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From: Jeff Liebermann <jeffl@cruzio.com>
Newsgroups: rec.bicycles.tech
Subject: Re: Today's Ride
Date: Sun, 22 Jun 2025 10:25:45 -0700
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On Sun, 22 Jun 2025 10:30:00 -0400, zen cycle
<funkmasterxx@hotmail.com> wrote:

>On 6/21/2025 9:07 PM, Jeff Liebermann wrote:
>> On Sat, 21 Jun 2025 20:12:02 -0400, Frank Krygowski
>> <frkrygow@sbcglobal.net> wrote:
>> 
>>> On 6/21/2025 4:59 PM, cyclintom wrote:
>>>> We had a 25 mph headwind all the way out with 35 mph gusts.I wouold be riding along working pretty hard at 12.5 mph and as the gusts hit I would be instantly at 11 mph. Normally this would be somewhat compensated for by a tailwind on the way back but I guess it was more a cross wind as we turned back.
>>>
>>> Congratulations! 12.5 mph into a 25 mph headwind takes quite a bit of
>>> power, something close to 400 Watts. I'm very amazed a guy your age can
>>> do that!
>>>
>>>> 23 miles and average speed of only 8.18 miles per hour average ...
>>>
>>> Ah. 8.18 mph sounds much more believable. That might be around 200 Watts.
>> 
>> This is easier and includes more parameters.
>> I had to guesstimate on some of the values because Tom doesn't
>> disclose which bicycle he's riding, how much he weight, roadway slope,
>> etc.
>> 
>> <https://www.gribble.org/cycling/power_v_speed.html?units=imperial&rp_wr=199.999&rp_wb=17&rp_a=5.9998&rp_cd=0.63&rp_dtl=2&ep_crr=0.01&ep_rho=0.078035&ep_g=0&ep_headwind=25&p2v=200&v2p=22>
>> To maintain a ground speed of 12.29 mph into a 25 mph headwind, Tom's
>> pedaling needs to produce 396.28 watts of power.
>> (Punch the Units: Metric button to change everything to metric).
>> 
>> At 8.18 mph, 217 watts of power is required.  Yeah, that's more
>> realistic.
>
>Not for an 80 year old. Tommy insists he can only sustain 90 watts.
>https://rec.bicycles.tech.narkive.com/q35jywK7/average-speeds
>"It appears that good riders at 60 can average about 90 watts of full 
>time power. "

Oops.  There was no provision in the Steve Gribble online calculator
for power reduction with increasing age.  More accurately, I didn't
notice and forgot about age.  What I did was use the results to
determine what might be considered "realistic".  Unfortunately, the
data was not broken down by age.  The data seemed to be distributed
for all ages, so I just looked for the 50% median peak in the
distribution curve for males, which is about 260 watts.  

"How does your cycling power output compare?"
<https://www.cyclinganalytics.com/blog/2018/06/how-does-your-cycling-power-output-compare>





>> <https://www.gribble.org/cycling/power_v_speed.html?units=imperial&rp_wr=199.999&rp_wb=17&rp_a=5.9998&rp_cd=0.63&rp_dtl=2&ep_crr=0.01&ep_rho=0.078035&ep_g=0&ep_headwind=25&p2v=200&v2p=22>
>> 
>> Without a headwind, 8.18 mph requires on 47 watts of power.
>> 
>> 
>
>
>
>
-- 
Jeff Liebermann                 jeffl@cruzio.com
PO Box 272      http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann      AE6KS    831-336-2558