The importance of crank length to the cyclist.

[42x16ss]

Noel has been spouting his opinion for the last several years. Based on what he observes from the video footage of Jacques Anquetil. Never supplied any data. Force measuring pedals have been available for decades and any data that a change in force application around the pedal stroke being of any benefit has yet to be found.

Bit like the claimed importance of crank length.

Asker Juekendrup wrote a paper on where to spend your money to really maximise your performance.

http://www.cyclesportcoaching.com/Files/HowToSpendMoney.pdf

But, but, but we're talking about 9-12 WEEKS here

Who wants to wait that long! And all that training is REALLY HARD!!!

Why do all that when I could just throw money at the problem

 

[CoachFergie]

You can buy a lighter or more aero frame NOW! Isn't life good!!!

 

[coapman]

Noel has been spouting his opinion for the last several years. Based on what he observes from the video footage of Jacques Anquetil. Never supplied any data. Force measuring pedals have been available for decades and any data that a change in force application around the pedal stroke being of any benefit has yet to be found.

Bit like the claimed importance of crank length.

Asker Juekendrup wrote a paper on where to spend your money to really maximise your performance.

http://www.cyclesportcoaching.com/Files/HowToSpendMoney.pdf

You learn absolutely nothing as to how forces are being applied by looking at another rider's pedaling, you have to discover it for yourself and then you can compare the action and basic set up. How could any benefit be found when a new technique was not being researched, all you had was repetitive comparison between variations of the same basic natural technique where there always was a dead spot sector between 11 and 1 o'c.

 

[CoachFergie]

You learn absolutely nothing as to how forces are being applied by looking at another rider's pedaling

Which is why we use force measuring pedals and we use a large enough sample of subjects to draw meaningful conclusions from the data.

you have to discover it for yourself and then you can compare the action and basic set up.

So every rider has to start the entire cycling process from scratch. Your comments sets the entire field of cycling science back a good 110 years.

How could any benefit be found when a new technique was not being researched, all you had was repetitive comparison between variations of the same basic natural technique where there always was a dead spot sector between 11 and 1 o'c.

Have you actually read all the research on pedalling technique? The testing of independent crank systems, rotor cranks, crank length and many other manipulations of the way we pedal and none have produced a better way of delivering power to the pedal than the natural method.

Two year old's I have taught to ride a bike have a better instinct for pedalling than you do! And (to keep things on topic) they have the disadvantage of excessively long cranks relative to their leg lengths.

 

[coapman]

but the rider's hands are holding the extensions. There is plenty of opportunity to prodive resistance through that hand position so I dont really see how this causes a loss of the ideal TT position..

We are talking here about maximal forward torque and resistance. This needs an imaginary direct resistance line between hand and shoulder which is parallel to the line in which the tangential force is being directed at the pedal at all times between 11 and 2 o'c. This is impossible with the arm in a fixed position on a rest. The arm and leg on each side are working independently and the whole body is involved in the action. You are applying your force between 11 and 5 o'c in exactly the same way as a (180 deg.) hand crank rider does it, but you have the added benefit of something for your hand to grasp to increase resistance and the resultant crank torque.

 

[CoachFergie]

We are talking here about maximal forward torque and resistance. This needs an imaginary direct resistance line between hand and shoulder which is parallel to the line in which the tangential force is being directed at the pedal at all times between 11 and 2 o'c. This is impossible with the arm in a fixed position on a rest. The arm and leg on each side are working independently and the whole body is involved in the action. You are applying your force between 11 and 5 o'c in exactly the same way as a (180 deg.) hand crank rider does it, but you have the added benefit of something for your hand to grasp to increase resistance and the resultant crank torque.

Yes we know the Scott Rake handlebar is the ideal bar to achieve this. And when were they banned by the UCI?

Keep dreaming.

 

[coapman]

Yes we know the Scott Rake handlebar is the ideal bar to achieve this. And when were they banned by the UCI?

Keep dreaming.

This is a special TT technique, in which Anquetil excelled. Are they banned in TT's ?

