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Unscientific test of best times on different bikes I've owned on Central Park Loop

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Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Unscientific test of best times on different bikes I've owned on Central Park Loop

Old 06-18-17, 04:35 PM
  #26  
CliffordK
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Originally Posted by kbarch View Post
As far as wind goes, I'll concede the point made by the diagrams @HTupolev provided. However, we're talking Central Park here, which is largely protected, and what counts as "windy" here really isn't much to begin with. It's not like the "experiment" was conducted on some windswept prairie.
Even a 5 MPH wind makes a significant difference to one's riding. In theory it should cancel out, so a circular wind pattern shouldn't be much of an issue, especially for a short ride. Although, I've had winds die out during a ride.

I have a short out and back test route that I ride a bit, about 11 miles total. So far, I think my fastest time was going into a headwind headed out, then returning with a tailwind. So, wind direction may not be completely irrelevant for loops or out and back rides.

I'm not sure if the headwind made a difference or not. The tailwind as one is hitting fatigue is nice. Plus, that ride has a slight climb to the turnaround, and the tailwind may be more efficient on the downhill than than the uphill.
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Old 06-18-17, 04:59 PM
  #27  
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Originally Posted by CliffordK View Post
Even a 5 MPH wind makes a significant difference to one's riding. In theory it should cancel out,
It doesn't cancel out, if you mean the speed you can expect from a given power.
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Old 06-18-17, 06:57 PM
  #28  
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Originally Posted by kbarch View Post
As far as wind goes, I'll concede the point made by the diagrams @HTupolev provided. However, we're talking Central Park here, which is largely protected, and what counts as "windy" here really isn't much to begin with. It's not like the "experiment" was conducted on some windswept prairie.
Depends on how much precision and accuracy you want. If you don't care/need much, it's not hard to get ballpark estimates. If you do, you need to be pretty anal about either controlling or measuring the things that affect the thing you're trying to estimate.

HR isn't one of those.
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Old 06-18-17, 07:14 PM
  #29  
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Originally Posted by HTupolev View Post
What you hope will happen:



What actually happens:



What actually actually happens:

This is amazing. Kudos.
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Old 06-18-17, 07:47 PM
  #30  
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Originally Posted by RChung View Post
Depends on how much precision and accuracy you want. If you don't care/need much, it's not hard to get ballpark estimates. If you do, you need to be pretty anal about either controlling or measuring the things that affect the thing you're trying to estimate.

HR isn't one of those.
Heart Rate is related to exertion which is related to power. So, it is an obvious candidate for a proxy measurement of power.

Originally Posted by wphamilton View Post
It doesn't cancel out, if you mean the speed you can expect from a given power.
One would expect say having a headwind going one direction (lose speed) and and a tailwind going the other direction (gain speed), the average effect would be zero.

But I agree, the result is probably not zero effect.

Sheldon Brown/Jobst Brandt discusses headwinds and crosswinds here: https://www.sheldonbrown.com/brandt/wind.html

The interesting thing is that a 90° sidewind is actually worse than no wind. One must have about a 10° tailwind ot break even, and even more to reap a benefit.
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Old 06-18-17, 07:59 PM
  #31  
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Originally Posted by CliffordK View Post
Heart Rate is related to exertion which is related to power. So, it is an obvious candidate for a proxy measurement of power.
A 'candidate' quickly ruled out by anyone who's spent much time riding with both.
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Old 06-18-17, 08:40 PM
  #32  
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Without a strain gauge power meter, an indoor velodrome, and identical frame measurements and componentry, these comparisons are uninteresting. Which is not to say that some frames are not faster than others. Inquiring minds want to know, but this is not how we find out.

On Saturday's long group ride, not having been on my single in quite a while, I was once again startled to see how much difference small changes in position make when going upwind at 20, even at the back of the line. Once again I was amazed to see how little attention many riders pay to efficient position and how much they pay to (and for) equipment. The more we learn, the more we forget.
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Old 06-18-17, 09:19 PM
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Originally Posted by Carbonfiberboy View Post
Without a strain gauge power meter, an indoor velodrome, and identical frame measurements and componentry, these comparisons are uninteresting.
Depends on what you want to know, and how much effort you're willing to put into finding it out with precision and accuracy. If what you're interested in is comparing two frames, or two wheels, or two helmets, or two skinsuits, obviously the components can't be identical.

