Too Ashuu is the point on the main road south from Bishkek where the country changes character. North of the pass, the highway crosses the Chuy plain with its fields, towns and traffic. South of it, you drop into a high, empty world of grass, yurts and sheep, the Suusamyr valley, with the Ala-Too wall rolling on in every direction. The pass lies at about 3,500 metres on the Kyrgyz Ala-Too, and the road across it is the central artery of the north-south link that joins Bishkek to Osh, built in the Soviet period when nobody was counting the cost.
The climb from the north is long and spectacular. The road hauls itself up a narrow gorge, climbing through a flight of hairpins that clings to the valley side, with trucks grinding along ahead and a river thundering below. A tunnel, built in the 1950s and a little over two kilometres long, carries the road through the crest and is notorious for its poor lighting, fumes, wet surface and the way oncoming drivers use the middle. Take it slowly, keep your visor clear, and be prepared to be seen. On the far side the road emerges into daylight, the valley widens, and the air is thin and cold.
Weather here is a character in its own right. Snow can fall in any month, fog can close the gorge in minutes, and wind funnels through the tunnel portals. In winter avalanches and ice make the pass a serious proposition. The best riding window is mid-summer to early autumn, early in the day, when the trucks are fewer and the sky is clear. A jacket for the south side is not optional, even if it is hot in Bishkek.
Fuel is an important detail. There is little on the climb itself, so refill before you go, at Sosnovka or farther back on the plain, and again when you drop to the Suusamyr side. Small roadside cafes sell tea, bread and plov, and you will find stalls offering kymyz, fermented mare's milk, a drink that tastes much worse than it sounds good. Stop at the top for a photograph, check your tyre pressures and layers, then ride on: ahead lies one of Central Asia's best long days.