Local hills vs TDF climbs

Note: This piece was originally published in the newsletter of the Smoky Mountain Wheelmen. Their archives no longer seem to be accessible, so I am reproducing it here as I originally wrote it.

Have you ever wondered how the hills you ride compare to those in the Tour de France?   Watching the Tour on television go me thinking about this question, and the Tour’s system of categorizing climbs could provide some basis of comparison.

Over the years, I have heard it said many times that the difficulty of climbs in the US just doesn’t compare to those in Europe.  US infrastructure is newer and designed for keeping cars and trucks moving at the speed limit, and allowing travel in bad weather including ice and snow.  In contrast, European roads evolved from trails.  Furthermore, with the higher population density, it may be necessary to connect centers of population through terrain that could be avoided in the US.  Most of the people I have heard this from have had a western US perspective.  I am not so sure that it is true in the East.  Mountain passes are not as high, but slopes are frequently steeper, and the road infrastructure is often older than in the West.

Climbs in the Tour are divided into five categories.  Categories 1 through 4 (category 1 is the most difficult) plus the paradoxically-named category referred to as Beyond Category (“hors catégorie”), which is more difficult than category 1.

The primary purpose of categorizing climbs in the Tour is to assign points in the King of the Mountain competition, with more points awarded for climbs in more difficult categories.   Categorizing climbs also presumably provides the teams competing in the Tour important information to help develop their day-to-day race strategies, and it gives fans a way to set expectations about the kind of action that will take place in a stage, and a way to compare the level of difficulty of different stages.

The primary criteria used to determine the categories for the TDF are average steepness (expressed in percent) and total length of the climb.  A secondary factor is the location of the climb within the stage.  The categorization process is reportedly subjective, and other factors, such as maximum slope and road surface, may factor in. 

For my analysis, I copied the slope and length of climb information from the TDF website for all the categorized climbs in the 2005 Tour and put this information on a graph.  The only information I used is average slope and length of climb.  This limited amount of information seems to explain most of the variation, with each category grouping together, though category 3 and 4 climbs do seem to overlap some.

I used computer maps and GIS software, information from web sites, and a few on-the-ground measurements to pull together slope and length information from some regional climbs.  I then used this information to place climbs on the graph and decide which line or points it is closest to.  My methods are not very exact, but they are close enough to provide a valid comparison.

Here in the southern Appalachians, a 6% climb is routine, but many of the climbs that we struggle up are not long enough to make the category 4 cutoff (for convenience, let’s call it 0.6 miles).  French Road between Kimberlin Heights and Governor John Sevier Parkway is plenty steep at about 6.6%, but not quite long enough.  The climb on Ray Gap Road from Union Valley averages about 9.6%, but is only 0.4 miles long.  I can’t say for sure that a climb like this would not be included as a category 4, but there was nothing this short that was rated this year.


But you don’t have to look too far to find climbs that would rate as 4’s.  Neubert Springs Road over Brown Mountain (between Colonial Village and Tipton Station Road) is about 0.8 mile at 5.3%.  Martin Mill Pike over Red Mountain (north from Tarklin Road) is about 1.1 miles at 3.9%.  Big Ridge in Anderson County is 1 mile at 6.2% (maybe even a category 3).

Comparing some of our bigger regional climbs to the Tour rating system is interesting, but not necessarily straightforward.  Riding the Foothills Parkway up to Look Rock from the highway 321 (Townsend) side, the climb is interrupted by a downhill section about 1.4 miles long.  The first portion of the climb before the downhill section is 3 miles at 6.1%, and would rate as a tough category 3, similar to a couple of TDF climbs.  The second segment of the climb is longer (4.9 miles), but in spite of long section of 6%, it averages out at 3.5%, and would rate as a long category 4.  Considering this entire section of road as one climb (9.1 miles at 3.4%) would probably put it in category 3 because of the length.

There is another way up Chilhowee Mountain near Look Rock, with the ironic name of Happy Valley Road.  At 1.9 miles and 10.1%, it would rate as a category 2, and matches the steepest, shortest category 2 climb in this year’s Tour (Côte de la Croix Neuve, also known as montée Laurent Jalabert).

