The importance of crank length to the cyclist.

[FrankDay]

It is hideously bad but is crank length the only option to improve his position?

I donno if it is the only option but would you deny it is an option? Why wouldn't one want to use all the options available to them to optimize the potential?
Edit #2: Raynard had a 4:28:38 bike split for the 112 miles. That had to be done on raw power with that position. Think how fast he would have gone if he had been the least bit aerodynamic. But, according to you Fergie, his PM would have shown a great "performance" because that power number had to be huge.

 

[CoachFergie]

All the options I have used haven't required the changing of cranks to achieve an aerodynamic position where they can maintain their power.

Remember Onetrack claimed huge potential for aerodynamic savings and you claimed an increase in power in the OP.

Have yet to see any real evidence of this yet.

 

[FrankDay]

All the options I have used haven't required the changing of cranks to achieve an aerodynamic position where they can maintain their power.

Remember Onetrack claimed huge potential for aerodynamic savings and you claimed an increase in power in the OP.

Have yet to see any real evidence of this yet.

Are you denying that crank length is a potential option for improving aerodynamics? We all have sort of figured out that you have never used this in any of your athletes. But, do you deny that it is a potential option for others to use?

 

[CoachFergie]

Edit #2: Raynard had a 4:28:38 bike split for the 112 miles. That had to be done on raw power with that position. Think how fast he would have gone if he had been the least bit aerodynamic. But, according to you Fergie, his PM would have shown a great "performance" because that power number had to be huge.

Not really, if doing a comparison of power to frontal area with faster riders they would have a better performance.

Measuring performance is one thing but performance measures need to be relevant. Like measuring power to weight in a flat race.

 

[CoachFergie]

Are you denying that crank length is a potential option for improving aerodynamics?

No.

We all have sort of figured out that you have never used this in any of your athletes. But, do you deny that it is a potential option for others to use?

If it's okay with you I will go for the methods of improving aerodynamics and maintaining power delivery that don't require changing cranks, whacking the seat up and back, lifting the stem and shortening it or having to relocate the cleats under the arch.

For 99% of the people I have set up with aerodynamics and power delivery as a goal the biggest cost was their time.

 

[FrankDay]

No.



If it's okay with you I will go for the methods of improving aerodynamics and maintaining power delivery that don't require changing cranks, whacking the seat up and back, lifting the stem and shortening it or having to relocate the cleats under the arch.

For 99% of the people I have set up with aerodynamics and power delivery as a goal the biggest cost was their time.

You can do whatever you think is best for you and your athletes. However, I am glad to see that you don't deny that changing crank length is a potential way that athletes might use to optimize their position/power potential, which is part of what I said when I started this thread.

 

[Oldman]

You can do whatever you think is best for you and your athletes. However, I am glad to see that you don't deny that changing crank length is a potential way that athletes might use to optimize their position/power potential, which is part of what I said when I started this thread.

And most of us have agreed. You continue to argue that your product provides both benefits when most others say they're not necessary and reduced crank lengths are not the panacea; particularly expensive ones.

History and performance says you are not correct.

 

[Martin318is]

Measuring performance is one thing but performance measures need to be relevant. Like measuring power to weight in a flat race.

I assume you wrote that because it IS relevant? Its not as relevant as in a hilly race obviously but there isn't really a coincidence that larger riders perform better on flat or slightly rolling terrain than small climbers.

Being heavier has costs in cross section but benefits in things like inertia... just sayin

 

[CoachFergie]

You can do whatever you think is best for you and your athletes. However, I am glad to see that you don't deny that changing crank length is a potential way that athletes might use to optimize their position/power potential, which is part of what I said when I started this thread.

Where did optimization and power potential come into my agreeing with you that putting shorter cranks could potentially improve aerodynamics?

You have supplied no evidence of that.

My riders and people who consult for position advice don't settle for what I think. I have to provide hard data.

 

[CoachFergie]

I assume you wrote that because it IS relevant? Its not as relevant as in a hilly race obviously but there isn't really a coincidence that larger riders perform better on flat or slightly rolling terrain than small climbers.

Being heavier has costs in cross section but benefits in things like inertia... just sayin

Isn't as relevant. In a small study I have done collecting power meter data from flat races power to weight was not as relevant to performance or outcome as absolute power or allometric scaled power.

 

[FrankDay]

And most of us have agreed. You continue to argue that your product provides both benefits when most others say they're not necessary and reduced crank lengths are not the panacea; particularly expensive ones.

