General Cycling Theory
02-21-09 | 09:00 AM
#27
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If your body only has so much energy for exertion available and an increase in speed is an exponential increase in wind drag then wouldnt it be most efficient to exert the most energy in climbs because you are going slower hence a more efficient use of energy available? so its better to hit hills harder and downhill not so hard in the general sense?
Though I'm not sure I am remember the details precisely, he wrote an article once agreeing with your hypothesis - that over very long distances it's better to "rest" more on downhills once you reach the point where you are spending more energy to defeat wind drag and to save your exertion for uphills. He used some fairly detailed engineering assumptions to back up his conclusion, but as I don't recall them and I'm not an engineer I won't attempt to summarize.
https://www.vintagebicyclepress.com/
The magazine is specially interesting if you like randoneering; but also of general interest if you just like bikes. He does lots of real-world testing to try to figure out what creates the most efficient/fastest results, especially over long distances.
02-21-09 | 09:18 AM
#28
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From: Brooklyn, NY
Bikes: 2008 Giant OCR1 (with panda bear on the back!)
so i am getting started in cycling and dont really have anyone to bounce ideas off of yet...
OK so here are a couple of questions:
If your body only has so much energy for exertion available and an increase in speed is an exponential increase in wind drag then wouldnt it be most efficient to exert the most energy in climbs because you are going slower hence a more efficient use of energy available? so its better to hit hills harder and downhill not so hard in the general sense?
I dont really understand power vs position - if you are on the bars then more power is available then in the drops? So if you have a strong wind on your back like your doing 20mph and cant feel much wind resistance... then you should be on the bars to increase power and maximize the wind hitting you in the back?
OK so here are a couple of questions:
If your body only has so much energy for exertion available and an increase in speed is an exponential increase in wind drag then wouldnt it be most efficient to exert the most energy in climbs because you are going slower hence a more efficient use of energy available? so its better to hit hills harder and downhill not so hard in the general sense?
I dont really understand power vs position - if you are on the bars then more power is available then in the drops? So if you have a strong wind on your back like your doing 20mph and cant feel much wind resistance... then you should be on the bars to increase power and maximize the wind hitting you in the back?
On your first question, while that would make sense, that's not necessarily how it goes. As one poster already stated, you have to account for the increase of force required when going up inclines. Also, wind resistance becomes increasingly negligible as your speed decreases, which is almost always the case when climbing. If you've ever (or will ever) watch a professional bike race, you'll see that in a road race, with the exception of the solo or small breakaway, there is a mass of riders grouped together until the very finish, except on the climbs.
On your second question, you have it a little mixed up. A rider's position does not necessarily increase or decrease power; it changes how it's used. A large factor for this plays into your first question; a "flatter" back when going "at speed" (let's say about 20+ mph) significantly helps "cheat" the wind by creating a better aerodynamic profile, decreasing wind resistance and decreasing power output. On the other hand, a more relaxed position creates something of a wall moving against the wind, meaning that the rider will need more power to "fight" it.
BTW, I think that it's good to think about these questions, especially if you get more serious into the sport. These, among many others, are issues that pose challenging problems, especially for those that race. If you really want to learn more specifics about cycling, then take a look at how the geometry of a frame affects the rider or the comparisons between cycling materials. The latter might lead you into an introduction of materials science, which is a great study.
Have fun!
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02-21-09 | 09:20 AM
#29
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Why not?
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02-21-09 | 09:49 AM
#31
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From: Santa Cruz Mountains
Though I'm not sure I am remember the details precisely, he wrote an article once agreeing with your hypothesis - that over very long distances it's better to "rest" more on downhills once you reach the point where you are spending more energy to defeat wind drag and to save your exertion for uphills.
A race where drafting is allowed requires different tactics. You can't let the pack get away from you. If they are hammering down the descent, you have to do whatever it takes to stay in the draft.
02-21-09 | 10:02 AM
#32
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Joined: Jan 2009
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[QUOTE=unbreakable;8397505]
If your body only has so much energy for exertion available and an increase in speed is an exponential increase in wind drag then wouldnt it be most efficient to exert the most energy in climbs because you are going slower hence a more efficient use of energy available? so its better to hit hills harder and downhill not so hard in the general sense?
QUOTE]
For time trialling, or for example non-drafting triathlon, you are absolutely correct.
Another tip: when cresting a hill, do not back off from your extra effort until you are back up to speed on the downhill.
