Monday, November 28, 2011

The Switchback

A switchback, also known as a hairpin bend, is a sharp turn on a mountain road. Engineers use switchbacks to give vehicles the ability to ascend and descend a mountain by traversing it, rather than going up or down a prohibitively steep slope. And, constructing a road of switchbacks on either side of a mountain is far more economical than drilling a tunnel.

The 21 switchbacks of Alpe D'Huez.

I found surprisingly little information on the Internet about the history of switchbacks. Some of Europe's mountain passes were cleared thousands of years ago. Great Saint Bernard Pass in Switzerland is the oldest pass in the western Alps, with surviving traces of a Roman road. Today's road may not follow the original road, so I don't know if switchbacks were used by the Romans. However, many Roman roads were built to support military campaigns and transport heavy equipment, so I would suspect that switchbacks were used.

For cyclists, Stelvio Pass and Alpe D'Huez have perhaps the world's most famous switchbacks. Stelvio Pass, located in northern Italy, was built by the Austrian Empire in the 1820s. The northern wall has 48 switchbacks and the southern wall 38. BBC's TopGear rated Stelvio the second best driving road in the world. Alpe D'Huez is a ski station in the French Alps. The Tour de France organizers include Alpe D'Huez in almost every Tour. The road has 21 switchbacks, each one named after a stage winner. 

Switchbacks are most common in Europe, due to the steep gradients. Switchbacks are far less common in other countries. I have seen two in the US (admitedly, I have only been cycling on the east coast). Both were on the southern slopes of Mt Greylock in western Massachusetts. Several passes in Vermont and New Hampshire come close, but I don't think the turns are acute enough to qualify as a switchback.

Real cyclists love switchbacks. On the ascent, the switchback stands as a marker. The signs on each corner of Alpe D'Huez provide a slow (and sometimes demoralizing) count-down, from twenty-one to one. And you get a 180 degree change of scenery.

Descending a series of switchbacks at speed is thrilling. Its also a learned skill. I was a clumsy descender when I began riding in Europe. I would brake all the way through the switchback, and only release once I was on the straight again. Many cyclists would pass me in alpine races. I thought they were just suicidal, but later I read a couple of articles on technical descending. Now, I brake prior to the corner and release as I enter the switchback. I also keep my torso down to lower the center of gravity. By following these steps, the bike accelerates through the corner. You have better control of the bike when it accelerates through the turn. Braking through the corner destabilizes the bike.

It took some practice, but now there is nothing I enjoy more than effortlessly gliding down a series of tight European switchbacks at high speed.

A switchback on Stelvio Pass.

A sign indicating 40 switchbacks remain until the summit of Stelvio Pass.

A Swiss switchback on Umbrail Pass.

1 comment:

  1. ...and hence, "SWITCHBACK Publications". Keep the adventure articles coming!