"With an average steepness of 12% and pitches of up to 30%, this 2.1-mile screaming downhill stretch of the overall loop is definitely not for beginners. Repack is a rocky, loose and often dusty narrow dirt road marked by rain ruts. The rest of the loop around Pine Mountain is not as technical though there are some advanced technical sections of brief duration. So what? Walking up or down them is always an acceptable technique, which means even strong adventurous beginners can ride most of this loop. Throughout the entire loop, the terrain climbs steeply up and down, gaining and losing about 1,600 feet. Lying in the Marin Municipal Water District (MMWD) and Marin County Open Space, the route leads you up and down several ridges, through many different ecosystems, and offers a splendid view of the northern San Francisco Bay and beyond. Plenty of downhill stretches over remote terrain, especially the area around the secluded backside of Pine Mountain, make the huffing and puffing up the steep sections worth it."