The Coll de l'Obac is a beautiful climb that connects the city of Terrassa with Castellbell and Vilar, very close to Monistrol de Montserrat, at the foot of the mountain. It is one of the 3 alternatives to reach the foot of Montserrat from Vallès Occidental, in addition to Vacarisses and the main road that takes us from Martorell and Olesa de Montserrat.
It is a port that has 4 aspects:
- South slope, which starts from Terrassa. It is a long and difficult climb, especially in its initial part, getting tougher in the last 4 - 5 km, without ever exceeding 6 - 7%. Very twisted road, without shoulder, with rough asphalt and with a lot of motorcycle and car traffic (as well as cyclists) during the weekend and holidays. We must be careful. It is a mostly shady road.
- Southwestern slope (BV-1211 road), which crosses the town of Vacarisses and deviates to the left through the "Els Caus" urbanization. The initial part is very laid out; However, the section that crosses the "Els Caus" urbanization has very hard ramps, with the road narrow and concreted in some sections.
- North Slope, which starts from Castellbell and Vilar. It is a climb very similar to the South slope due to its length and type of port. It differs from the previous one in that it has a considerable ramp when crossing the town of Rellinars and the road has hardly any shadows.
- Northwest Slope (BV-1212 road), which starts from the C-58 road, goes up to the town of Vacarisses and takes the section to the right of the "Els Caus" urbanization, previously described. The first stretch to Vacarisses is straight and very beautiful, with a very quiet and winding road, paved to perfection.