Is there a work output formula to compare flats vs hills ?
08-25-21, 03:17 PM
#1
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Is there a work output formula to compare flats vs hills ?
I am not a real cyclist. I only ride 5 mins to get my lunch. 3rd world commuter.
Today, I rode up a 10% hill that was about .2 miles long.
During this leg burning episode, all I could think was, "I wonder how much flat biking this work is equal to"
Like is 10% for .2 miles the same as riding flat for 1 mile ?
Decline riding is like negative infinity division by zero work.
Is there a conversion factor ?
Today, I rode up a 10% hill that was about .2 miles long.
During this leg burning episode, all I could think was, "I wonder how much flat biking this work is equal to"
Like is 10% for .2 miles the same as riding flat for 1 mile ?
Decline riding is like negative infinity division by zero work.
Is there a conversion factor ?
08-25-21, 03:23 PM
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08-25-21, 03:24 PM
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Yes, but the conversion is complicated. You have to convert the slope of the hill to ASVG (Air Squat Vertical Gain), and the distance to BPE (Bench Press Equivalent). Once you have those numbers, conformal mapping will give you the answer you're looking for.
On edit: Damn, I'm too slow for this sport (online forums).
On edit: Damn, I'm too slow for this sport (online forums).
08-25-21, 03:27 PM
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08-25-21, 03:29 PM
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Here is an example of a calculator. I’m sure it’s not perfect but will give you an idea…
https://www.omnicalculator.com/sports/cycling-wattage
Otto
https://www.omnicalculator.com/sports/cycling-wattage
Otto
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08-25-21, 03:40 PM
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Yes, the formula is: riding up hills is harder than riding on flat ground.
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08-25-21, 03:43 PM
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100 vertical feet is equal to 1 mile on the flat for basic cyclists and 200 feet for very fit rider. Not talking TdF racers. YMMV
08-25-21, 03:46 PM
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Here is an example of a calculator. I’m sure it’s not perfect but will give you an idea…
https://www.omnicalculator.com/sports/cycling-wattage
Otto
https://www.omnicalculator.com/sports/cycling-wattage
Otto
08-25-21, 04:01 PM
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Otto
Last edited by ofajen; 08-25-21 at 04:04 PM.
08-25-21, 04:03 PM
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This is what power meters do.
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08-25-21, 04:29 PM
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It gives you power, which is the rate at which work is being done. At a particular power output, total work would be power multiplied by time. For example, power (in watts) multiplied by time (in seconds) gives work (in joules). Depending on your particular metabolism, one dietary calorie equates to roughly 4000 joules.
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But, for a constant speed, each 1% of incline is a 10x increase in work.
But, if I plug in wild guess speed estimates, the data makes no sense
15mph at 0% = 100w
3mph at 10% = 100w
No way slow 10% is the same work at easy flat riding
08-25-21, 05:22 PM
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None of those formulas work unless you ride longer than 5mins!
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08-25-21, 05:35 PM
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I see. The variable is then speed. The 2 inclines will have varying speeds.
But, for a constant speed, each 1% of incline is a 10x increase in work.
But, if I plug in wild guess speed estimates, the data makes no sense
15mph at 0% = 100w
3mph at 10% = 100w
No way slow 10% is the same work at easy flat riding
But, for a constant speed, each 1% of incline is a 10x increase in work.
But, if I plug in wild guess speed estimates, the data makes no sense
15mph at 0% = 100w
3mph at 10% = 100w
No way slow 10% is the same work at easy flat riding
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08-25-21, 05:38 PM
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08-25-21, 05:40 PM
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Hills > flats
08-25-21, 05:44 PM
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08-25-21, 06:57 PM
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I see. The variable is then speed. The 2 inclines will have varying speeds.
But, for a constant speed, each 1% of incline is a 10x increase in work.
But, if I plug in wild guess speed estimates, the data makes no sense
15mph at 0% = 100w
3mph at 10% = 100w
No way slow 10% is the same work at easy flat riding
But, for a constant speed, each 1% of incline is a 10x increase in work.
But, if I plug in wild guess speed estimates, the data makes no sense
15mph at 0% = 100w
3mph at 10% = 100w
No way slow 10% is the same work at easy flat riding
Cycling: Uphill and Downhill
The gravity term is giMs, where g is gravitational constant, I is incline, M is combined mass of bike and rider and s is speed of bike.
Put in the SI units carefully amd you will get the right number. I climb at about 300 watts on most hills and about 250 watts will usually be gravity work, but it varies depending upon if it’s shallow enough that my speed makes the air drag term significant. At 16 mph, I would be needing about 135 watts for the air drag and rolling friction terms.
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Last edited by ofajen; 08-25-21 at 07:01 PM.
08-25-21, 07:18 PM
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$299 is the conversion rate.
08-26-21, 01:37 AM
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Two threads because you went up a short hill? Knock it off.
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08-26-21, 02:22 AM
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If you start and finish in the same place for every hill that you struggled up there was a slope for you to coast down.
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08-26-21, 03:22 AM
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Here’s another simple calculator to play with that shows distance vs power and energy etc.
Bike Calculator
Bike Calculator
08-26-21, 05:05 AM
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Mathematically true, but the grades up can be very different from the grades down. If it's 10 percent going up and 1 percent going down, I don't think I'm going to coast any of that.