And, there are ways to do this that don't require an indoor velodrome, and without a strain gauge power meter. They're a lot more hassle, and they require a lot more time, but it's certainly possible.
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Old 06-18-17, 09:20 PM
  #34  
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Originally Posted by CliffordK View Post
One would expect say having a headwind going one direction (lose speed) and and a tailwind going the other direction (gain speed), the average effect would be zero.

But I agree, the result is probably not zero effect.
Average of the two speeds, headwind and tailwind, is higher than the no-wind speed, but the overall time for the out and back will be longer.
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Old 06-18-17, 09:24 PM
  #35  
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Originally Posted by CliffordK View Post
Heart Rate is related to exertion which is related to power. So, it is an obvious candidate for a proxy measurement of power.
Good luck with that.
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Old 06-18-17, 10:04 PM
  #36  
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Originally Posted by RChung View Post
Depends on what you want to know, and how much effort you're willing to put into finding it out with precision and accuracy. If what you're interested in is comparing two frames, or two wheels, or two helmets, or two skinsuits, obviously the components can't be identical.

And, there are ways to do this that don't require an indoor velodrome, and without a strain gauge power meter. They're a lot more hassle, and they require a lot more time, but it's certainly possible.
Thank you for your interest in my comment.
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Old 06-18-17, 10:19 PM
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Originally Posted by CliffordK View Post
One would expect say having a headwind going one direction (lose speed) and and a tailwind going the other direction (gain speed), the average effect would be zero.
You'd expect so but it doesn't work out. Much like hills you spend more time going slow into a headwind which is what kills your average.

Assume a 5km out and back course. According to Bike Calculator at 240W you'd average 34.02km/h and it would take you 17m38s to cover the 10km. Do the same course with a 10km/h headwind out (10.69min) and 10km/h tailwind on the way back (7.39) and it's a total of 18m5s which is 27 seconds difference. The OP has a max difference of 38 seconds in his samples between his fastest and slowest sample.
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Old 06-18-17, 10:50 PM
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Originally Posted by CliffordK View Post
Heart Rate is related to exertion which is related to power. So, it is an obvious candidate for a proxy measurement of power.
Not really. My W/HR ratio varies widely depending on ambient temperature, hydration, how well rested I am, and pretty much every other continuously variable factor that influences HR. I see rides typically ranging between 1.3 and 1.6 W/HR, but have also seen as high as 2.1W/HR when I'm really overreached and the HR simply won't rise.

HR is a valuable metric, and can be used to help compile training stress, but is seldom indicative of power output.
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Old 06-19-17, 04:17 AM
  #39  
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In our little critique of the experiment design here, I think we're getting a too hung up on specific variables.

It's interesting that what's being compared is the BEST time for each bike. I'm convinced that some comparison of speed to watts is what we'd want to compare, and however accurately watts are measured, they are measured to the same degree of reliability in every case, so a large sample may provide sufficient confidence. But instead of looking at single best times, it would be better to look at total performance for each bike.

What would a chart look like if you plotted points for the time and average watts for each ride on a bike and drew a line between them, then overlaid or compared the graphs for each bike? With enough points, I imagine one could get a clear picture. Plot watts on the y axis and time to complete the loop on the x axis. Draw a line between the points for each bike. Variable conditions and inaccuracies in wattage measures may make such lines very jagged, but one would expect the lines for each bike to tend to slope down to the right. The "fastest" bike would be the one where this whole line tended to be most to the left.
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Old 06-19-17, 07:52 AM
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Originally Posted by kbarch View Post
What would a chart look like if you plotted points for the time and average watts for each ride on a bike and drew a line between them, then overlaid or compared the graphs for each bike? With enough points, I imagine one could get a clear picture. Plot watts on the y axis and time to complete the loop on the x axis. Draw a line between the points for each bike. Variable conditions and inaccuracies in wattage measures may make such lines very jagged, but one would expect the lines for each bike to tend to slope down to the right. The "fastest" bike would be the one where this whole line tended to be most to the left.
Have you tried this? If you have a power meter (and your method requires that you do) there are better ways to distinguish differences between bikes or equipment or position.
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Old 06-20-17, 05:35 AM
  #41  
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Originally Posted by mcours2006 View Post
...and the point is?
We love data?
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Old 06-20-17, 06:12 AM
  #42  
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How many smiles per mile though?
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Old 06-20-17, 07:14 AM
  #43  
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An interesting experiment, but what about the wheelset for each bike?
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