There are two parts to a hill climb, the gradient and the classification. The gradient is the specific angle of the climb at any given part of the climb, which obviously will vary on any climb, The classification is the overall ratting of the climb.
Cyclist often refer the the gradient of a climb in terms of a percentage. The gradient when measured in percentage is just the (vertical climb/horizontal distance) * 100. So you get the idea if I travel 100 m and rise 8 metres that’s 8% gradient. While that may not sound difficult over a longer distance that will really start to bit.
Here’s my spin on the gradients.
At 1-2% you’ll barely notice it, like riding into a bit of a head wind
3-4 % most people will do this quite easily. It rates as hill for a non-rider but to a rider it is a mere bump
5-7% will start to bother non-riders, riders will start to find it interesting
8-9% non-riders will start to look for other ways around
10-15% is going to hurt a non-rider and they may give in, Riders will be challenged by this
15% or greater and you’re in the “praying to your deity of choice” territory. This is going to be tough. Non riders simply will not have enough strength to push themselves up this sort of a climb, Good riders will be challenged by this
As a guide at 10% gradients roads are usually labelled with a warning of steep descent.
Climbs in cycling are rated from Category 1 (hardest) to Category 4 (easiest), based on steepness and length. A climb harder than Category 1 is designated as hors catégorie. Hors catégorie translates as “beyond categorisation”, and signifies an extremely tough climb.
The categories were originally used for mountain roads and the gear needed in a car to pass over them. So, a Cat 1 climb could be passed in a car in first gear, cat 2 in 2nd gear etc. and hors category was impassable by car.
How do the organizers of the Grand Tours evaluate the ratings for the climbs in their races? The Tour organisers use three criteria:
(1) The length and steepness of the climb
(2) The position of the climb in the stage
(3) The quality of the road surface
General guidelines for classification are as follows:
Hors Category (HC) – the hardest, climbs of 1500m+
1st Category – climbs of 1100-1500m
2nd Category – climbs of 600-1100m
3rd Category – climbs of 300-600m
4th Category – the lowest category, 100-300m
There are some exceptions; L’Alpe D’Huez climb is 1200m, but is an Hors Category climb because usually comes at the end of a very tough stage and the climb itself is steep with sections of over 10% grade.
Some of the more popular climbs used in the Tour de France are;
- Col du Tourmalet 2115m
- Col d’Aubisque 1709m
- Col du Galibier 2645m
- Alpe d’Huez 1860m
- Col d’Izoard 2360m
And in case you are wondering what the deal is with the pro’s sticking newspaper up their jerseys when they start the descent from these climbs is. Well, basically it is pretty cold up there on the summits, even if it is summer in Europe. So if you combine the sweat the riders generate from the ascent, the cool temperatures and the wind chill from descending, its make for a pretty cold descend, something that may affect the rider’s health.
So why newspaper instead some fancy new high tech material. Well the tradition of using newspaper dates back to when the tour first started, before all these high tech materials were invented. It was something that easily accessible without having to carry it up the ascent and could then be discarded when they reach the bottom.
As a rule of thumb the temperature drops about 8.5C for every 1,000m ascent. So for the ascent up Col du Galibier that is a potential drop of 20C.