Calculation of Cycling speed - Example 2

The example taken is a record ride by Iban Mayo, the 10th of June 2004, climbing Mont Ventoux, France.
Stage 4 of that year's Dauphiné Liberé from Bedoin to the top of Mont Ventoux.

It is found that he developped 6,16 W/kg body mass.

To define the grade of the slope, use was made of:

http://www.climbbybike.com/profile/Mont_Ventoux-Bédoin_profile.jpg