 

[coapman]

So every rider has to start the entire cycling process from scratch. Your comments sets the entire field of cycling science back a good 110 years.



Have you actually read all the research on pedalling technique? The testing of independent crank systems, rotor cranks, crank length and many other manipulations of the way we pedal and none have produced a better way of delivering power to the pedal than the natural method.

No all he needs are the basic objectives and the simple knack of generating maximal torque between 11 and 2 o'c. You call testing of rotorcranks biopace etc research on pedalling technique, this is equipment research where once again the same basic natural technique with its dead spot sector is being used. Anquetil's smooth technique is for TT's only, you need mashing and circular for the stop start nature of road racing and other requirements.

 

[FrankDay]

Another anecdote. A couple of days ago I got a call from another fellow making this change. He stated he was afraid to go to 130 crank length. The reason? He has seen so much speed gain from going to 150 he isn't sure his nervous system can take going much faster.

 

[coapman]

Another anecdote. A couple of days ago I got a call from another fellow making this change. He stated he was afraid to go to 130 crank length. The reason? He has seen so much speed gain from going to 150 he isn't sure his nervous system can take going much faster.

Was he referring to the cadence or the speed ?

 

[FrankDay]

Hadnt noticed that comment. Its an interesting question but I would add a word of caution. To avoid injury, Q factor should be based upon best tracking of the legs first before considering aerodynamics - if you can achieve both... Bonus!

I have some more observations regarding Q (including a little experiment I did) that I think is relevant to this discussion.

1. I am not aware of any data that suggests that 'Q' has any relation to injury rate. Let's look beyond cyclists and see what the range of Q is in athletes who use their legs for power generation. On the low end, runners. Runners tend to have a 'Q' of zero feet landing under the CG. Then, cyclists, whose feet are constrained to remain about 6 inches apart. Then, look at the stairmaster or elliptical trainer, where feet are constrained to be even further apart. Then, runners who are expected to change direction, where the distance between the feet can vary substantially. And, last, weight lifters, where feet are usually set quite wide. It seems to me that only in running straight forward is there any "naturally best" 'Q' and in all other activities we can adapt and perform well at a wide variety of stance widths.

2. Now for the experiment. Yesterday on my ride I decided I would see if I could feel how wide one might have to move the legs in order to see a drop in drag. So, while coasting (with both legs down, similar to the worst case, zero crank length, condition) I tried to rotate my knees out to see what would happen. It was amazing, an inch or so and the feel of the wind on the knees essentially disappeared. It was a huge change, way more than I ever anticipated. I then tried to repeat the test coasting with one leg forward and one leg back, as on regular cranks, and the feeling was similar. Seems the wind has to speed up as it goes around the frame of the bicycle and this increased speed gets directed to the legs when they are close to the frame. Based on this test it would be hard to imagine that substantial benefit could be had from tweaking this. This would be an easy experiment for any of you to repeat and report back your experience.

Further, later in the ride I was following one of those riders who have naturally bowed legs. In the past I always thought these riders had a natural aero disadvantage. Now, I think they may have a natural aero advantage. It would be worth testing as, it seems, would testing the effects of Q on drag.

 

[acoggan]

I have some more observations regarding Q (including a little experiment I did) that I think is relevant to this discussion.

1. I am not aware of any data that suggests that 'Q' has any relation to injury rate. Let's look beyond cyclists and see what the range of Q is in athletes who use their legs for power generation. On the low end, runners. Runners tend to have a 'Q' of zero feet landing under the CG. Then, cyclists, whose feet are constrained to remain about 6 inches apart. Then, look at the stairmaster or elliptical trainer, where feet are constrained to be even further apart. Then, runners who are expected to change direction, where the distance between the feet can vary substantially. And, last, weight lifters, where feet are usually set quite wide. It seems to me that only in running straight forward is there any "naturally best" 'Q' and in all other activities we can adapt and perform well at a wide variety of stance widths.

