Computers can design life saving molecules for medicine but most people use them for email and personal entertainment (including hanging out in internet forums). I could say the same about my own product. What is one of the more common ways a GM owner use to improve their aerodynamics? I would submit they post a picture to the internet and ask others to critique their position. The fact that something can do something doesn't mean that it is regularly used to its potential.

So, if you have some evidence that the potential of this device to do all these wondrous things actually pans out in the real world with real world improvements of any significance. It doesn't seem like much of a justification for the average person to purchase a GM if the only real benefit of the device is something they will never do.

 

[FrankDay]

Since you are claiming benefits of an approach that includes improved aerodynamics, then yes, in this case the precision of the test method matters because you need the level of precision provided by a power meter (or a good wind tunnel) to demonstrate whether in fact the benefit actually exists.

This is especially so given the cubic equation that represents the relationship between speed and power.

Your comment on measures of effort is a strawman, unrelated to the response which was specifically about testing method for aerodynamic benefit.

I am claiming benefits in aerodynamics using short cranks that come pretty much automatically, no need for any testing. That doesn't mean that the benefits couldn't be improved by serious testing.

1. I mention the GM as an effort feedback device because that is how the vast majority of owners actually use the device.

2. While I would admit that the chung technique is probably quite reliable and useful in giving an aerodynamic drag number similar to what can be achieved in a wind tunnel again it has never been "proven" that such precision actually in this testing situation actually results in race improvement. But, even if it is as useful as you allude how much impact has this usefulness had on cycling? For instance.

How many people who own a GM actually know it can be used for this purpose? My guess is less than 1%.

Of those who know of this use, how many do you think have done so? My guess, less than 10%. Certainly none of the Computrainer owners.

Of those who have done this test, how many do you think have done it in such a way that the number received is reliable and accurate? I would be surprised if it were as high as 50%.

Of those who have run the test, how many do you think have made multiple runs, changing position or equipment to optimize aerodynamics. My guess, not very many.

So, of those who own this amazing aerodynamic measuring device, what do you think the average aerodynamic improvement the average user has seen because of their ownership of this device? Not much I suspect.

Photovoltaic cells have the potential to eliminate the US need for imported oil but so far, they have had little impact along those lines. Computers can design life saving molecules for medicine but most people use them for email and personal entertainment (including hanging out in internet forums). I could say the same about my own product. What is one of the more common ways a GM owner use to improve their aerodynamics? I would submit they post a picture to the internet and ask others to critique their position. The fact that something can do something doesn't mean that it is regularly used to its potential.

So, if you have some evidence that the potential of this device to do all these wondrous things actually pans out in the real world with real world improvements of any significance to cycling please let us know what it is.

This potential doesn't seem like much of a justification for the average person to purchase a GM if the only real benefit of the device is something they will never do.

 

[FrankDay]

He's gonna need some pretty short cranks as his gut is going to affect how high he can bring his knees up

And, if he is going to get on my cranks, I better beef them up a bit.

 

[CoachFergie]

I am claiming benefits in aerodynamics using short cranks that come pretty much automatically, no need for any testing. That doesn't mean that the benefits couldn't be improved by serious testing.

"So Frank Day".

2. While I would admit that the chung technique is probably quite reliable and useful in giving an aerodynamic drag number similar to what can be achieved in a wind tunnel again it has never been "proven" that such precision actually in this testing situation actually results in race improvement. But, even if it is as useful as you allude how much impact has this usefulness had on cycling? For instance.

Again confusing measurement with outcomes. It's the changes in position that lead to changes in aerodynamics. The measure doesn't affect performance.

But you know that. I assume this is just another Snake Oil Tactic. Keep repeating the lie enough and peoples resistance will break. Keep trying

How many people who own a GM actually know it can be used for this purpose? My guess is less than 1%.

How does knowledge of a test invalidate the test itself?

Of those who have done this test, how many do you think have done it in such a way that the number received is reliable and accurate? I would be surprised if it were as high as 50%.

How does the skill level of the person in running the test invalidate the test itself?

Of those who have run the test, how many do you think have made multiple runs, changing position or equipment to optimize aerodynamics. My guess, not very many.

How does the ability of the person doing the test to carry out the optimal number of runs invalidate the test?

So, of those who own this amazing aerodynamic measuring device, what do you think the average aerodynamic improvement the average user has seen because of their ownership of this device? Not much I suspect.

None, a measurement device measures. End of story.

Photovoltaic cells have the potential to eliminate the US need for imported oil but so far, they have had little impact along those lines. Computers can design life saving molecules for medicine but most people use them for email and personal entertainment (including hanging out in internet forums). I could say the same about my own product. What is one of the more common ways a GM owner use to improve their aerodynamics? I would submit they post a picture to the internet and ask others to critique their position. The fact that something can do something doesn't mean that it is regularly used to its potential.

