Originally Posted by billridesbikes

The average power argument doesn’t always hold because generally you’re capable of higher output over less time duration but power drops off for longer times. But if we did use 308w for both segments the combined time comes to 26:11 in this example, still much slower than the last split example. The reason is that for power vs. speed the speed drops off faster as a percent on a grade than on a flat road. In this example 300w=>270w reduces your speed by 4% on a flat road but by 9% on a 6.3% grade.

But we are talking about the same apples here. Pick a target power, go about 90% of that on the flat and then give it all you got for the next 15-16minutes up the hill, this will produce the best time for whatever condition you find yourself in at that time of the day.

If the duration was longer you wouldn’t change the spread for power but instead you would lower your target power inline with that duration, this is what would give you the best time.