Sun Valley, ID. Western Spirit Cycling has partnered with Sun Valley to provide a summer solstice Outerbike in one of the bucket list locations of mountain biking. With over 400 miles of singletrack spread throughout the valley, the mountain biking is some of the best—and most scenic—in the country. Bald Mountain now boasts America’s longest purpose-built downhill and 3,100 feet of thrilling lift-accessed trails (including two new downhill rides!).