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# Q About Power Wattage for Math People, Scientists, Geeks.

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# Q About Power Wattage for Math People, Scientists, Geeks.

10-01-09, 10:23 AM
#1
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Q About Power Wattage for Math People, Scientists, Geeks.

After reading a statement by Homey in another thread about power output, I was wondering if someone could figure it out by distance, speed, weight, gradient. I've seen it before but have no idea myself.

Lets say I've done an 8 mile climb, 6% gradient, 56 minutes, at 225 lbs. Could you figure out how my power wattage for the ride? 2200 feet elevation gain.

OR:

21 miles, 2:06 time, 225 lbs with a 4800 ft gain. 5% gradient.

It would be cool to know but no way am I spending big bucks for a powertap to find out something that would tickle me for a day or two!
10-01-09, 10:27 AM
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https://bikecalculator.com/wattsUS.html

Example 1, 298 avg watts.
Example 2, 302 avg watts.

Assuming my math is right anyway.

Let's see, weight is 102 kilos, so this is 2.94 watts/kilo. Not too bad.
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10-01-09, 10:34 AM
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Originally Posted by JoelS
https://bikecalculator.com/wattsUS.html

Example 1, 298 avg watts.
Example 2, 302 avg watts.

Assuming my math is right anyway.

Let's see, weight is 102 kilos, so this is 2.94 watts/kilo. Not too bad.
That's more than respectble. Mini wildabeast in some circles.
10-01-09, 11:33 AM
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Originally Posted by JoelS
The gold standard for web-based power calculation seems to be this one. It takes aerodynamic factors into account and is supposed to be pretty accurate. Or at least that's what everybody tells me...
10-01-09, 12:51 PM
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using those calculators on my last ride i avg 357avg watts output

i think the best way to really figure it out is to buy a computer that will monitor it for you .... from what i've seen most of the calculators are off by some degree
10-01-09, 02:47 PM
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Originally Posted by txvintage
That's more than respectble. Mini wildabeast in some circles.
Is there some rating scale that shows bad, good, average ratings ? Or a n estimate just off the top of your head?
10-01-09, 05:32 PM
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10-01-09, 07:19 PM
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If you want to know everything about power output and Watts/kg you should venture into the racing forum.
But since I'm 2.9W/kg myself I can tell you with 100% assurance, you are cat4 material
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10-01-09, 08:01 PM
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FWIW, 400 watts equates to just over 1/2 horsepower, and 0.72727 foot ponds/second torque

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10-01-09, 08:03 PM
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Originally Posted by Scummer
If you want to know everything about power output and Watts/kg you should venture into the racing forum.
But since I'm 2.9W/kg myself I can tell you with 100% assurance, you are cat4 material
You think so?......I did think about racing a few years back. I went out to some crit training rides just to gauge myself. I did a pull then peeled off to the backof maybe 30 guys. About 10 seconds after the fast guys took off.

The others didn't respond so I asked the guys if they were going to try to catch them. They said,"they're too fast!". I went around and tried but no way could I close a 50 yard gap alone. I closed about half some but blew up before I could catch up.

Next week I kept my eyes open, sure enough, same split but I jumped on this time. maybe 10 guys took off. It was a 3 mile loop, and the ride was 10 laps (30 miles). About half way thru only 4 of us left. I did my scheduled pulls but one cheeser wouldn't...He finally started pulling when there was only 2 laps left cause the other 2 got upset with him.

With 2 laps left, we almost lapped the other group of 20. One dude was a total badarse rider. The other was cool but very strong. Finally I dropped off with 5 miles left. The cool dude dropped back and said hop on, can't stop now. I did then he pulled me back up again. He kept enouraging me but finally with 2 miles, I just couldn't hang.

I was actually shocked that I had almost lapped the guys on team bikes and uniforms on my old Cannondale and a tanktop....After the ride guys were asking, what team did I ride with? It was a chuckle having a big group of guys asking, "what's your name again?". Mr Beanz dammit!...Funny thing was they all had sweet wheels and team bikes but were admiring the wheel that I built with a \$25 clearance rack Deep V.....I was actually shocked just to keep up with anybody!

First time I had ever taken pulls doing 26 mph repeatedly. I think with some training, I'd do ok! I did go check out some races hoping to try but just didn't interest me. I tell my wife, "I just can't see mysellf in a race kit"

But if I were to race, I think I'd do a timetrial. I tested myself and did a 22.6 average for a flat 10 mile ride from a dead stop. I'd prolly get killed by the regulars but it would be fun to try. I'd prolly wear a tanktop too!

Just might be my goal for when I turn 50 to keep myself in some kind of shape for the later years.
10-01-09, 11:10 PM
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Well, according to the Bike Speed and Power website here is what we got:
tandem (racing) two riders (thus the 500lbs approx).
Rider's Height 75
Rider's Weight 500
Bicycle Weight 26
Air Temperature 68
Height above SeaLevel 0
Wind Speed 0

On narrow racing tires, with a speed of 28mph (that's what we averaged across most of Kansas)

535 watts

For what it's worth...
10-02-09, 12:09 AM
#12
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^^^^^^Using that calculator puts me just below 400W. That would be 5W/kg. I'm not that good. Calculator is wrong. The "analytic cycling" one seems better. more realistic for me to be under 300W.
10-02-09, 12:40 AM
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This is from Bike Calculator

Speed 28 mph
Rider weight 500 lbs
Bicycle weight 26 lbs
Tires Clinchers
Position Aerobar
Distance 15 miles
Temperature 72 F
Elevation 100 ft
Trans. Efficiency 95 %
Predictions below:
Power 439 watts
Time 32:14 minutes
Calories 809 KCal
Weight loss .23 lbs

again, for what it's worth...
10-02-09, 12:55 AM
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I couldn't get the analytical cycling site to work for me tonight...

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