Cool story Bro!

The most common way is on an indoor track with no other riders and making changes while holding either speed or power constant. Not as precise as the wind tunnel but then in the wind tunnel even with the rider producing race level power it's not the same as riding on the track or road which is why we test in both situations.

In most cycling events the differences in performance are so close the level of precision in measurement is warranted. The don't measure the pursuit with an hourglass (unless I was racing).

So, if you have some evidence that the potential of this device to do all these wondrous things actually pans out in the real world with real world improvements of any significance to cycling please let us know what it is.

Still confuses measurement with experiments in training, diet, equipment and so forth.

This potential doesn't seem like much of a justification for the average person to purchase a GM if the only real benefit of the device is something they will never do.

I expect some people like to know if performance really has improved just in case a course is changed, shortened, weather changes or they want to know if that investment in time trying a new product is warranted.

If you are lucky you will find the research has even done that job for you. Like crank length, cleat position and Gimmickcranks.

 

[FrankDay]

You are imagining things, Frank. I re-read it again about half an hour ago - there was very little humour in it (unless you are referring to the dodgy re-workings of CoachFergie's username - and even then a bunch of *&^@#$ is hardly the paragon of wit)

I was looking at my PM's and looked again at the apology to me from Blutto. In it he mentions the "reworked" name of coach Fergie, which I am having a hard time finding particularly offensive. Perhaps there are some regional phrases of which I am not aware of worthy of pulling, but I find it hard this was one of them. I will not repeat it for fear of offending someone but if anyone is interested what might be found offensive by a moderator here send me a PM and you can draw your own conclusion.

But, every 4th or 5th post or so Fergie calls me a liar, which I find offensive, but, apparently, that doesn't bother you. While it is not a dodgy re-working of my screen name it does seem, if it is not true, this would put the web site at some legal risk if it is left up as being true.

 

[CoachFergie]

But, every 4th or 5th post or so Fergie calls me a liar, which I find offensive, but, apparently, that doesn't bother you.

Why am I not surprised that you find the truth offensive.

If it irks you so much you may want to reconsider misrepresenting the purpose of a power meter. That is a valid and reliable measure of cycling performance. Coaches and scientist's use them to test training methods, assess demands of events, test the physical ability of the rider, measure differences in position or changes in equipment.

So when someone claims...

1. Shorter cranks will improve power output for most.

And can't provide any evidence of this and then proceeds to undervalue the concept of measuring power in the first place leaves himself open for any ridicule they receive.

 

[CoachFergie]

While it is not a dodgy re-working of my screen name it does seem, if it is not true, this would put the web site at some legal risk if it is left up as being true.

You do know in court you would actually have to produce evidence for your claims

 

[Martin318is]

I was looking at my PM's and looked again at the apology to me from Blutto. In it he mentions the "reworked" name of coach Fergie, which I am having a hard time finding particularly offensive. Perhaps there are some regional phrases of which I am not aware of worthy of pulling, but I find it hard this was one of them. I will not repeat it for fear of offending someone but if anyone is interested what might be found offensive by a moderator here send me a PM and you can draw your own conclusion.

But, every 4th or 5th post or so Fergie calls me a liar, which I find offensive, but, apparently, that doesn't bother you. While it is not a dodgy re-working of my screen name it does seem, if it is not true, this would put the web site at some legal risk if it is left up as being true.

Frank - stop trying to use fallacious reasoning on me.

At no time did I state or even imply that the #$%&^ was the reason for deleting the post. The deletion was because it was effectively an off topic addition on the back of my warning to both yourself and Fergie.

I am unclear on why your PM inbox would contain the content of a post as opposed to a PM but either way that is immaterial.

You are right. See the PM I have just sent to yourself and CoachFergie.

 

[Martin318is]

Frank and Fergie - read the PM I just sent carefully before posting again in the public forum.

 

[FrankDay]

Back to being on topic hopefully.

One more data point for those who care. Drew's report today. He is now down to trying 90 mm cranks.

"I rode the 90s today to work and seemed real real good. Much more pulling up on the pedals - and more aero and maybe even more comfortable. I felt very good riding in today and kept the cadence around average of 87. Got up to 149 on the downhill and can still push at 68-70 cadence. Funny though how our mind has a computer for power and cadence and crank lenght. I gravated from an average cadence of 78 to 87 in one ride."

I will let it go at that although I think I can explain why for many of his observations (or so I have a theory that I think explains them). Let me know if you are interested.

