Mountain biking to the top of Mount Tamalpais is always a satisfying ride. Whether you spin up the gradual Railroad Grade from Mill Valley or take the more challenging Eldridge Grade from Phoenix Lake in Ross, arriving at the top and soaking in the views makes you feel like you conquered a mountain.
In this edition of we will ascend Tam on one of my favorite trails, Eldridge Grade, and mix up the return with a detour to quaint Potrero Meadows and beautiful Lake Lagunitas. The total loop from Ross is slightly over 15 miles and the terrain is friendly fire-roads with the exception of the loose rocks at the top of Eldridge.
Right out of downtown Ross Lagunitas Road leads to Natalie Coffin Greene Park. Cross the bridge at the parking lot and climb to Phoenix Lake. After a quick meander around the lake you will see a signed intersection and the left turn up Eldridge Grade.
Eldridge Grade is a fantastic fire-road that delivers a manageable, consistent pitch up Tam and a more rugged challenge than Old Railroad Grade. The start of Eldridge always makes me second guess my fitness as it features a brief steep section. Have no fear since you will soon settle into a rhythm that makes the remainder of the climb more merciful. At the first intersection veer left and after that it is nearly impossible to get lost, just keep going up. As the wheels turn redwoods offer shade and clearings offer grand views. As you approach the summit the trail gets progressively rockier. Spinning an easy gear and running low tire pressure will help with the rocks, just be careful not to go too low on the PSI or a sharp edged rock may "pinch-flat" the tube (the minimum listed tire pressure on your tire is a good guess). Just when the rocky trail is about to defeat your willpower you reach the smooth pavement of Ridgecrest Blvd near the summit, huzzah!
At the road it is time to decide whether you want to visit the East Peak or continue with the loop. I like to cross the road and spin up the short paved path to the East Peak summit of Mount Tamalpais. Sitting at the peak offers stunning vistas, a chance to refill on water, and the satisfaction of conquering the mountain's top. After recouping it is time to backtrack down to Ridgecrest Blvd and spin up the short and gentle hill towards the West Peak (elevation 2,500 ft). With the wind in your hair you descend from West Peak, keeping an eye out for a fire-road on your right named Rock Springs- Lagunitas Road. If you reach the Mountain Theater you have gone a tad too far.
Rock Springs- Lagunitas Road climbs briefly before dropping to Potrero Meadows. The meadow is not grand or extravagant but instead so serene and inviting that it almost feels forgotten. From here you stay right all the way down Rock Springs- Lagunitas which may have a sign indicating maintenance, though the dirt road does remain open. The hard earned altitude drops away quickly and soon you approach Lake Lagunitas. Take the right turn at the lake to go the long way around in order to enjoy the fun trail and gorgeous views of the lake.
From the Lake Lagunitas parking lot follow the paved road for a minute to a right turn at the large gate. Beyond the gate the paved road drops to a left at Fish Gulch (near a water pipe) where your tires meet dirt again. All too soon the signed intersection where you originally picked up Eldridge Grade appears and you continue straight back to Phoenix Lake.
Spinning back home magnificent images from the top of Tam and calming pictures from Potrero Meadows replay in your head. Your legs salute you for putting them to good use and you bike would be wagging it's tail if it had one. Nicely done, you've conquered Tam the hard way.