Alpe d’Huze

Overview

The Alpe d’Huze is known because of its use in the Tour de France, though 2018 will be its return after an absence of several years. Despite its legendary status, this ride is only rated by ClimbByBike as 803 in the world, 152 in France, and 288 in the Alps. It includes 21 hairpin turns, but its length and elevation gain are relatively speaking steady but not challenging for elite cyclists.

Its status is because of its position within a stage. It is a climb to a ski resort and so the stage finishes at the summit. . In the 2018 Tour de France, it is proceeded by two higher climbs and the climb begun 100 miles into the stage.

Mountain Summary

This climb has a cycling distance of 13.2 km and an average grade of 8.1% with a maximum grade of 10.6%. It begins at 744 m and ends at 1815 m with an elevation gain of 1071 m.  At 3514 ft, the effects of altitude are minimal.

Mountain Profile

As climbs go, this has a short 2 km initial climb around 10% and then proceeds for most of the way at a steady climb around its average.

https://www.climbbybike.com/profile.asp?Climbprofile=Alpe-dHuez&MountainID=5

Required Climbing Effort

Using our formulas for Effort Against Gravity and Effort Against  Rolling Resistance, and ignoring aerodynamic drag because of slow speed and the many changes of direction, we compute the total work for a range of cyclist’s weights on a 16 lb cycle as follows:

Cyclist-Cycle Weight Work Against Total Work
Cyclist(lbs) Cycle(lbs) Newtons Gravity RR Joules
125 16 627.20 671,730.40 16,558.06 688,288.46
150 16 738.40 790,831.53 19,493.89 810,325.42
175 16 849.61 909,932.66 22,429.71 932,362.38
200 16 960.82 1,029,033.80 25,365.54 1,054,399.34

Climbing Power Levels

We connect the Total Work to the Cyclist by asking what power level must they train to make the climb in a certain time.  First, we estimate Marco Pantini’s level in his 37 min 35 sec ascent. Assuming he corresponds to the first row, we divide by the time in secs and get 305.23 Joules/Sec or 305.23 Watts. Converting using his mass of 57.5 kgs, yields 5.31 watts/kg⋅sec. This would be equivalent to powering three 65 inch LED TVs.

For a 175 lb recreational cyclist looking to make the climb in 90 minutes, they would need 172.82 Watts.  Again converting to Coggin’s yields 2.18 watts/kg⋅sec. In general, I prefer the first term as it tells you most directly the number of watts a given cyclist would need to produce.

Computing Difficulty Indexes

Plugging the numbers into a spreadsheet, we get

ClimbByBike Index = 124.4743

Codifava Index = 123.38

Given the first index includes a factor for Riding at Altitude which in this case is 8.15 points,we should adjust the second to

Codifava Index = 131.53

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