Does steep ascents kill your average mph more then steep descents helps it?
06-26-12, 07:48 PM
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Does steep ascents kill your average mph more then steep descents helps it?
I am working and living out of town in southwest VA and have my bikes with me, I have been exploring new roads and countryside and there are plenty of very steep hills to climb and zip down the other side, I have to use my bottom gear on a triple to climb some of these.
Well the result of this is my average mph is a least 2 mph less them when I am riding in East Tennessee which is hilly but less so.
So my questions,is if a hill is equal on the up and down hill part does the climb slow you down more then the down hill speeds you up? I will confess I am not a great climber at 210 lbs, that's a good chunk to drag up a hill.
Well the result of this is my average mph is a least 2 mph less them when I am riding in East Tennessee which is hilly but less so.
So my questions,is if a hill is equal on the up and down hill part does the climb slow you down more then the down hill speeds you up? I will confess I am not a great climber at 210 lbs, that's a good chunk to drag up a hill.
06-26-12, 07:50 PM
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Yes.
06-26-12, 08:32 PM
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Although, I agree with you never make up for speed lost ascending with descending. You get a lot more wind resistance at higher speeds which obviously affects descending more.
06-26-12, 08:34 PM
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This statement mathematically does not make sense. Distance covered is a big part of average speed.
Although, I agree with you never make up for speed lost ascending with descending. You get a lot more wind resistance at higher speeds which obviously affects descending more.
Although, I agree with you never make up for speed lost ascending with descending. You get a lot more wind resistance at higher speeds which obviously affects descending more.
.... "time" is pretty important too ..... then some quick simple math, and presto .... a result.
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Last edited by Homebrew01; 06-26-12 at 08:42 PM.
06-26-12, 08:42 PM
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06-26-12, 08:49 PM
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If the section was flat- lets say it took you 30 seconds to complete the first half, and another 30 to complete the second.
If the same section was a steep hill that ascended and descended at the same rate and distance- lets say 45 seconds to go up it, but 15 to go down.
This is how ive always thought about it. Not taking into account wind resistance or drag in any way that is...
If the same section was a steep hill that ascended and descended at the same rate and distance- lets say 45 seconds to go up it, but 15 to go down.
This is how ive always thought about it. Not taking into account wind resistance or drag in any way that is...
06-26-12, 09:00 PM
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Wrong. Your average speed is not the average of your speeds. If you go 10 mph for 20 minutes, and then 20 mph for 20 minutes, your average speed is not 15 mph, it's (3.33 miles + 6.67 miles) / 2/3 hour = 13.33 mph.
06-26-12, 09:04 PM
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If the section was flat- lets say it took you 30 seconds to complete the first half, and another 30 to complete the second.
If the same section was a steep hill that ascended and descended at the same rate and distance- lets say 45 seconds to go up it, but 15 to go down.
This is how ive always thought about it. Not taking into account wind resistance or drag in any way that is...
If the same section was a steep hill that ascended and descended at the same rate and distance- lets say 45 seconds to go up it, but 15 to go down.
This is how ive always thought about it. Not taking into account wind resistance or drag in any way that is...
For the same power output, a 6% grade will cut your speed in half. If that's the case, to keep the same average speed as a flat course, you'd have to climb to the top and then teleport to the bottom.
06-26-12, 09:06 PM
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Except it doesn't work that way.
For the same power output, a 6% grade will cut your speed in half. If that's the case, to keep the same average speed as a flat course, you'd have to climb to the top and then teleport to the bottom.
For the same power output, a 6% grade will cut your speed in half. If that's the case, to keep the same average speed as a flat course, you'd have to climb to the top and then teleport to the bottom.
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06-26-12, 09:07 PM
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How fat are you?
06-26-12, 09:07 PM
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Why does it matter? Avg speed is only pertinent on the same route with the same bike/components, same wind, etc. If improvement is really important to you then get a power meter...log your sleep/hydration/fuel/etc.
Or just relax and enjoy the riding...the avg speed obsession continues......amazing.
Or just relax and enjoy the riding...the avg speed obsession continues......amazing.
06-26-12, 09:07 PM
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Um duh
10 mile hill. Let say it takes you 2x as long to go up the hill, as it does going down the hill. Therefore 2/3 of the time spent on your ride was at the lower speed. Riding up hills kill your average speed way more than downhills help it unless the downhills are long enough or your speed high enough to make up for it. Theoretically you could pedal down the hill fast enough to make up the difference but not likey. The math will check out as well - knowing you average speed up said hill, you could calculate the speed needed going down the hill, that would bring your average speed up for the total ride to a higher speed than the average speed going up it and thus you solved the problem.
