The importance of crank length to the cyclist.

[Oldman]

All I had to do to lower my position in front was follow John Cobb's advice to tilt the saddle "up" at the front and also have a greater hip angle, flatter back and dropped my bars by 4cm! Free speed!!!

I did the same with the double-jointed Felt DA stem, usually part of their track bike. Simply rolled my entire position into that shape and adjusted the saddle. Made about a 2 minute difference on a known 40km course. I'm 5'7" and used 172.5 cranks because I have good strength/range of motion. I use 170's for road because the 172.5 length isn't as responsive to change of pace; particularly on climbs. 167.5 for the track and have tried smaller but sacrifice power for cadence and we have a large open track.

 

[CoachFergie]

I did the same with the double-jointed Felt DA stem, usually part of their track bike. Simply rolled my entire position into that shape and adjusted the saddle. Made about a 2 minute difference on a known 40km course. I'm 5'7" and used 172.5 cranks because I have good strength/range of motion. I use 170's for road because the 172.5 length isn't as responsive to change of pace; particularly on climbs. 167.5 for the track and have tried smaller but sacrifice power for cadence and we have a large open track.

5' 8" and for my leg length some of the calculations suggest 172.5 but they never worked for me. I run 165s on my track bike and when I could use that for road time trials was always 60-90s faster for 16km than clip on bars on the road bike at the same power. I would put most of that speed to using a fixed gear and a lower position on the track bike using pursuit bars.

Will be in the wind tunnel on Monday with a track cyclist who is taller and is not the most aero person on a bike. Might try my 165s if possible as he currently uses 172.5mm cranks. He is 1.86m tall but I have another well performed trackie who is 1.75m running 172.5 on the track. Two Bronze at Junior Worlds as a first year and his position is very low with no compromise in achieve a low frontal area. I'm pretty ****ed. A Bronze in Omnium winning the Kilo round in 1:04.0 which would have got him Silver in Kilo event and I'm picking had he ridden the Kilo would have gone faster.

 

[Captain Serious]

^ It's all your fault..... I just bought some cheap 165s on Ebay for $46 (8sp 105s). It'll be interesting to see how they go. I haven't used 165s since I bought my first track bike about 20 years ago

 

[FrankDay]

^ It's all your fault..... I just bought some cheap 165s on Ebay for $46 (8sp 105s). It'll be interesting to see how they go. I haven't used 165s since I bought my first track bike about 20 years ago

Baby steps. But, at least they are steps. (Remember: the longest journey starts with a single step!) Let us know your experience.

 

[Captain Serious]

Baby steps. But, at least they are steps. (Remember: the longest journey starts with a single step!) Let us know your experience.

Ha! Yep, baby steps. I've done a few rides with the 265s, but I can't give ya much more that the obvious, which is:

Going from 172.5s, I immediately (naturally) noticed the smaller pedalling circle, and also noticed how whoppingly high I felt over the pedals through the top of the stroke, which was compounded by me rasing the saddle roughly 7mm to compensate for the shorter reach through at the bottom of the stroke. I reckon I'm able to get my upper body way lower while still pedalling hard, which I gather makes me more aero.

I expected to feel less off-the-saddle leverage, but didn't. When off the saddle, I had a weird feeling that the pedals were "falling away faster underneath me", which I know might sound strange.

I said the following on other forums a few years ago when I went back to 172.5 from a year on 180s, and, interestingly, I read yesterday someone saying virtually the opposite: To me, using shorter cranks feels more like a bodyweight stomp -- kinda like stomping aluminium cans -- somewhat 'sparing' my quads, where longer cranks feels like doing deep leg presses, using more quads. It's almost as if the weight of my legs is helping to push the shorter cranks, slightly relieving the muscles. Hmmm, reading this back, it sounds a bit goofy. I'd say it's logical that the increased knee and hip flexion with longer cranks makes it feel like I'm using more quad.
And this was probably my imagination -- but it may support this dodgy theory of mine -- but it seemed as though my HR was a few beats lower for the same speed on shorter cranks, 'irregardless' of possibly being more aero

 

[FrankDay]

I said the following on other forums a few years ago when I went back to 172.5 from a year on 180s, and, interestingly, I read yesterday someone saying virtually the opposite: To me, using shorter cranks feels more like a bodyweight stomp -- kinda like stomping aluminium cans -- somewhat 'sparing' my quads, where longer cranks feels like doing deep leg presses, using more quads. It's almost as if the weight of my legs is helping to push the shorter cranks, slightly relieving the muscles. Hmmm, reading this back, it sounds a bit goofy. I'd say it's logical that the increased knee and hip flexion with longer cranks makes it feel like I'm using more quad.
And this was probably my imagination -- but it may support this dodgy theory of mine -- but it seemed as though my HR was a few beats lower for the same speed on shorter cranks, 'irregardless' of possibly being more aero

With longer cranks you are forced to "use your quads more", at least for each revolution. While that sounds like it should be a positive, if the increased ROM required of the knee joint takes it out of a good efficiency range then you can lose a lot of efficiency, making the HR go higher for the same effort.

