The route leaves Navas del Rey and follows the M-501 beside the San Juan reservoir, on the river Alberche, passing Pelayos de la Presa to San Martín de Valdeiglesias. From there it continues on the M-542 to Cadalso de los Vidrios, with a stretch of the M-541.
It crosses the municipalities of Navas del Rey, Pelayos de la Presa, San Martín de Valdeiglesias and Cadalso de los Vidrios. It is not a road with many bends: its appeal is the water of the reservoir, the pine woods and, further on, the vineyards and countryside of the Sierra Oeste. It is a classic weekend ride for Madrid motorcyclists.
It is about 34 km and almost an hour without stops, with few real bends (around 26) and one hairpin. Altitude ranges from about 520 m to 818 m. At weekends there is heavy traffic of cars, motorbikes and cyclists, with people pulling in and out of the reservoir areas: overtake only where it is allowed and with clear visibility, and do not get drawn into other people's pace.