2. Now for the experiment. Yesterday on my ride I decided I would see if I could feel how wide one might have to move the legs in order to see a drop in drag. So, while coasting (with both legs down, similar to the worst case, zero crank length, condition) I tried to rotate my knees out to see what would happen. It was amazing, an inch or so and the feel of the wind on the knees essentially disappeared. It was a huge change, way more than I ever anticipated. I then tried to repeat the test coasting with one leg forward and one leg back, as on regular cranks, and the feeling was similar. Seems the wind has to speed up as it goes around the frame of the bicycle and this increased speed gets directed to the legs when they are close to the frame. Based on this test it would be hard to imagine that substantial benefit could be had from tweaking this. This would be an easy experiment for any of you to repeat and report back your experience.

Further, later in the ride I was following one of those riders who have naturally bowed legs. In the past I always thought these riders had a natural aero disadvantage. Now, I think they may have a natural aero advantage. It would be worth testing as, it seems, would testing the effects of Q on drag.

1. Knee width is not the same thing as Q. That is, you can ride with your feet close together yet your knees out, and vice-versa.

2. Numerous wind tunnel tests have shown that keeping your knees close together significantly reduces drag.

3. As previously mentioned, wind tunnel tests have also shown that having your feet close together (i.e., small Q) also reduces drag.

IOW, you're barking completely up the wrong tree here, Frank...

 

[acoggan]

2. Numerous wind tunnel tests have shown that keeping your knees close together significantly reduces drag.

See point #3:

http://web.archive.org/web/20050208083050/http://www.cervelo.com/tech/articles/article5.html

 

[acoggan]

An additional illustration: here's a pic of two cyclists with very low CdA values (0.198 m^2 and 0.204 m^2, the latter on friggin' drop bars no less!)...it is a bit hard to tell in the photo, but take note of their knee widths:

 

[FrankDay]

See point #3:

http://web.archive.org/web/20050208083050/http://www.cervelo.com/tech/articles/article5.html

From the article:

Horizontal torso. Defined by having your chest, or better yet, your back parallel to the ground, this is absolutely the most important element, as it can result in large magnitude changes in aerodynamic drag. Unfortunately, it may be the most difficult to achieve, because as you approach this position, your thighs start to hit your torso.…

Narrowly spaced elbow pads. Narrow elbows are an essential detail of an aero position. However, the magnitude of improvement is much less than what is achieved by adopting a horizontal torso position. … I do not believe these two findings are contradictory, rather, they indicate that once the torso is horizontal there is little you can do to improve or impair aerodynamic drag.

Knee width can change aerodynamic drag by up to half a pound. Pedaling with your knees close to the top tube is an essential part of good aerodynamics.

I am not so sure "barking up the wrong tree". Note that what i am looking at is using shorter cranks to help the rider achieve a more horizontal back (the most important variable according to your article) and then looking at leg width to help mitigate the increased leg drag that apparently comes from this change. The point in the article may very well be true using the standard configuration when using relatively long cranks and a flat back. I believe it is possible that there may be other considerations when one is riding much shorter cranks.

Fabian Cancellara can probably ignore my musings. Joe Blow age-grouper may have more to gain.

 

[FrankDay]

An additional illustration: here's a pic of two cyclists with very low CdA values (0.198 m^2 and 0.204 m^2, the latter on friggin' drop bars no less!)...it is a bit hard to tell in the photo, but take note of their knee widths:

Your point?

 

[CoachFergie]

From the article:
I am not so sure "barking up the wrong tree". Note that what i am looking at is using shorter cranks to help the rider achieve a more horizontal back (the most important variable according to your article) and then looking at leg width to help mitigate the increased leg drag that apparently comes from this change. The point in the article may very well be true using the standard configuration when using relatively long cranks and a flat back. I believe it is possible that there may be other considerations when one is riding much shorter cranks.

Fabian Cancellara can probably ignore my musings. Joe Blow age-grouper may have more to gain.

You could waste some more money and time in the tunnel testing. An age grouper will always have more to gain. That's a rather obvious statement.

 

[acoggan]

Fabian Cancellara can probably ignore my musings. Joe Blow age-grouper may have more to gain.

Everyone should ignore your musings.

 

[acoggan]

Your point?