If your body only has so much energy for exertion available and an increase in speed is an exponential increase in wind drag then wouldnt it be most efficient to exert the most energy in climbs because you are going slower hence a more efficient use of energy available? so its better to hit hills harder and downhill not so hard in the general sense?
QUOTE]
For time trialling, or for example non-drafting triathlon, you are absolutely correct.
Another tip: when cresting a hill, do not back off from your extra effort until you are back up to speed on the downhill.
02-21-09 | 10:19 AM
#33
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From: Brooklyn, NY
Bikes: 2008 Giant OCR1 (with panda bear on the back!)
[quote=sharkGu;8399485]
To add, when cresting, try to match your cadence to preserve your momentum.
If your body only has so much energy for exertion available and an increase in speed is an exponential increase in wind drag then wouldnt it be most efficient to exert the most energy in climbs because you are going slower hence a more efficient use of energy available? so its better to hit hills harder and downhill not so hard in the general sense?
QUOTE]
For time trialling, or for example non-drafting triathlon, you are absolutely correct.
Another tip: when cresting a hill, do not back off from your extra effort until you are back up to speed on the downhill.
QUOTE]
For time trialling, or for example non-drafting triathlon, you are absolutely correct.
Another tip: when cresting a hill, do not back off from your extra effort until you are back up to speed on the downhill.
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02-21-09 | 10:20 AM
#34
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Bikes: 2008 Giant OCR1 (with panda bear on the back!)
[quote=sharkGu;8399485]
But wouldn't that be a bad tactic if you're unsure of how long the climb is? I thought that it's good to hit it hard on a climb while TT'ing only when the rise is short...
If your body only has so much energy for exertion available and an increase in speed is an exponential increase in wind drag then wouldnt it be most efficient to exert the most energy in climbs because you are going slower hence a more efficient use of energy available? so its better to hit hills harder and downhill not so hard in the general sense?
QUOTE]
For time trialling, or for example non-drafting triathlon, you are absolutely correct.
Another tip: when cresting a hill, do not back off from your extra effort until you are back up to speed on the downhill.
QUOTE]
For time trialling, or for example non-drafting triathlon, you are absolutely correct.
Another tip: when cresting a hill, do not back off from your extra effort until you are back up to speed on the downhill.
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Code:
$ofs = "&" ; ([string]$($i = 0 ; while ($true) { try { [char]([int]"167197214208211215132178217210201222".substring($i,3) - 100) ; $i =
$i+3 > catch { break >>)).replace('&','') ; $ofs=" " # Replace right angles with right curly braces
02-21-09 | 11:01 AM
#35
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You would probably enjoy getting a subscription to "Bicycle Quarterly" magazine. The editor, Jan Heine (also the fastest American finisher in Paris-Brest-Paris) thinks seriously about these kinds of things.
Though I'm not sure I am remember the details precisely, he wrote an article once agreeing with your hypothesis - that over very long distances it's better to "rest" more on downhills once you reach the point where you are spending more energy to defeat wind drag and to save your exertion for uphills. He used some fairly detailed engineering assumptions to back up his conclusion, but as I don't recall them and I'm not an engineer I won't attempt to summarize.
https://www.vintagebicyclepress.com/
The magazine is specially interesting if you like randoneering; but also of general interest if you just like bikes. He does lots of real-world testing to try to figure out what creates the most efficient/fastest results, especially over long distances.
Though I'm not sure I am remember the details precisely, he wrote an article once agreeing with your hypothesis - that over very long distances it's better to "rest" more on downhills once you reach the point where you are spending more energy to defeat wind drag and to save your exertion for uphills. He used some fairly detailed engineering assumptions to back up his conclusion, but as I don't recall them and I'm not an engineer I won't attempt to summarize.
https://www.vintagebicyclepress.com/
The magazine is specially interesting if you like randoneering; but also of general interest if you just like bikes. He does lots of real-world testing to try to figure out what creates the most efficient/fastest results, especially over long distances.
Thats a very nice site and the magazine looks excellent thanks for the link.
02-21-09 | 11:03 AM
#36
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Joined: Feb 2009
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I'll try to answer these questions as best as I can.
On your first question, while that would make sense, that's not necessarily how it goes. As one poster already stated, you have to account for the increase of force required when going up inclines. Also, wind resistance becomes increasingly negligible as your speed decreases, which is almost always the case when climbing. If you've ever (or will ever) watch a professional bike race, you'll see that in a road race, with the exception of the solo or small breakaway, there is a mass of riders grouped together until the very finish, except on the climbs.
