Nothing prepares you for the quiet at Paso de Jama. At about 4,200 metres, the border between Argentina and Chile lies on the Altiplano, a huge, high plateau of tawny grass, salt flats and shallow lakes, ringed by volcanoes. The sky is a hard, deep blue, the air is thin and dry, and the only sounds are the wind and the occasional passing truck. Flamingos feed in the pale lagoons, and vicuñas, the delicate wild cousins of the llama, graze beside the road.
The road is the main route between Salta and Jujuy and the Atacama desert, and the ride here is a high-altitude marathon. On the Argentine side, Route 52 climbs from the Salinas Grandes salt flat and the Cuesta de Lipán, a mountain road with dozens of hairpins, to the plateau, and then runs straight and fast across it, before dropping steeply on the Chilean side to San Pedro de Atacama, more than a thousand metres lower. The tarmac is generally good, but wind, ice and snow can close the road at short notice.
Altitude is the real challenge. Sickness can hit anyone, and a bike with a carburettor or an old fuel-injection system may run rough in the thin air, so be prepared. Drink water, move slowly and do not overdo it. The temperature can drop below freezing at night in any month, and the wind is strong and cold in the afternoon. Warm gloves and a windproof layer are essential.
The nearest stations are at Susques on the Argentine side and at San Pedro de Atacama in Chile, roughly three hundred kilometres apart, so fill the tank and carry extra. The border posts have opening hours and paperwork, including vehicle permits, and the process can be long. Do not rush it. Take a hot drink, enjoy the silence and the huge landscape, and plan to arrive in San Pedro by evening, where the nights are cool and the stars are astonishing.