The importance of crank length to the cyclist.

[FrankDay]

Sorry Frank but did you say that Drew previously rode 182.5mm cranks?

Just wondering if he has ever tried the event on normal length cranks.

All I know is he did it the year before on 182.5. I will try to find out. Edit: Also, that year was his best year but it was also the first year he race on his PowerCranks.

 

[Martin318is]

The conversation would get really interesting next year if he were to try going back to a completely standard length, standard crank and got a time in between the two he has already done.

Imagine the intriguing conversation if we had 3 data points in a clear linear progression on crank length but NOT on date! In other words, it would appear that the times get better the shorter the crank, and there would be a query on the training improvement component because he would be slower than he was this year.

It'd be even better if his times - after being normalised for distance - were a perfect linear relationship.

I'm not actually kidding, THAT would be a fun conversation!
(any chance you can convince him to try it next year "for science", Frank?)

 

[acoggan]

Seeing aerodynamics is a claimed benefit of running shorter cranks how do people propose these measures are validly and reliably measured?

Just an FYI: I used a powermeter to determine that, at least for me, lowering my saddle by 10 cm (equivalent to going from a 170 mm to a 70 mm crank, if leg flexion is held constant) did not lower my CdA enough to compensate for the reduction in performance ability.

 

[Oldman]

All I know is he did it the year before on 182.5. I will try to find out. Edit: Also, that year was his best year but it was also the first year he race on his PowerCranks.

I talked a tall teammate down from 180 cranks and he did have his best TT ever...on 175s. He started road racing on 172.5s and they were too small for his cadence so he went up. He won alot of races including a boatload of National Championships. His position was never an issue, by the way.

 

[Captain Serious]

Another 'short crank' anecdote: I really hurt my neck trying to get my upper body very low and lifting my head up to see where I was going. Do'h! Beware! It's slowly improving. Then, I had the worst toothache in me life, which I suspect was related, and the dentist kinda confirmed that it's possible, but I think he was humouring me

 

[FrankDay]

Just an FYI: I used a powermeter to determine that, at least for me, lowering my saddle by 10 cm (equivalent to going from a 170 mm to a 70 mm crank, if leg flexion is held constant) did not lower my CdA enough to compensate for the reduction in performance ability.

Could you please explain why you believe that:
1. lowering your seat any amount would improve your aerodynamics
2. lowering your seat 10 cm is the "equivalent" of shortening your cranks 10 cm from a power generation perspective.

 

[FrankDay]

The conversation would get really interesting next year if he were to try going back to a completely standard length, standard crank and got a time in between the two he has already done.

Imagine the intriguing conversation if we had 3 data points in a clear linear progression on crank length but NOT on date! In other words, it would appear that the times get better the shorter the crank, and there would be a query on the training improvement component because he would be slower than he was this year.

It'd be even better if his times - after being normalised for distance - were a perfect linear relationship.

I'm not actually kidding, THAT would be a fun conversation!
(any chance you can convince him to try it next year "for science", Frank?)

Your suggestion is not science or, at least, very good science. One rider giving three data points each a year apart would be interesting but not much more.

My guess is this rider, as most of us do, is going to continue to do what he thinks is best for him and he doesn't really care what any of you people think. From the perspective of this thread I can only transmit what he does and what he says.

There is another test coming soon. He will be doing Furnace Creek 508 in two weeks. I understand he is now experimenting with 90 mm cranks and I have suggested to him that he might consider something like 90 mm cranks on the flats (for the aero benefits) and 110 mm cranks when climbing (so he can stay with his current gearing) for that event. Unfortunately, he has not done this event before so we will have nothing to compare except his performance compared to the other athletes in this race.

 

[CoachFergie]

Just an FYI: I used a powermeter to determine that, at least for me, lowering my saddle by 10 cm (equivalent to going from a 170 mm to a 70 mm crank, if leg flexion is held constant) did not lower my CdA enough to compensate for the reduction in performance ability.

Yes going back over 503 posts of no evidence for the "importance" of crank length I have mentioned using either a power meter or wind tunnel to get the some data.

 

[Martin318is]

Your suggestion is not science or, at least, very good science. One rider giving three data points each a year apart would be interesting but not much more.

If you couldn't spot that that post was dripping with sarcasm (whilst also generally similar to some of your earlier posts) then there isn't much left to be said.

To reference Dougas Adams, I guess you are going to say something like, "I dunno, I guess our minds are just too highly trained."

 

[daveinzambia]

If you couldn't spot that that post was dripping with sarcasm (whilst also generally similar to some of your earlier posts) then there isn't much left to be said.

