Saturday, 6 July—The first stage in the Pyrenees takes the riders from Pau to Pla d’Adet over a 151.9-kilometre route. The finish climb in the mountains above Saint-Lary-Soulan is 10.6 kilometres long and has an average gradient of 7.9%.

It’s an anniversary for Pla d’Adet. The mountain was first included in the Tour de France in 1974, 50 editions ago. That day, Mathieu van der Poel’s granddad, Raymond Poulidor, climbed to triumph on the peak in the Pyrenees. He was succeeded by Joop Zoetemelk (1975), Lucien Van Impe (1976, 1981), Mariano Martinez (1978), Beat Breu (1982) and Zenon Jaskula (1993).

Following a virtually flat first half of the race, the riders will conquer the Col du Tourmalet (19 kilometres at 7.4%) and Hourquette d’Ancizan (8.2 kilometres at 5.1%). At the latter’s summit, there are almost 30 kilometres left.

Following the drop down the Hourquette d’Ancizan and roughly 10 kilometres, the Pla d’Adet appears. The climb serves numerous double-digit digits in the first 7 kilometres before it flattens out for 1 kilometre, after which the rest goes up at almost 9% on average. The Pla d’Adet totals 10.6 kilometres, and the average gradient is 7.9%.

Climbing Defined by the Number

You’re either going up, down or flat when you’re riding.

For every 100 feet, you go forward, you will also travel vertically for a certain number of feet.

You’ve got your grade if you put a percentage sign after that vertical distance.

For example, suppose you go up two feet as you go forward 100 feet. That’s a 2% grade. Suppose you climb eight feet as you go forward 100 feet. That’s an 8% gradient.

If you want to determine the status of climbs by the numbers, we can look at the classification system used in most professional races.  That would mean climbs are classified as 4, 3, 2, 1 (and Hors Categorie or “HC” in the Tour de France.)  This determination is made by a combination of length in kilometres and average gradient, with the position of the climb in the route and the degree of road surface being lesser determinants.  See below:

  • Category 4 – the lowest category, climbs of 200-500 feet (70-150m). Length is usually less than 2 miles (3km)
  • Category 3 – climbs of 500-1600 feet (150-500m), between 2 and 3 miles (3km and 4.5km) in length.
  • Category 2 – climbs of 1600-2700 feet (500-800m), between 3 and 6 miles (4.5km and 10km) in length.
  • Category 1 – climbs of 2700-5000 feet (800-1500m), between 6 and 12 miles (10km and 20km) in length.
  • Hors Category (HC) – the hardest climbs of 5000+ feet (1500m+). Usually more than 12 miles (20km) in length

As for gradients, typically, the average gradient has to be above 4% to classify a climb.  Hors Category (HC) generally climbs on average of>10% or has an extreme length at a slightly lesser grade.

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