Ok… I’m trying to figure out my power output with analytic cyclings math thingy.
I posted a 2:28 bike split for 90km.
~10m a second
I’m 56kg
My bike probably weighs… let’s say 10kg with water bottles.
So… rider and bike about 66kg.
.4m squared frontal area (I’m not a big guy and ride aggressive)
Cadence is 85 average.
172.5 crank length
air density 1.1
everything else pretty much the same…
Now… someone tell me where I’m screwing up here? The power reading says 330.1 watts. No frickin way I can hold that wattage for a half-iron…
When I run the model using your data I get 135 watts. Which model are you running?
Frontal Area 0.40 m2
Coefficient Wind Drag 0.50 dimensionless
Air Density 1.226 kg/m3
Weight 65.0 kg
Coefficient of Rolling 0.004 dimensionless
Grade 0.000 decimal
Wind Resistance 12.3 kg m/s2
Rolling Resistance 2.5 kg m/s2
Slope Force 0.0 kg m/s2
Cadence 85. rev/min
Crank Length 172.5 mm
Pedal Speed 1.53 m/s
Average Pedal Force 96.7 kg m/s2
Effective Pedaling Range 70. degree
Effective Pedal Force 248.7 kg m/s2
Speed 10.00 m/s
Power 135.5 watts
hard work + quality training = improvement
Gee, what an insightful comment! You obviously know so much, I think I’m going to fire smartass and hire you as my coach.
The Big Cheese posted on this thread and wrote what’s above! :-)))
AhAH! I was able to copy it for ETERNITY! Another one of your testimonials! It’s going right into my webpage!
When I run the model using your data I get 135 watts. Which model are you running?
Frontal Area 0.40 m2
Coefficient Wind Drag 0.50 dimensionless
Too low for the CdA. CdA is Frontal Area times Coefficient of Drag. Yours is 0.20 – in Chris Boardman territory; way too low. It’s best to use analytic cycling by setting either Frontal Area or the Coefficient to equal 1.0, and then vary the other parameter in the 0.28 to 0.33 range (which is typical for triathletes).
The original poster’s problem is most likely the slope, but his CdA is too low. The default settings of 0.50 and 0.50 are too low for almost everybody, and need to be higher.
OK. you averaged 36.48km/hr for 90km. You said nothing about terrain or wind conditions. What I can tell you is on a flat road with zero wind conditions, 36.48km/hr equates to 252 watt output. From there you would have to factor in terrain and wind conditions. That’s very subjective, that’s why we use power meters!! Hope that helps you a little.
I’m simply reporting what the website calculated based on the rider’s input (which is a good example of why it’s fairly pointless to worry about calculated, rather than measured, watts).
Thanks everybody. I was just trying to ballpark what kind of power I was outputting out of curiosity. But there are too many other variables like wind and terrain.
Guess I better buy a power meter.
My power numbers are probably quite low due to my mass…
252 watts is based on indoor cycle with HP curves (converted to watts) for the fan used. All other parameters have been negated such as wind, terrain, air density, humidity, altitude, aerodynamics of body and bike, etc. So as you can see 252 watts is the ACTUAL wattage required to go that speed with no other parameters influencing it. As you know, all of the other factors will effect the wattage output to maintain that speed. When I’m outdoors on the road, my speed can vary all over the place for the same wattage output. That’s why your method of just calculating speed to wattage is not very accurate. The 252 was provided just to give him a base number for that speed. All other influences on watt output is subjective and ALWAYS dependent on many factors.