To reference Dougas Adams, I guess you are going to say something like, "I dunno, I guess our minds are just too highly trained."

it gives me a headache just trying to think down to your level

 

[FrankDay]

If you couldn't spot that that post was dripping with sarcasm (whilst also generally similar to some of your earlier posts) then there isn't much left to be said.

I get confused too easily. I really don't understand what you are thinking on this issue and what is sarcasm or not. You are a moderator but also a participant. In the relevant post you said you were "not kidding" so I presumed you were serious.

Regarding being confused as to where you stand or what you believe I presume it was you who pulled what I thought was Blutto's insightful commentary on the quality of some of the observations posted here by one particular participant which makes me wonder exactly where you stand or what you were trying to protect. That wondering perhaps lowered my "sarcasm" warning system for that post.

Sometimes these discussions that I think should be for the exchanging of ideas on theoretical and unproven topics get a little (lot) mean. This seems to be particularly true if I become involved so I tend to be a little defensive. Sorry about that in this instance.

 

[FrankDay]

… 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.

 

[acoggan]

Yes going back over 503 posts of no evidence for the "importance" of crank length I have mentioned using either a power meter or wind tunnel to get the some data.

Right-o, I was just chiming in to reinforce your point.

 

[acoggan]

Could you please explain why you believe that:
1. lowering your seat any amount would improve your aerodynamics
2. lowering your seat 10 cm is the "equivalent" of shortening your cranks 10 cm from a power generation perspective.

1. At least theoretically, lowering your saddle can reduce drag by reducing total frontal area.

2. It's not, but my anecdote does demonstrate that A) the hypothesis in #1 above was correct, but the effect wasn't large enough to be worth pursuing, and B) that you can use a powermeter to measure such things.

BTW, I've also tested crank lengths as short as 145 mm, but am back on 170 mm for all of my riding. I'll leave it up to you to deduce why that is.

 

[Stingray34]

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.

got a page number? from memory, I don't think there's a pic, but a mention from the text of Rob Arnold's book, Close To Farking, about some type of crank on his training bike.

 

[FrankDay]

Right-o, I was just chiming in to reinforce your point.

How does an almost nonsensical post about using a GM to test the affects of crank length on aerodynamics by simulating such a change by lowering seat height have anything to do with either this thread or science?

You have yet to answer my question as to why you would think changing seat height would simulate changing crank length in either aerodynamics or power generation.

 

[FrankDay]

got a page number? from memory, I don't think there's a pic, but a mention from the text of Rob Arnold's book, Close To Farking, about some type of crank on his training bike.

I was told it was in a recent issue of Ride magazine. Picture was when he was on Lotto, I was told.

The Book reference is completely different without a picture.

 

[FrankDay]

1. At least theoretically, lowering your saddle can reduce drag by reducing total frontal area.

How? Moving saddle does nothing to head/shoulders or feet. All moving saddle down does is move pelvis/thighs out of the wind shadow of the chest/shoulders, increasing frontal area, IMHO? But, I am sure you can straighten me out on this as to how simply lowering the saddle lowers overall frontal area.

2. It's not, but my anecdote does demonstrate that A) the hypothesis in #1 above was correct, but the effect wasn't large enough to be worth pursuing, and B) that you can use a powermeter to measure such things.

Everyone knows you can use a GM to measure such things. The question is, does such measurement result in better racing than trying to do the same thing using alternative and cheaper methods?

BTW, I've also tested crank lengths as short as 145 mm, but am back on 170 mm for all of my riding. I'll leave it up to you to deduce why that is.

Cool. But, I would be more interested in seeing your testing data and protocol that led you to this decision. Would be much more useful for the purposes of this discussion.

 

[acoggan]

How does an almost nonsensical post about using a GM to test the affects of crank length on aerodynamics by simulating such a change by lowering seat height have anything to do with either this thread or science?

Isn't the discussion really about the interaction between joint angles, power output, and aerodynamic drag? Altering crank length is but one way of exploring this envelope; dramatically changing saddle height is another. My main point, though, is that not only does a powermeter let you test such things, some people HAVE tested such things (rather than just pontificating about them on a web forum).

You have yet to answer my question as to why you would think changing seat height would simulate changing crank length in either aerodynamics or power generation.

Apparently you missed my #2 above.

 

[acoggan]

How? Moving saddle does nothing to head/shoulders or feet. All moving saddle down does is move pelvis/thighs out of the wind shadow of the chest/shoulders, increasing frontal area, IMHO? But, I am sure you can straighten me out on this as to how simply lowering the saddle lowers overall frontal area.