Some of our regional century rides seek out hard climbs to make them more challenging.  The Three State Three Mountain ride out of Chattanooga, as its name suggests, has three significant climbs.  Suck Creek (Signal Mountain/Walden Ridge) (5.6 miles at 4.8%) is closest to the category 2 line; Sand Mountain (2.9 miles at 5.7%) looks like a category 3; and Lookout Mountain (2.5 miles at 8.7%) is a solid category 2.  Pitts Gap on the Sequatchie century (3.6 miles at 6.4%) is closest to the category 2 line, but is similar to two category 3 climbs.

The Mount Mitchell climb, at 20 miles, is longer than any in the Tour this year, but the slope (4.5%) is relatively gentle for the big climbs.  It is not obvious where this would fall in the Tour system, but is closer to the category 1 line than to the category 2 line, at least the way I have done the analysis. Newfound Gap (12.8 miles at 5.1%) might be a little easier, but not much, at least by this measure; it is also closest to the category 1 line.

The Cherohala century has two notable climbs.  First is the two-headed climb up The Dragon.  The first head is Shaw Grave Gap (4.3 miles at 4%), which plots right on the category 3 line.  Deals Gap is 3.7 miles at 3%, and a long category 4.  The climb up the Cherohala Skyway from where the road leaves the Santeetlah River near Rattler Ford to the top of Art Stewart Ridge is 6.4 miles at a slope of 9.1%.  This is as long as the shortest Beyond Category climb in this year’s Tour (Plat d’Adet), and significantly steeper.

There are three ways to climb Grandfather Mountain.  I would call two of them category 2 climbs (2.2 miles at 7.8%, and 8.4 miles at 5%). The third, 6.5 miles at 6.7%, is a category 1, plotting between La Ballon d’Alsace and the Col du Télégraphe.  Another category 1 climb is Hogpen Gap in north Georgia (7 miles at 7%).

This discussion might give the reader who has ridden some of these climbs a better idea of what the Tour riders are going through and the climbing riches of our region.  Generally, the Ridge and Valley and Cumberland Plateau areas have plentiful category 4 and 3 climbs with a few category 2’s, though they generally run out of mountain before attaining category 1 status.  The category 1 climbs are mostly confined to the Blue Ridge, the tall spine of the Appalachians.  Even there, there are not many honest Beyond Category climbs, and the Cherohala may be the only century around that contains one.


  Typical short/steep climb Typical long climb Number in 2005 Tour
Category 4 0.6 mile @ 5.2% 6 miles @ 2.9 % 25
Category 3 1.0 mile @ 7.3% 7 miles @ 2.9% 18
Category 2 1.9 mile @ 10.1% 13.5 miles @ 3.5% 7
Category 1 4 mile @ 8.3 14 miles @ 6% 10
Beyond category 6.5 miles at 8.5% 16 miles @ 6.1% 5

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  1. #1 by RidinWind on November 15, 2010 - 10:24 am

    Sounds like some great riding!

  2. #2 by Brad Shaffer on July 17, 2011 - 7:05 pm

    This is fantastic information. Hey, how would you categorize the 12 mile section of NC 181 in the Blue Ridge to Bridge to Bridge race? Thanks!

    • #3 by valvejob on August 14, 2011 - 4:49 pm

      Sorry for the slow response — I kept meaning to research the B2B route. I have not ridden B2B, so I am not familiar with it. Are you talking about the section of NC 181 from Brown Mountain Beach Rd to the top of the ridge, maybe where it crosses the Blue Ridge Parkway? The route description is posted is not very specific about route details — no map yet this year. If that is the segment you are interested in, I will do the analysis when I get a chance.

      • #4 by valvejob on August 15, 2011 - 8:48 pm

        Without studying the topography too closely, it looks like NC181 climbs from 1100 ft elevation at Smyrna Church/intersection with Brown Mtn Beach Rd to 3800 ft at Jonas Ridge (elevations and place names from topo maps). Distance (from google maps) between these two points is 13 miles, so average slope is 3.9%. By the above calculations, that looks like a typical long category 2; it plots just above the 2 line, but a long way from the category 1 line.

  3. #5 by Graham Pring on May 13, 2012 - 8:19 pm

    Fabulous effort.
    I have been trying to work out how the Bryton website classifies the input from their devices into the levels.
    Your site has given me a great starting point.
    I have ridden a 10% gradient which is 2 km long four times and Bryton have given me a HC category, while three times is a Level 1 category, so your original graph line for HC is probably correct. (5 miles X 10% and 3.75 miles X 10%).
    Thanks again. Graham Pring – Adelaide, South Australia.

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