 

[Alex Simmons/RST]

I am claiming benefits in aerodynamics using short cranks that come pretty much automatically, no need for any testing.

I don't accept that premise on face value.

Demonstrate the sustainable power to aero drag ratio has been improved and I'll believe you.

1. I mention the GM as an effort feedback device because that is how the vast majority of owners actually use the device.

It's still a strawman.

2. While I would admit that the chung technique is probably quite reliable and useful in giving an aerodynamic drag number similar to what can be achieved in a wind tunnel again it has never been "proven" that such precision actually in this testing situation actually results in race improvement. But, even if it is as useful as you allude how much impact has this usefulness had on cycling? For instance.

Well since I have performed such testing in race conditions when training and also used actual race data (e.g. for a client that set a world masters hour record), then I have my own evidence that this is in fact the case.

I even quantified precisely how much additional distance was attained from the improvements made (or would have been lost with poor choices).

How many people who own a GM actually know it can be used for this purpose? My guess is less than 1%.

Of those who know of this use, how many do you think have done so? My guess, less than 10%. Certainly none of the Computrainer owners.

Of those who have done this test, how many do you think have done it in such a way that the number received is reliable and accurate? I would be surprised if it were as high as 50%.

Of those who have run the test, how many do you think have made multiple runs, changing position or equipment to optimize aerodynamics. My guess, not very many.

So, of those who own this amazing aerodynamic measuring device, what do you think the average aerodynamic improvement the average user has seen because of their ownership of this device? Not much I suspect.

What an amazing strawman argument!
That is a classic.

"Many are not aware or not sure how to use a ruler to best advantage, so therefore the ruler is useless."

"Most don't know how to tune their car's engine, therefore tuning an engine is useless and doesn't result in performance improvement."

How about learning? Or getting help from someone that does know.

Photovoltaic cells have the potential to eliminate the US need for imported oil but so far, they have had little impact along those lines. Computers can design life saving molecules for medicine but most people use them for email and personal entertainment (including hanging out in internet forums). I could say the same about my own product. What is one of the more common ways a GM owner use to improve their aerodynamics? I would submit they post a picture to the internet and ask others to critique their position. The fact that something can do something doesn't mean that it is regularly used to its potential.

So, if you have some evidence that the potential of this device to do all these wondrous things actually pans out in the real world with real world improvements of any significance to cycling please let us know what it is.

This potential doesn't seem like much of a justification for the average person to purchase a GM if the only real benefit of the device is something they will never do.

There must be a special this month at Wal-Mart on Strawmen.

 

[FrankDay]

I don't accept that premise on face value.

Demonstrate the sustainable power to aero drag ratio has been improved and I'll believe you.

Nothing says you have to accept this on face value or anything else. It is a hypothesis that I believe will apply to most riders now, whenever it gets tested scientifically. Let me reiterate the basis for this thinking.

1. On the aero front, my thoughts on reducing drag simply follow well-known aerodynamic principles, if one doesn't raise the handlebars when shortening the cranks and raising the seat. That change invariably will reduce frontal area unless the front is so low that rasing the seat pushes the rear end up above the shoulders/head. Don't know anyone this low in front. If frontal area drops we would expect aero drag to drop. We just don't know how much.

2. Regarding power. Well everyone is going to be different here but Martin demonstrated that max power doesn't drop until the rider get below 145. And, my own experience and the reports I have received from others who have experimented with this confirm that power usually increases or, at least, doesn't drop when crank length is shortened from where they are now.

None of this has been proven so it is reasonable to be skeptical. But, I have seen enough to convince me that my theory is probably correct, at least for most people. Therefore, I encourage people to experiment with this themselves to see what happens to them.

 

[oldborn]

Hey, hey wait a minute.
I found it very important to clarify things about insults and calling names here.
Long time ago I called Fargo: fat mediocracy, no name coach, realized that I cross the line.
I apologized to him twice PM. Never reply, so I think that guy who do not accept apologize is not very nice one.
On the other hand that same guy calling people liar, idiots, fools without even realizing that might hurt someone.
Putting Frank at even with Fargo is just unfair. When things get out control it is hard to be cool, but I did not saw Frank calling him names, did someone?

So I just call that guy Fargo, makes jokes about him, but never call him idiot, and apologize once again

So the question here is: Who is the guy here who really insults people?
IMHO, coach Fargo (even here he would be out of coach license) all the time.
I just do not care, but will never gave a kid coaching by sucha angry man, who do not accept apologize.