I doubt it, but I'll try.

The "low sit" position entails not only dramatically lowering the saddle height, but the height of the aero bars as well (thus keeping the relationship between the heights of the shoulders and the hips the same). The results is a reduction in frontal area, and hence CdA.

Everyone knows you can use a GM to measure such things. The question is, does such measurement result in better racing than trying to do the same thing using alternative and cheaper methods?

There are no such alternatives. The closest you could come would be doing TT-style efforts on an indoor track, but even there environmental conditions often vary too much to allow you to reliable detect differences of the magnitude of interest here.

Cool. But, I would be more interested in seeing your testing data and protocol that led you to this decision. Would be much more useful for the purposes of this discussion.

I'm not sure there's much more to say. I've described the approach I use to determine CdA using a powermeter on many occasions/in many places (e.g., http://www.trainingandracingwithapowermeter.com/2010/04/which-is-faster-cervelo-p2t-or-javelin.html). To determine the impact on my sustainable power, I did a series of 20 min all out efforts, varying the crank length using a Latin Square design.

 

[FrankDay]

I doubt it, but I'll try.

The "low sit" position entails not only dramatically lowering the saddle height, but the height of the aero bars as well (thus keeping the relationship between the heights of the shoulders and the hips the same). The results is a reduction in frontal area, and hence CdA.

That is pretty easy to understand. The easiest way to reduce the frontal area is to lower the handlebars. You just happened to also lower the seat. It seems a bit "confusing" to describe this as lowering the seat to lower the frontal area since the two do not need to be adjusted together.

There are no such alternatives. The closest you could come would be doing TT-style efforts on an indoor track, but even there environmental conditions often vary too much to allow you to reliable detect differences of the magnitude of interest here.

Of course there are alternatives. Now you won't be able to get a number like you can using the PM but you certainly can determine relativity. Most people really don't care what the number is, all they want to know is what is fastest for them

I'm not sure there's much more to say. I've described the approach I use to determine CdA using a powermeter on many occasions/in many places (e.g., http://www.trainingandracingwithapowermeter.com/2010/04/which-is-faster-cervelo-p2t-or-javelin.html). To determine the impact on my sustainable power, I did a series of 20 min all out efforts, varying the crank length using a Latin Square design.

But, you didn't describe your training efforts on the different set-ups before testing. And, you didn't give us your actual data only asking us to surmise what the result was.

I would be interested in knowing exactly how you tested on the 145 cranks. Did you spend any time getting used to the crank length before testing? If so, how much? Did you change your bike fit beyond raising your seat and if you raised your seat did you also raise your handlebars? It is those kinds of details that make a difference to me so I can reach my own conclusion as to how valid your test was.

 

[FrankDay]

Isn't the discussion really about the interaction between joint angles, power output, and aerodynamic drag? Altering crank length is but one way of exploring this envelope; dramatically changing saddle height is another. My main point, though, is that not only does a powermeter let you test such things, some people HAVE tested such things (rather than just pontificating about them on a web forum).

You mean, like Martin? Anyhow, this thread is about what shorter cranks do or do not do. Yes, it involves joint angles. But, lowering seat height changes those joint angles, IMHO, in exactly the opposite direction, and you didn't mention this as your reason for posting but, rather, implied it was a good substitute for actually experimenting with crank length.

It was obfuscation to the nth degree. Looking professorial and saying nothing useful.

Apparently you missed my #2 above.

You had not posted yet when I was writing. We crossed in the interspace somewhere.

 

[oldborn]

How about this alternative for measuring drag coefficients (Coastdown test), without PM http://www.hadland.me.uk/coastdown.pdf.

I am not saying that we should go back to stone age, but there is alternative.
It may be complicated but lot cheaper than 2000$ PM I am just saying.
How coaches lived before PM?

 

[FrankDay]

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.

Not trying to beat a dead horse but I was relating this to a colleague and he told me he recently was contacted by a fairly big name young star who said this: "Cadel says I need to get on these ASAP". Too bad Cadel doesn't know anything about riding bicycles so it really means nothing about the usefulness of the product because it is neither proof nor science and everyone knows pedaling technique doesn't matter. Just push harder baby!!!

 

[CoachFergie]

Not trying to beat a dead horse but I was relating this to a colleague and he told me he recently was contacted by a fairly big name young star who said this: "Cadel says I need to get on these ASAP". Too bad Cadel doesn't know anything about riding bicycles so it really means nothing about the usefulness of the product because it is neither proof nor science and everyone knows pedaling technique doesn't matter. Just push harder baby!!!

Correct Frank, it does mean nothing.