That riders with low CdA values almost invariably have their knees close together.

 

[acoggan]

You could waste some more money and time in the tunnel testing.

I'm sure Frank will.

 

[FrankDay]

That riders with low CdA values almost invariably have their knees close together.

Huh? You just posted a picture of two riders, both with low CdA values and one with knees close together and one with knees far apart. How does that picture support your point.

Anyhow, it is quite possible that moving the knees together could lower the drag under certain circumstances just as it is possible that moving the knees apart could lower the drag under other circumstances. In our discussion while at the wind tunnel, in trying to explain what we were observing, it was the opinion of Len that the explanation was the legs were too close together. If that is truly the explanation then, it seems to me, that a possible fix was to move them further apart. His number was they had to be greater than 1.9 diameters apart (or away from the frame) to eliminate this effect.

 

[CoachFergie]

Huh? You just posted a picture of two riders, both with low CdA values and one with knees close together and one with knees far apart. How does that picture support your point.

Anyhow, it is quite possible that moving the knees together could lower the drag under certain circumstances just as it is possible that moving the knees apart could lower the drag under other circumstances. In our discussion while at the wind tunnel, in trying to explain what we were observing, it was the opinion of Len that the explanation was the legs were too close together. If that is truly the explanation then, it seems to me, that a possible fix was to move them further apart. His number was they had to be greater than 1.9 diameters apart (or away from the frame) to eliminate this effect.

Guess some people just have to learn the hard way.

 

[acoggan]

Huh? You just posted a picture of two riders, both with low CdA values and one with knees close together and one with knees far apart. How does that picture support your point.

Because both riders actually have their knees very close together (the lead rider just has massive quads).

Anyhow, it is quite possible that moving the knees together could lower the drag under certain circumstances just as it is possible that moving the knees apart could lower the drag under other circumstances. In our discussion while at the wind tunnel, in trying to explain what we were observing, it was the opinion of Len that the explanation was the legs were too close together. If that is truly the explanation then, it seems to me, that a possible fix was to move them further apart. His number was they had to be greater than 1.9 diameters apart (or away from the frame) to eliminate this effect.

Again, there are plenty of data showing that having your knees very close to the top tube leads to minimal drag. As well, there are data showing that the closer your feet are, the lower your drag (hence bikes w/ narrow b.b.s, e.g., GT SB-1 and SB-2, Walser, the special Trek TTX that was made for Armstrong
but ridden to an Olympic gold medal by Ekimov, etc.). You should therefore stop wasting everyone's time by pretending that this is not true.

 

[acoggan]

there are data showing that the closer your feet are, the lower your drag

From the Project 96 tests I mentioned previously:

(Funny, I never noticed before that the figure was mis-labeled! Obviously the top line corresponds to the highest speed, not the lowest speed, and vice-versa.)

 

[TarmacExpert]

Note that what i am looking at is using shorter cranks to help the rider achieve a more horizontal back (the most important variable according to your article)

IMO most people would be better served by training in the TT position and gradually increasing their saddle to pad drop as their flexibility improves, until the optimal drop is achieved. I have personally seen a huge improvement in my flexibility purely from doing all my training in the TT position, I don't do any other form of stretching. When I first started time trialling, with aerobars on my road bike, 40 minutes of riding in the aerobars absolutely killed my back for days afterwards. Now, after a lot of training in the TT position, I can ride in that position for all my training every day with no negative effects.

I suppose another way to get there would be for someone to take the initial "quick fix" of shorter cranks to get their torso into the optimal position, and then perhaps at monthly intervals after that they could increase crank length by 5mm at a time, lowering both saddle and pads by 5mm each time, to gradually get back to "normal" sized cranks with an optimal saddle to pad drop.

Incidentally, I thought Wiggins in the TT yesterday was the perfect example of the suppleness that everyone should be aiming for. Torso rock solid, great suppleness of hip movement, smooth and fluid pedalling action, didn't look to be fighting the bike at all, it was pure poetry in motion. Sanchez was the complete opposite, body moving all over the place, like he was fighting the bike all the way.