Power @ changing temperatures

[grom]

Power is Power

however it is 2celcius now it will be 6 celcius tomorrow and 10 on sunday
wind speed will be 9kph for all 3 days of course these are all predictions lol

my question is
if i ride the same course 3 days straight at 225 watts for 15 minutes will there be a speed fluctuation if so how much can one expect and is there a website to calculate this i would like to see what happens to speed when the temp goes from 2c to 22c when i ride the same exact route., also what would be the fastest temperature to ride if there is such a thing?

 

[ric_stern/RST]

Power is Power

however it is 2celcius now it will be 6 celcius tomorrow and 10 on sunday
wind speed will be 9kph for all 3 days of course these are all predictions lol

my question is
if i ride the same course 3 days straight at 225 watts for 15 minutes will there be a speed fluctuation if so how much can one expect and is there a website to calculate this i would like to see what happens to speed when the temp goes from 2c to 22c when i ride the same exact route., also what would be the fastest temperature to ride if there is such a thing?

yes there will be a change in velocity, and in very hot conditions your velocity will be highest even though your power maybe reduced, due to decreased air density (higher velocity).

You can model the various situations at www.analyticcycling.com

ric

 

[wilmar13]

yes there will be a change in velocity, and in very hot conditions your velocity will be highest even though your power maybe reduced, due to decreased air density (higher velocity).

You can model the various situations at www.analyticcycling.com

ric

Ok lets neglect the effects of air resistance. Say I am climbing a 12% grade that is 6km long. It sure seems like I can make more power if it is 16 Deg C than when it is 35 Deg (and go faster as well). Is this psychological, or is there a physiological reason, and if so what is it. Is it only that if you are overheated your performance suffers, or is there a relationship between body temp and performance i.e. you have the potential to make the same power until you over-heat regarless of outside temps (neglecting extreme cold) lets say a range between 0-40 deg C???

 

[velomanct]

just ride.


paralysis by analysis............i.e. overtraining more likely

 

[in.10.city]

just ride.


paralysis by analysis............i.e. overtraining more likely

But the impact of the viscosity of your chain lube and the rotational friction at the chainlink pins as they move through the drivetrain is such an enthralling topic... (I'm an engineer so it really is but I'm not ready to break out into a finite element modeling analysis of it right now ...)

 

[wilmar13]

So is there no difference in power output until your body begins overheating? How do you determine overheating?

 

[wilmar13]

just ride.


paralysis by analysis............i.e. overtraining more likely

I am not retarded. I am talking in terms of repeated generalities, not a one time "it seemed to be harder" type of deal.

 

[bikeguy]

This is why measuring training intensity by power alone is not good enough, power and heart rate (a measure of physiological stress, and maybe even a borg scale or rating of perceived exertion should be included too, and a temp recording both external and internal). For short sprints, hot is better because warm muscles can produce more power and air resistance is lower and there is no power loss because it's all anaerobic (all the best 100 m dash times were set when it was nice and warm) for longer distances the body will get hot if the outside temperature is above x and power output is y (will vary per individual) and may result in unconsciousness (some marathon runners have "conked" out during races, surprised it doesn't happen more to cyclists, maybe they're smarter). Marathons run in 28+ degrees are never near the world record times, 18 degrees or so seems to be optimal. Since cycling offers increased heat dissipation through the increased air flow over the cyclist the optimal temperature should be higher than that for marathons ( 2 hour duration events). In other words, if it's 35 degrees and your heart rate goes insane after 1 hr of riding hard but your power output is slightly lower than what you did 3 weeks ago at 25 degrees, then that *might* be a more intense training session then a slightly higher power output at 25 degrees. Difficult to quantify though, if even possible. But with certainty if you put out the same power at 35 degrees then what you did 3 weeks ago at 25 degrees, you are a fitter cyclist.

-Bikeguy