Here is my expectation of what one might find. The "5 hour" effort line comes from actual data obtained by someone else. The other lines are what I predict will be found when higher powers are tested.

 

[CoachFergie]

With longer cranks you are forced to "use your quads more", at least for each revolution. While that sounds like it should be a positive, if the increased ROM required of the knee joint takes it out of a good efficiency range then you can lose a lot of efficiency, making the HR go higher for the same effort.

Here is my expectation of what one might find. The "5 hour" effort line comes from actual data obtained by someone else. The other lines are what I predict will be found when higher powers are tested.

Made up charts. "So Frank Day"!

HR isn't efficiency Frank, you're a Doctor and know better. Keep lowering that bar!

 

[FrankDay]

HR isn't efficiency Frank, you're a Doctor and know better. Keep lowering that bar!

Putting on my MD/anesthesiologist hat now Fergie. All other things being equal in any one individual HR generally follows oxygen consumption. In the chart, an attempt was made to hold everything constant except crank length and see the effect on HR. If HR goes down for the same power then it is a reasonable inference that oxygen consumption has also gone down, which would mean, generally, that efficiency has gone up. We cannot say what the numbers actually are but it is reasonable to infer efficiency has improved if power remains constant and HR drops.

You seem to be the only person I know who doesn't seem to give a hoot as to what the HR is as long as the power goals are being met.

Anyhow, based upon the preliminary data of others, the data of Martin, my experience, and my own thought experiments I have predicted how I think optimum crank length will change with power. So, in that sense, the chart is "made up". Others might call it a hypothesis. Anyhow, when you get some actual data that proves me wrong let me know. Until then, allow me my musings.

 

[CoachFergie]

"What I think happens".

"So Frank Day!"

Let us know when you have real data.

 

[FrankDay]

"So Frank Day!"

Let us know when you have real data.

Well, the Martin data and the blue line data are "real data" on that graph. So, I am letting you know.

If you have a hypothesis as to how crank length affects power/efficiency why don't you join the conversation and let everyone know what it is (and why you might think that). Otherwise, all you do is come across as a curmudgeon, only willing to criticize, never offering anything positive.

 

[CoachFergie]

Well, the Martin data and the blue line data are "real data" on that graph. So, I am letting you know.

If you have a hypothesis as to how crank length affects power/efficiency why don't you join the conversation and let everyone know what it is (and why you might think that). Otherwise, all you do is come across as a curmudgeon, only willing to criticize, never offering anything positive.

Martin found no significant changes. No increased power or metabolic efficiency from changes in crank length. Martin's suggestion was this allows you to experiment with crank length to improve aerodynamics. For him this was a change to 165mm cranks on his time trial bike. But having come from sprint cycling where they use ~165mm cranks I would expect this wasn't a huge shift. But there are other options to improve aerodynamics than playing round with crank length.

But I assume that doesn't contribute to the science (fiction) of selling Gimmickcranks.

 

[FrankDay]

Martin found no significant changes. No increased power or metabolic efficiency from changes in crank length. Martin's suggestion was this allows you to experiment with crank length to improve aerodynamics. For him this was a change to 165mm cranks on his time trial bike. But having come from sprint cycling where they use ~165mm cranks I would expect this wasn't a huge shift. But there are other options to improve aerodynamics than playing round with crank length.

While the differences were not statistically significant Martin's highest measured power occurred at 145 mm crank length, not 170. Even if there is not difference in power I would like to you to make an argument that it is best for the rider to use 170 if they are also taking aerodynamic benefits into account.

Why on earth would Martin take his own data and decide to change to 165 vs 145 other than, perhaps, he was wedded to a manufacturer and that manufacturer didn't make a crank shorter than 165 (the big three)? It is non-sensical thinking, IMHO, letting what is readily available determine what is best for you (edit: especially in view of the fact that there is zero evidence that the choice of crank manufacturer or BB type makes any difference regarding power output). Might work for the average guy but not for anyone who claims to be half serious.

 

[CoachFergie]

The key thing is the differences are non significant. That is where the serious coach or researcher moves on to other areas in the performance jigsaw like training, recovery, diet, motivation etc. I guess because you are only here to sell Gimmickcranks you continue to labour the point.

"So Frank Day"

 

[Shady87]

One of the big problems with getting statistically significant results is the number of participants required.
While Martin found no significant changes, this is because he is using the language of a researcher, where 'significant' has precise implications.
What dis data shows is that further research is justified.
I hate to agree with FrankDay, because he really does come across as a salesman, but I think he may be on to something.
He is releasing a product to market before its full practical applications have been discovered.

