On Wednesday, August 14, 2019 at 1:33:35 AM UTC-7, James wrote:
On 14/8/19 1:22 pm, Claus Aßmann wrote:
Tom Kunich wrote:

That means that the lead rider is making about 426 watts and there is a rotation of only 8 riders so you don't
have that much time off of the front.

Let's assume there are really only 8 riders in the front for 2
hours. So 1/8th of the time the rider produces 426W (as you
calculated) and 7/8th of the time he drafts which means about 30%
less effort, i.e., about 300W.
Now do the math and you see that the average is way below 400W.

The hour record requires about 440-460W for one hour -- if you
think any pro cyclist can hold 400W for two hours then please
post _real_ data, not your guesstimates...

Here's one example:
In the 2015 Tour De France won by Chris Froome. He made his mark
on Stage 10 during the the climb to La-Pierre-Saint-Martin, where
Froome took the lead "It's about a 15.3 km climb," said Kerrison.
"Around 41.30 mins. Chris's average for the whole climb was 414w,
and a VAM of 1602 Vm/h."



The UCI or Olympic 100km mens team time trial, the average speed is
approximately 50km/h, so 2 hours with 4 fresh riders, not fatigued by
weeks of racing a grand tour.

bikecalculator.com suggests the power required is 430 W using aero bars
and tubulars.

1/4 of the time a rider must produce 430 W, and 300 W for 3/4 of the time..

I think the average is just over 330 W.

The courses are generally relatively flat, so slightly heavier and more
powerful riders are chosen to compete. Less reliance on power to weight
ratio.

The UCI individual time trial requires an effort of about 50km/h for up
to an hour, so 430 W continuous for 1 hour, similar to the hour record.

--
JS

I would have to do some calculations on that since time trial bikes have significantly less resistance and hence require less power to carry speed.

Never the less, you get a fairly accurate picture of power output with weight, frontal area (including estimated drag factor) and time over distance. The accuracy of this rivals a power meter.

As I pointed out, there really is no use for a power meter on a sports bike other than to brag about your power output. Chris Froome has already stated that he uses if to keep his own power output within his physical limits and not to measure top power output.