The San Gabriel Mountains feature many picturesque and challenging climbs. Glendora Mountain Road (GMR to locals) ranks among the most popular climbs in Southern California. GMR poses a steady pitch between 4.5 - 5.5 percent. GMR confronts racers with a dizzying number of corners, as it twists and turns up the mountainside. Historically the time trial used the full 8 miles of GMR. A road closure, however, forced the reduction to a 3.7-mile stretch of it. That once necessary reduction remains unchanged since the race director and teams noted that it makes for a more competitive race.