October 22, 2016
You can do a lariat route from the Bayan Zurikh Tovchoo that is about 18 km (11 mi) long. The vertical ascent from the Tovchoo to the turn around point in the forest on the trail is about 300m (1000 feet). So it makes for a nice enough work out. If you are driving, you can safely park your car at the Sansar Supermarket just about 250m after (east) the city gate.
From the supermarket go about 350m east on the main road to a stream/drainage that crosses under the road. Here turn right/south and head towards the mountain on a rough dirt road. Go about 500m south and you will reach a small tunnel to get under the RR tracks.
From the tracks there are multiple ways to get to Chuluut Am. Basically, you just need to head SE. It's 3 km (2mi) to bottom of the valley. Climb up the Chuluut Am until the track becomes very small (6 inches wide) and too difficult to ride. Then turn around and enjoy bombing the DH.
After coming out of Chuluut Am, you want to head west towards the observatory on the dirt road that runs along the base of the mountain. When you get to the observatory road, follow it WNW about 1km all downhill until you cross a little drainage. You are almost due N of the observatory now.
There is a little valley/drainage here that runs north towards the RR tracks and back to the Tovchoo. This little drainage has some fun narrow singletrack. Use the little tunnel to go under the RR tracks and then head NE through the ger district back to the city gate and then on back to the Sansar Supermarket. Do the lariat twice for a solid ride/workout.
There are also a couple of small hills with about 100' climbs and descents that lie between the RR and the road running E and W along the base of the mountain. There is some fun riding on these hills too. So you don't have to take the main dirt road on your way towards the observatory if you don't want.