Tour 639 leads up to the Karröster Alm hut (1,467m) on the west-facing slopes of the Tschirgant mountain. The ride up to through the Tschirgantwald forest is possible from May until October and takes around one and a half hours. The hut is the ideal place for a drink and a snack, while those interested in geology and the history of the region should visit the Geological Trail in Karrösten.
- The car park in Karrösten is also the starting point for the Geological Trail with information boards telling visitors about life in the Tethys Ocean and how the Limestone Alps were formed.
- Mining has existed in the region around Karrösten since the Bronze Age and reached its height in the 16th century. Riders will see access points to abandoned mines and piles of waste rock along the sides of the trail.
- Cyclists can enjoy fantastic views of the Upper Inntal Valley, including the town of Imst and the region around the Muttekopf mountain as well as into the Gurgltal Valley and up to the peak of the Tschirgant mountain.