History and performance says you are not correct.

What on earth does this thread have to do with my product other than we offer the option for the user to experiment with this while also learning how to pedal in the PC fashion (which I think is a separate benefit)? The potential benefits of shorter cranks should accrue to anyone, whether they are a PC'er or not. And, this experiment doesn't have to cost an arm and a leg - C. Ogden won IM Western Australia on 145mm cranks he picked up off the internet for $22. It might be that a PC'er might be able to go shorter than a non-PC'er but that is speculation on my part.

 

[CoachFergie]

What on earth does this thread have to do with my product

Oldman didn't say anything about independent cranks. You do market a crank that has adjustable lengths which just also happens to offer independent moving crank arm option.

 

[CoachFergie]

I find it amusing that this chap will drop a grand to experiment with independent cranks but clearly hasn't spent 5 mins on a windtrainer beside a mirror and thought: "s**t I'm not all that aero".

 

[Martin318is]

Isn't as relevant. In a small study I have done collecting power meter data from flat races power to weight was not as relevant to performance or outcome as absolute power or allometric scaled power.

Yep I assumed that was what you meant. I'm just trying to pull things back from the language of absolutes. I thought it would be good to highlight that this was one where you yourself were probably not trying to make an absolute statement while at the same time opening a potential area for attack from others by accident.

I think that if everyone takes a step back and reads over their upcoming posts thinking about that before submitting then there is a likelihood that a lot of the heated disagreement would be replaced by at least gruding acceptance - in both directions.

 

[Martin318is]

I find it amusing that this chap will drop a grand to experiment with independent cranks but clearly hasn't spent 5 mins on a windtrainer beside a mirror and thought: "s**t I'm not all that aero".

you could say the same about the frame, wheels, etc. That said, I always find it difficult to make absolute pronouncements about the riding position of someone from a single photo.

Last year people were attacking Carlos Sastre for his stem length, etc on the basis of 3 photos that showed him climbing with his hands an inch or so behind his brakehoods.

Are there more photos of this rider or even better some video? He is showing a fair bit of strain in that image and I wonder whether he isn't being pulled into a less aero position by the effort...

 

[CoachFergie]

you could say the same about the frame, wheels, etc. That said, I always find it difficult to make absolute pronouncements about the riding position of someone from a single photo.

True.

I have been asked to test a top line road bike as used by a current world road race champion as they claim it is X amount more aero than other bikes. Not sure what me riding one bike with a power meter is going to tell me unless I compare it to all the bikes out there.

Manufacturers constantly make these claims. A set of wheels will take 60sec off your 40km TT but the comparison is with a set of box section clinchers. One of my riders asked what the benefit would be in buying a Campag Ghibli Disc over his Campag Bora wheels. I worked out for 16km a maximum benefit of 1.67 seconds. He still spent the $4000 on the wheel.

At least for things like wheels or tyres there are independent power or wind tunnel tests that can steer you in the right direction.

Are there more photos of this rider or even better some video? He is showing a fair bit of strain in that image and I wonder whether he isn't being pulled into a less aero position by the effort...

Right, it is only one shot and I don't perform bike set ups from photos or even videos unless it's one of my International clients and even then I would prefer they find someone suitable locally. But I think some flexibility tests and 10mins work with an allen key would be the place to start rather than changing cranks, whacking the seat back and up, shortening the stem and lifting it up.

 

[FrankDay]

Where did optimization and power potential come into my agreeing with you that putting shorter cranks could potentially improve aerodynamics?

In post 702 you admitted that shorter cranks have the potential to improve aerodynamics and now, are you denying that they have the potential to help optimize the total power/aerodynamics potential of the rider?

 

[CoachFergie]

Yep I assumed that was what you meant. I'm just trying to pull things back from the language of absolutes. I thought it would be good to highlight that this was one where you yourself were probably not trying to make an absolute statement while at the same time opening a potential area for attack from others by accident.

Just doing a write up for a wee study I have done and calculating p values, confidence intervals and effect sizes I am understand the need to avoid absolutes.

 

[FrankDay]

He is showing a fair bit of strain in that image and I wonder whether he isn't being pulled into a less aero position by the effort...

Since, his arms are in the aero pads I doubt this picture is far from his "best" position. Other pictures show a similar postion. I would expect him to be "straining" also with a 4:30 bike split in that position because it had to come mostly from raw power.