But then again average speed is really only useful to track a little performance improvement over a favorite route under relatively the same conditions. There are to many factors such as wind, elevation, incline, temperature that will effect performance. I typically ride 17-20mph average speed. If I ride for an hour into a 20 mph headwind, my average speed might be 10mph but I would guess I'd be pretty freaking tired!!
10 mile hill. Let say it takes you 2x as long to go up the hill, as it does going down the hill. Therefore 2/3 of the time spent on your ride was at the lower speed. Riding up hills kill your average speed way more than downhills help it unless the downhills are long enough or your speed high enough to make up for it. Theoretically you could pedal down the hill fast enough to make up the difference but not likey. The math will check out as well - knowing you average speed up said hill, you could calculate the speed needed going down the hill, that would bring your average speed up for the total ride to a higher speed than the average speed going up it and thus you solved the problem.
But then again average speed is really only useful to track a little performance improvement over a favorite route under relatively the same conditions. There are to many factors such as wind, elevation, incline, temperature that will effect performance. I typically ride 17-20mph average speed. If I ride for an hour into a 20 mph headwind, my average speed might be 10mph but I would guess I'd be pretty freaking tired!!
Last edited by ArchEtech; 06-26-12 at 09:28 PM.
06-26-12, 09:11 PM
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06-26-12, 09:12 PM
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except (3.33 miles + 6.67 miles) / 2/3 hour is, in fact, 15 mph.
06-26-12, 09:34 PM
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Check this bicycle speed and power calculator.
That shows that with the OP's 210 lb weight, he will generate 151W at 16 mph on 0% grade. At 3% grade, his speed will be 8.4 mph at 151W. At -3% grade, his speed would be 24.8 mph at 151W output.
If he rides a route with 1 mile flat, 1 mile with a 3% grade, 1 mile with a -3% grade, and the last mile flat at a constant 151W output you get:
[TABLE="width: 500"]
[TR]
[TD]mile[/TD]
[TD]1[/TD]
[TD]2[/TD]
[TD]3[/TD]
[TD]4[/TD]
[/TR]
[TR]
[TD]slope[/TD]
[TD]0[/TD]
[TD]3[/TD]
[TD]-3[/TD]
[TD]0[/TD]
[/TR]
[TR]
[TD]speed[/TD]
[TD]16.0[/TD]
[TD]8.4[/TD]
[TD]24.8[/TD]
[TD]16.0[/TD]
[/TR]
[TR]
[TD]time, min[/TD]
[TD]3.75[/TD]
[TD]7.14[/TD]
[TD]2.42[/TD]
[TD]3.75[/TD]
[/TR]
[/TABLE]
So the average speed is 14.07 mph. If he rode 4 miles on a flat course at a constant 151W output, he'd average 16 mph.
That shows that with the OP's 210 lb weight, he will generate 151W at 16 mph on 0% grade. At 3% grade, his speed will be 8.4 mph at 151W. At -3% grade, his speed would be 24.8 mph at 151W output.
If he rides a route with 1 mile flat, 1 mile with a 3% grade, 1 mile with a -3% grade, and the last mile flat at a constant 151W output you get:
[TABLE="width: 500"]
[TR]
[TD]mile[/TD]
[TD]1[/TD]
[TD]2[/TD]
[TD]3[/TD]
[TD]4[/TD]
[/TR]
[TR]
[TD]slope[/TD]
[TD]0[/TD]
[TD]3[/TD]
[TD]-3[/TD]
[TD]0[/TD]
[/TR]
[TR]
[TD]speed[/TD]
[TD]16.0[/TD]
[TD]8.4[/TD]
[TD]24.8[/TD]
[TD]16.0[/TD]
[/TR]
[TR]
[TD]time, min[/TD]
[TD]3.75[/TD]
[TD]7.14[/TD]
[TD]2.42[/TD]
[TD]3.75[/TD]
[/TR]
[/TABLE]
So the average speed is 14.07 mph. If he rode 4 miles on a flat course at a constant 151W output, he'd average 16 mph.
06-26-12, 09:34 PM
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True, I know what Kurt meant, but he messed up his example. He should have changed the time component, More like:
If you go 10 mph for 20 minutes, and then 20 mph for 10 minutes, your average speed is not 15 mph,
If you go 10 mph for 20 minutes, and then 20 mph for 10 minutes, your average speed is not 15 mph,
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06-26-12, 09:40 PM
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06-26-12, 09:41 PM
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06-26-12, 09:44 PM
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