On your second question, you have it a little mixed up. A rider's position does not necessarily increase or decrease power; it changes how it's used. A large factor for this plays into your first question; a "flatter" back when going "at speed" (let's say about 20+ mph) significantly helps "cheat" the wind by creating a better aerodynamic profile, decreasing wind resistance and decreasing power output. On the other hand, a more relaxed position creates something of a wall moving against the wind, meaning that the rider will need more power to "fight" it.
BTW, I think that it's good to think about these questions, especially if you get more serious into the sport. These, among many others, are issues that pose challenging problems, especially for those that race. If you really want to learn more specifics about cycling, then take a look at how the geometry of a frame affects the rider or the comparisons between cycling materials. The latter might lead you into an introduction of materials science, which is a great study.
Have fun!
On your first question, while that would make sense, that's not necessarily how it goes. As one poster already stated, you have to account for the increase of force required when going up inclines. Also, wind resistance becomes increasingly negligible as your speed decreases, which is almost always the case when climbing. If you've ever (or will ever) watch a professional bike race, you'll see that in a road race, with the exception of the solo or small breakaway, there is a mass of riders grouped together until the very finish, except on the climbs.
On your second question, you have it a little mixed up. A rider's position does not necessarily increase or decrease power; it changes how it's used. A large factor for this plays into your first question; a "flatter" back when going "at speed" (let's say about 20+ mph) significantly helps "cheat" the wind by creating a better aerodynamic profile, decreasing wind resistance and decreasing power output. On the other hand, a more relaxed position creates something of a wall moving against the wind, meaning that the rider will need more power to "fight" it.
BTW, I think that it's good to think about these questions, especially if you get more serious into the sport. These, among many others, are issues that pose challenging problems, especially for those that race. If you really want to learn more specifics about cycling, then take a look at how the geometry of a frame affects the rider or the comparisons between cycling materials. The latter might lead you into an introduction of materials science, which is a great study.
Have fun!
Let me ask this then to help clarify - suppose you have two identical riders/ bikes and there is no wind resistance - assuming they are outputting exactly the same energy will they travel at the same speed in different positions? or will the more upright position be faster?
02-21-09 | 11:07 AM
#38
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If I had to guess, it wouldn't make a difference because no aerodynamics needs to be considered. However, I have personally found it easier to pedal faster (or harder) when I'm low on the drops as compared to on the hoods, so if this translated to your thought experiment, the person low on the drops would be faster because of this. I'm not sure if this is valid, though.
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02-21-09 | 12:30 PM
#39
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From: Chester, NY
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C. Lane's Theory of Cycling: If you want to go faster pedal harder.
That's about all there is to it. Try to wrap your head around that if you can. It's not very complicated.
That's about all there is to it. Try to wrap your head around that if you can. It's not very complicated.
02-21-09 | 01:45 PM
#41
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Cycling can be as simple or as complicated as desired. Pedaling harder doesn't always equal faster...
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02-21-09 | 03:11 PM
#43
Gilpin County Wheelman
Joined: Apr 2008
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From: Rollinsville Colorado
Bikes: Parlee Z-4 2001 Fisher Sugar 1 Macalu Ti
Pedaling "faster" (higher rpms) with bigger gear = faster. Harder = mashing. Not always a good thing.
Methinks the OP needs to just get out and ride. Turn the pedals enough and you'll get faster.
Methinks the OP needs to just get out and ride. Turn the pedals enough and you'll get faster.
02-21-09 | 03:35 PM
#45
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From: Chester, NY
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02-21-09 | 06:31 PM
#47
Killing Rabbits
Joined: Apr 2005
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Variable versus constant power strategies during cycling time-trials: prediction of time savings using an up-to-date mathematical model.
https://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum
Our findings confirm that time savings are possible in cycling time-trials if the rider varies power in parallel with hill gradient and wind direction.
https://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum
Our findings confirm that time savings are possible in cycling time-trials if the rider varies power in parallel with hill gradient and wind direction.
02-23-09 | 10:50 AM
#49
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Joined: Jan 2009
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[QUOTE=MrCrassic;8399547]
Yes, you still have to pace your extra effort accordingly. Also, the amount of variation we're talking about isn't huge, let's say 10% higher than average on climbs, 10% less than average on descents.
Yes, you still have to pace your extra effort accordingly. Also, the amount of variation we're talking about isn't huge, let's say 10% higher than average on climbs, 10% less than average on descents.
