Kandovan Pass is the high point of the Chalus Road, a saddle in the Alborz mountains at about 2,700 metres where the road crosses the watershed between the dry plateau of the Iranian interior and the damp forests that face the Caspian Sea. This is not the Kandovan of the famous rock-cut cave houses in the north-west, which is a different place entirely. Here the name belongs to a pass and a tunnel, and the importance is in what happens on either side.
The south side is open and sparse, with grey slopes and sheep tracks, and the road climbs in bends from the Karaj valley. The north side is a different world, with the cloud pouring over the crest and falling into green forest. A tunnel carries the main road through the ridge, and the old pass road, which twists over the top, is a rewarding diversion for those who want a slower and more scenic route if it is open. The contrast between the dry and the wet is one of the great experiences of riding in this country, and it can happen within a few minutes.
Weather deserves respect. Fog is common on the northern side, snow can arrive early and stay late, and the road can be icy between autumn and spring. In summer, the pass is often a relief from the heat of the plateau, and cloud rolling in from the Caspian lets you feel the temperature drop. Gusts, rain and sudden fog are all normal. Watch for trucks which grind up and then come down fast with hot brakes, particularly on the descent.
Traffic also varies. During holidays and weekends, thousands of cars come this way, and the queues at the tunnel can be long. If you can, choose a weekday for the crossing.
Fill in Karaj before leaving, and plan to refuel again on the Caspian side, in Chalus or the towns along the coast. At the top and in the villages, you can usually find tea, bread, and simple food from roadside stalls, but the choices thin out as you climb, so do not rely on them.
Once through, the descent through beech forest towards Chalus is a pleasure, with long bends, damp air and the smell of leaves, and the Caspian waiting at the bottom.