 

[oldborn]

Fargo, who s that young lad on avatar?
Carry on

 

[CoachFergie]

One of the big problems with getting statistically significant results is the number of participants required.
While Martin found no significant changes, this is because he is using the language of a researcher, where 'significant' has precise implications.
What dis data shows is that further research is justified.
I hate to agree with FrankDay, because he really does come across as a salesman, but I think he may be on to something.
He is releasing a product to market before its full practical applications have been discovered.

Martin and others have carried out further research and the results were pretty much the same. It's not an area of practical significance. It doesn't cost you power so if there is the potential for improved aerodynamics a shorter crank isn't going to hinder performance.

Gimmickcranks are a solution in search of a problem!

Frank has encountered a similar lack of practical significance with his pedalling technique angle.

 

[FrankDay]

One of the big problems with getting statistically significant results is the number of participants required.
While Martin found no significant changes, this is because he is using the language of a researcher, where 'significant' has precise implications.
What dis data shows is that further research is justified.
I hate to agree with FrankDay, because he really does come across as a salesman, but I think he may be on to something.
He is releasing a product to market before its full practical applications have been discovered.

Fergie doesn't quite understand some of the nuances of this research stuff, of what it takes to reach statistical significance, of the restrictions put on the author on what can be said or not said in scientific journals, or how those involved in the real world might read a little more into the data than what the journal editors allowed the author to say.

I guess I am trying to "sell" the concept but it doesn't take buying my product for someone to experiment with this for themselves. Short cranks are readily available on the internet for very reasonable prices. I just happen to think that it is such a big deal that I have also incorporated the possibility to those early adopters who also want to train the PowerCranks pedaling technique. It does seem it might be possible that there might be a synergy to the two ideas that make the combination of PowerCranks with short cranks even more powerful than each alone - but that is pure conjecture.

 

[FrankDay]

Martin and others have carried out further research and the results were pretty much the same.

Perhaps you could point us to this work? Really, if it has been done, let's add it to the discussion.

 

[CoachFergie]

I just happen to think that it is such a big deal that I have also incorporated the possibility to those early adopters who also want to train the PowerCranks pedaling technique.

11 years and do data supporting either concept.

"Big deal"

"So Frank Day"

 

[CoachFergie]

Perhaps you could point us to this work? Really, if it has been done, let's add it to the discussion.

I assume if you know how to spam the internet you know how to do a Google search. Jim has commented on the research on Slowtwitch in a thread you were part of before being kicked off the forum. He has also put a presentation on the subject online and this link is part of this thread. You know where he and other academics sit on the subjects.

Playing dumb?

"So Frank Day"

 

[oldborn]

Fargo i really can not see reason why so obsessed with Frank/cranks.
Let me think, he stole your prome Queen years ago, he is now living in your ex wife house after nasty divorce (which is similar with first situation), Frank played main role in high school play and you were stunt etc.

Nevertheless it is not healthy situation for you, and it is really boring

 

[Boeing]

Fargo i really can not see reason why so obsessed with Frank/cranks.
Let me think, he stole your prome Queen years ago, he is now living in your ex wife house after nasty divorce (which is similar with first situation), Frank played main role in high school play and you were stunt etc.

Nevertheless it is not healthy situation for you, and it is really boring

hey oldbornidentity, you ever been to Fargo? It is boring!

hahahah

 

[FrankDay]

Jim has commented on the research on Slowtwitch in a thread you were part of before being kicked off the forum. He has also put a presentation on the subject online and this link is part of this thread. You know where he and other academics sit on the subjects.

Yes, I am aware of all of that and I am not aware of anything in what you mentioned that goes beyond what has been already said. If I missed something I am sure you could point it out. What I asked was for you to point to specific work done by Martin or anyone else that goes to this specific discussion topic.

Further, you and I aren't the only people reading this thread (although if you keep up your rants perhaps that might become the case - your hope I am sure) such that if you allude to something it should be your duty to point out to those others if you want your point to be clear or understood. Incorporating personal attacks as the major part of your argument only makes your argument on the topic look weak and you look petty.

BTW, it is not clear that this thread is having any affect on PowerCranks sales, despite what you might think. Despite offering these cranks that allow for very short testing, so far only about 10% of our sales, since we came out with these ultra-adjustable cranks, are of the ultra-adjustable variety (and many of those have come after much arm-twisting when I am talking with the customer on the phone). Most of our sales continue to be to those who simply are looking for PowerCranks functionality. I doubt there will be much change until someone wins a major race using radically shorter cranks.

 

[oldborn]

hey oldbornidentity, you ever been to Fargo? It is boring!

hahahah

Is it real place? Although i like movie
Hope it will becomes more interesting without Fargo jumping at every post Frank made

 

[FrankDay]

Hope it will becomes more interesting without Fargo jumping at every post Frank made

I have been thinking of starting a thread to explore whether skittles or gummie bears (or snickers vs milky way) make a better long ride energy source and see if Fergie would jump in and accuse me of starting it just to sell PowerCranks. (you may not be familiar with these but they are American candies)