The Klausen Pass was built for horse-drawn coaches in the 1890s, and a generation later it was being used for motor racing. Between 1922 and 1934, the Klausenrennen, a hillclimb from Linthal to the summit, was one of the great events of European motor sport, with drivers such as Rudolf Caracciola and Hans Stuck throwing huge cars up the hairpins at average speeds that the road had never been designed for. The race was dropped in the 1930s, but the road has never quite lost the association, and on a quiet morning you can imagine the noise.
The pass, at 1,948 metres, links the canton of Uri with Glarus and is open from about June to October. It is a proper alpine road, with long, sweeping stretches, tight hairpins and views of high peaks, glaciers and waterfalls. From the Uri side, the climb begins in the Schächental, a green valley with farms, and rises through forest and meadow to a series of bends cut into the rock, then to the broad saddle at the top, where a restaurant and a small chapel stand. The surface is smooth and the gradient is moderate, so the road is a pleasure for all kinds of riders.
The geology is striking. The peaks around the pass are folded and tilted limestone and shale, and the Glarus Alps just to the east are famous among geologists for a great thrust fault where older rock lies on top of younger, now part of a World Heritage area. The landscape tells the story of the Alps' formation, though most riders are more interested in the next bend.
Cows are a feature of the pass in summer, and you may find yourself sharing the road with a herd, their bells clanging, calves and all. They have right of way in practice, and you wait, engine off, until they pass. Dairy farmers make cheese in the huts along the route, and the famous Schächentaler cheese can be bought at roadside stalls. Weather at the top is changeable, with cold wind, cloud and rain common, so a waterproof layer is wise.
Altdorf, about fourteen kilometres from the Uri side, is the nearest large town, and Linthal on the Glarus side has services. Fill the tank in Altdorf, and bring cash for the cheese stalls. A hot meal at the summit restaurant, with a view of the Clariden range, makes the climb feel earned.