The importance of crank length to the cyclist. - Page 117 - CyclingNews Forum

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  #1161  
Old 04-12-12, 11:10
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CoachFergie CoachFergie is offline
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Thank you very much Coach Fergie for making this point because it exactly makes my point.
You are assuming that the only consequence of being too low is a reduced hip angle. And that changing crank length is the only way to address the problem.
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  #1162  
Old 04-12-12, 14:24
coapman coapman is offline
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You have been perpetuating that nonsense for years and have never provided any evidence beyond what you think you observe from Jacques Anquetil. Think I will stick with published evidence over unproven theories thank you very much.


The nonsense is on the side of you and other coaches who never asked the question, what prevents me from applying max torque at 12, and then setting about solving it. All that's involved is a simple adjustment in the use of muscles. I missed this earlier, how did raising the front of your saddle by 2 degrees enable you to lower your stem by 4cm.
  #1163  
Old 04-13-12, 05:18
Tapeworm Tapeworm is offline
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Originally Posted by coapman View Post
The nonsense is on the side of you and other coaches who never asked the question, what prevents me from applying max torque at 12, and then setting about solving it. All that's involved is a simple adjustment in the use of muscles. I missed this earlier, how did raising the front of your saddle by 2 degrees enable you to lower your stem by 4cm.
How do you know you are applying max torque at these angles?
  #1164  
Old 04-13-12, 13:17
FrankDay FrankDay is offline
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Originally Posted by CoachFergie View Post
You are assuming that the only consequence of being too low is a reduced hip angle. And that changing crank length is the only way to address the problem.
I am not assuming anything. I, as do you, KNOW that being too low can compromise power. I, at least, have asked the question as to what might cause this and whether something might be done about it. I have, as a result, concluded that hip angle at TDC is a potential explanation. I have seen nothing to suggest this analysis is wrong.
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  #1165  
Old 04-13-12, 17:27
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Originally Posted by Tapeworm View Post
How do you know you are applying max torque at these angles?


Because of the direction in which the force is directed and the amount of resistance that has to be created to counteract this force.
  #1166  
Old 04-13-12, 17:40
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Where we may differ is my experience that there are more effective ways to achieve an optimal position in terms of aerodynamics and power delivery than changing crank length, putting the seat up, shifting it back, raising the bars and using a shorter stem. As mentioned previously I was able to lower my stem 4cm just by tilting my saddle up 2 degrees.


All riders have their own recognized standard saddle height, how can you raise the saddle height, (if that's what you mean by putting the seat up) and expect improvement without shortening your crank length. A person could interpret that statement of yours in two completely different ways
  #1167  
Old 04-14-12, 12:09
Tapeworm Tapeworm is offline
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Because of the direction in which the force is directed and the amount of resistance that has to be created to counteract this force.
Measured in any way or just assumed?
  #1168  
Old 04-14-12, 23:22
Night Rider Night Rider is offline
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No, I don't care about power for this test. The rider will be pedaling but we will not be testing power, which is typical for wind tunnel testing. I am only looking at rider aerodynamics. Once we establish what the aerodynamics of various positions are any rider can test their sustainable power in those positions outside of the wind tunnel which should allow them to assess what is best for them. It is not perfect but it is more information than they have now. I only have 2 hours. We are using a bike that will allow us to assess the full range of positions and rapid changing of components. The bike will not have any cables or brakes and I expect to be able to change crank length in less than 2 minutes. I am expecting to be able to test about a 9-10 inch difference in seat to handlebar drop. I also hope to get both road bike positions and aerobar positions. Again, we have a limited amount of time but I hope to get one run with just the bike alone so those of you concerned about this can assess the effects of the bike as it modifies the results. Again, I am primarily interested in assessing the effects of rider position on drag, generally agreed upon as the major component of drag in bicycle riders. This means the bike being used is not important.I will do my best. Not sure what the arrangement is.
Looking forward to it.
1. Power Meter, fair enough given your limitations in time.

2. Why not leave the cables and brakes on? You want to measure the effect of position changes of the rider on a bike that is to be ridden on the road. If you don't want brakes and cables test a track bike. I would be putting helmet and cycling gear on the rider and testing 1. In the drops 2. on the hoods 3. Sprinting out of saddle

3. I predict you are going to find minimal differences (either way) if you are using a rider in an optimal position to begin with. If you are using a 'Fred' type rider sitting upright to begin with then results could be all over the place and open to interpretation.
  #1169  
Old 04-15-12, 06:49
FrankDay FrankDay is offline
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1. Power Meter, fair enough given your limitations in time.

2. Why not leave the cables and brakes on? You want to measure the effect of position changes of the rider on a bike that is to be ridden on the road. If you don't want brakes and cables test a track bike. I would be putting helmet and cycling gear on the rider and testing 1. In the drops 2. on the hoods 3. Sprinting out of saddle

3. I predict you are going to find minimal differences (either way) if you are using a rider in an optimal position to begin with. If you are using a 'Fred' type rider sitting upright to begin with then results could be all over the place and open to interpretation.
Well, the test is completed and the results are VERY interesting and, I am sure, not what anyone would have predicted, including me. The results leave one particular unanswered question in my mind. And, we did use a track bike with a disk wheel in back and a zipp in front and an adjustable stem. We also tried to look at whether there was any benefit to using an aero helmet when very low and if so, how large. I am traveling right now and very tired so I will wait until I am home and have some time to review the data before posting the results. Stand by to be amazed.
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  #1170  
Old 04-16-12, 02:43
FrankDay FrankDay is offline
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Regarding the testing: We made one crucial error in our "design" that makes the data really look strange but in my 12 hour ride home I think I have figured it out such that it now makes sense to me and I think I learned a lot. Anyhow, it is complicated and I need a little time to sit down and put it all together. So I beg everyone to give me a little time.
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