P.S. Not even in my wildest dreams, I did not tell someone how he should do mod job or criticise him Sorry to hijack thread once again

 

[CoachFergie]

Nothing says you have to accept this on face value or anything else. It is a hypothesis that I believe will apply to most riders now, whenever it gets tested scientifically. Let me reiterate the basis for this thinking.

What Alex is suggesting is that the hypothesis is easily tested with a power meter. One could attain more accurate data in the wind tunnel or on an indoor velodrome. Peter Sagan was tested like this in the early season using both track and tunnel.

1. On the aero front, my thoughts on reducing drag simply follow well-known aerodynamic principles, if one doesn't raise the handlebars when shortening the cranks and raising the seat. That change invariably will reduce frontal area unless the front is so low that rasing the seat pushes the rear end up above the shoulders/head. Don't know anyone this low in front. If frontal area drops we would expect aero drag to drop. We just don't know how much.

We would expect a rider to be in the most aerodynamic position possible. Without tunnel or power meter data the eye-crometer test from Worlds TT seemed to indicate that most riders were in optimal position for aerodynamics.

Having done a considerable number of bike set ups in competitive, recreational and clinical (in conjunction with a physio or doctor) I have found the aero position the easy part.

2. Regarding power. Well everyone is going to be different here but Martin demonstrated that max power doesn't drop until the rider get below 145. And, my own experience and the reports I have received from others who have experimented with this confirm that power usually increases or, at least, doesn't drop when crank length is shortened from where they are now.

Those observations would run counter to what the research has shown. A distinction in reporting any changes would have to be made between performance and result differences.

None of this has been proven so it is reasonable to be skeptical. But, I have seen enough to convince me that my theory is probably correct, at least for most people. Therefore, I encourage people to experiment with this themselves to see what happens to them.

Martin in his presentation suggested that the most either a very short or a very tall rider would lose in power was .5% if they rode 170mm cranks. For the average height cyclist this possible change would be far lower.

As a coach and post graduate sport science student I would suggest that of the many experimental decisions one must make during a cyclist's career that less than a 1% improvement in performance is not worth pursuing.

 

[Alex Simmons/RST]

1. On the aero front, my thoughts on reducing drag simply follow well-known aerodynamic principles, if one doesn't raise the handlebars when shortening the cranks and raising the seat. That change invariably will reduce frontal area unless the front is so low that rasing the seat pushes the rear end up above the shoulders/head.

Hmmm, I have data showing a rider's aero drag increased with seat height, with no change to bars.

I can't specifically say with respect to FA, as it's CdA (and power) that matter.

So, no, I don't consider that to be a well-known aerodynamic principle, or if it is, it's isn't generally applicable.

 

[Martin318is]

Hey, hey wait a minute.
I found it very important to clarify things about insults and calling names here.

its not just about insults in this case.
A statement has been made and a line drawn. Everyone knows how it applies to themselves so nothing else needs to be said.

 

[Night Rider]

… can you explain the Sammy Sanchez and Cadel Evans endorsements on your site. Are they endorsements? Do they know they are there?

Not to beat a dead horse but just got a call from a customer in Australia. Anyhow, in the back and forth he mentioned that in the latest issue of RIDE magazine they had an article on Cadel and had a picture of him with his training bike with the you-know-whats on them, even gave them a mention in the article. Not, of course, that it proves anything scientifically.

Those of you with access to the magazine might want to check it out.

I saw your post earlier in the week but was too busy working and training to get the magazine back out and check. Just done it now and couldn't find any mention or any picture. Quote a page number and I will have a look again if you want.

 

[FrankDay]

Hmmm, I have data showing a rider's aero drag increased with seat height, with no change to bars.

I can't specifically say with respect to FA, as it's CdA (and power) that matter.

So, no, I don't consider that to be a well-known aerodynamic principle, or if it is, it's isn't generally applicable.

AFAIK, there are two "well known" aerodynamic principles at play here. frontal area and shape. Fairings increase frontal area but make up for it by such a good shape that overall drag is decreased. But, if shape remains essentially the same, reducing frontal area should reduce drag. So, I guess it is possible that one can reduce frontal area and increase drag, but that would not be expected if the only change is raising the seat since one wouldn't expect a dramatic change in shape.

That having been said, most of the riders I know who have made this change report being able to lower their handlebars from what they previously thought was the best they could do. Therefore, I would expect an even larger lowering of the frontal area to those who push the limits.

 

[FrankDay]

I saw your post earlier in the week but was too busy working and training to get the magazine back out and check. Just done it now and couldn't find any mention or any picture. Quote a page number and I will have a look again if you want.

I wasn't given a page number. Simply that he saw the article in the magazine. Maybe it was an old issue that he thought new because he commented the picture had Cadel in his Lotto kit.