 

[onetrack]

Looking at the riders from Men's World Time Trial Champs who were all using 175mm or longer cranks they all appear to have very aerodynamic positions and I'm sure all spent considerable time in the wind tunnel. Where would this huge potential for aerodynamic savings come from?

I'm glad you asked. anatomy.

Variations in anatomy, the way a rider's back flexes, broadness of rib cage, tibia length all factor in how low your handle bar can go weather it be a matter of comfort, power generation or thighs hitting ribs. crank length handles this nicely. shortening the cranks 20mm allows the relative seat/handlebar drop of an extra -4cm! Spend all the time in a wind tunnel you want, if your flexibility, tibia length, rib cage shape only allows so much drop at a given crank length and it's likely you have room for improvement if your shoulders aren't level with your hips.

I was at my max drop till I rode shorter cranks, short cranks allowed another 37mm of drop (ignoring that I ride in the drops more now). It just so happened my hill times also improved with the change to shorter cranks.

 

[CoachFergie]

In post 702 you admitted that shorter cranks have the potential to improve aerodynamics and now, are you denying that they have the potential to help optimize the total power/aerodynamics potential of the rider?

Yes Frank the two things are not the same.

Shorter cranks may allow a rider to achieve a flatter back but I have no data (published, un-published and even subject to confidentiality agreement) to pass judgement on the effect on power either way. Do you?

I have used other methods to successfully flatten the back and maintain the power delivery that have been tested in the wind tunnel and in the field.

 

[FrankDay]

Yes Frank the two things are not the same.

Shorter cranks may allow a rider to achieve a flatter back but I have no data (published, un-published and even subject to confidentiality agreement) to pass judgement on the effect on power either way. Do you?

I have used other methods to successfully flatten the back and maintain the power delivery that have been tested in the wind tunnel and in the field.

So, let me get this straight. You do believe that shorter cranks could help improve overall aerodynamics but you do not believe they could help improve the overall power/aerodynamics tradeoff? Is that correct?

 

[Martin318is]

Since, his arms are in the aero pads I doubt this picture is far from his "best" position. Other pictures show a similar postion. I would expect him to be "straining" also with a 4:30 bike split in that position because it had to come mostly from raw power.

but once again - please refer to my entire post. The point I actually raised is that with only one photo to look at we have no idea if he was in this particular position for an extended period or whether it was just a moment in time between positions.

Asside form the Sastre example another would be Alberto Contador. His position often seems to be continually evolving because he seems to slide down to the nose of the saddle and 'scoot' back up every 10seconds or so. If you take one photo of him, which position is he actually riding in?

I am not arguing that his position looks less than ideal in that photo. I was just pointing out the above.

 

[FrankDay]

but once again - please refer to my entire post. The point I actually raised is that with only one photo to look at we have no idea if he was in this particular position for an extended period or whether it was just a moment in time between positions.

Asside form the Sastre example another would be Alberto Contador. His position often seems to be continually evolving because he seems to slide down to the nose of the saddle and 'scoot' back up every 10seconds or so. If you take one photo of him, which position is he actually riding in?

I am not arguing that his position looks less than ideal in that photo. I was just pointing out the above.

With the pads in that position it is not possible for him to lower his front anymore than it is.

 

[CoachFergie]

I'm glad you asked. anatomy.

Variations in anatomy, the way a rider's back flexes, broadness of rib cage, tibia length all factor in how low your handle bar can go weather it be a matter of comfort, power generation or thighs hitting ribs. crank length handles this nicely. shortening the cranks 20mm allows the relative seat/handlebar drop of an extra -4cm! Spend all the time in a wind tunnel you want, if your flexibility, tibia length, rib cage shape only allows so much drop at a given crank length and it's likely you have room for improvement if your shoulders aren't level with your hips.

I was at my max drop till I rode shorter cranks, short cranks allowed another 37mm of drop (ignoring that I ride in the drops more now). It just so happened my hill times also improved with the change to shorter cranks.

I have been riding in a position that I was struggling to get high enough in. After a 30sec change in seat position with a 50 cent allen key was able to lower my bars 4cm as well and 2 months on have no problem riding in that position. More speed through lower frontal area (no data sorry) and no loss in power (as recorded by a power meter not my imagination).

My hill times have improved because I changed my gearing to allow a higher cadence on climbs. Cost me $90 for the cassette (which was due anyway) and took 5 minutes to change.

Neither required huge changes to my bike and cost ****** all with minimal time investment.