The year round great weather in the San Francisco and Silicon Valley
area has made bicycling popular for 30 years or more. In recent years,
increasing traffic, big SUVs, and cell phones have encouraged many bicyclists
to try traffic free mountain biking. After 20+ years of regular road cycling,
I took up mountain biking a couple of years ago. There are other web sites
that describe Silicon Valley area mountain bike routes, but most of those
routes are for intermediate and advanced riders and the routes may be too
technically difficult (lots of rocks and roots) for beginning riders.
This web site describes some routes that I found interesting when I first started mountain biking. All the routes start near Skyline Blvd., about 30-40 minutes from Stanford University. Many of the trails are over 2000 feet in elevation and give you a nice variety of terrain and scenery. The routes are suitable for moderately fit road cyclists with beginner to intermediate technical mountain bike riding skills. The trails are mostly hard packed dirt and the rocky sections are generally short so, if you need to, you can walk through them pretty quickly. The first route is the easiest and shortest. The last route is more technically and physically challenging. If you can get past all four of these, you should be ready for the more technical routes around Skeggs Point or Santa Cruz.
The photo above is from Borel Hill, which sits over 2500 feet above Palo Alto and Stanford University. The first two routes described below include Borel Hill.
Here is some general route and safety information
Please send me your comments on these routes!
The MROSD web site also lists current trail conditions and regulations. Some trails, especially in Monte Bello and Long Ridge preserves, can be closed by muddy conditions during the winter rain season. Some important regulations include: a 15 mph speed limit (5 mph when passing), helmets are required for all bicyclists, and all trails are closed 30 minutes after sunset. When passing horses, you should generally get off your bicycle and let the horse pass you. Trail access is mostly a political issue (not environmental or safety) and horse owners are very politically powerful, so you don't want to annoy them.
All of the routes described here do have significant hills. Road cyclists who can bicycle up Old La Honda Road (a 3 mile, 1500 foot climb from Portola Valley to Skyline) shouldn't have any trouble with the first three routes; the fourth route is somewhat more strenuous. If you're interested in less hilly routes in the Palo Alto area, there is a flat dirt levy trail along the Palo Alto Baylands down to Mountain View Shoreline Park. There are also some easy rolling trails Palo Alto's Arastradero Preserve. Some portions of the routes I describe are easier than others. In particular, Russian Ridge and Long Ridge preserves have several easier trails.
Of course, all outdoor activities are potentially dangerous. The ROMP web site has a beginner's guide that discusses trail etiquette, safety, and riding technique. I do recommend that beginners always ride in groups, preferably with at least one experienced rider, at least until they are very comfortable with their skills, trails, and equipment. If you're interested in group mountain bike rides in this area, the MROSD does lead them periodically (mostly in the spring and fall, check the MROSD web site). The ROMP bicycle club also leads many mountain bike rides in the area.
None of the MROSD preserves have drinking water, so bring plenty of your own. Those 100 ounce Camelbak hydration systems work real well. Dehydration can be a serious problem during the hot summer months. High calorie snacks (fruit, bread, energy bars) are also a good idea. A mechanical problem can make your ride longer than you planned, so extra food and water is a good idea.
While all of these routes are short enough that you can walk out after a mechanical break down, being able to fix it and ride out is a lot more fun, especially late in the day. I always bring the tools (and knowledge) to repair common problems like flat tires, broken chains, bent spokes, and bent derailleurs. You may be able to borrow tools from a passing cyclist on summer weekends, but off-season and on weekdays, you may not see anyone else all day. Also, cell phones do not work on many (or most) trails.
There are many wild animals in the Santa Cruz mountains, including wild pigs, mountain lions, rattle snakes, and coyotes. I've never heard of any of these attacking a bicyclist, though you should take basic precautions like not stepping on snakes and not getting between baby animals and their parents. Poison oak is a more important problem for trail users; learn to recognize it and avoid it. Ticks can carry Lyme disease, so check for them on your skin after every ride. Auto traffic can be very dangerous. All these routes cross Skyline Blvd. at least 2 times each. Especially on weekends, sports cars regularly exceed the 50 mph speed limit and motorcycles have been known to double the speed limit. When crossing the street, if there is a bend in the road, listen for vehicles and look again when you're half way across. If you have a medical emergency, call 911, not the MROSD.
Weather along Skyline Blvd. can be difficult to predict. Some times, Palo Alto can be warm and sunny, but the coastal fog makes Skyline cool and damp. Other times, the fog burns off along Skyline by 10 am, while fog from the bay keeps Palo Alto overcast all day. If you're driving to the trail head, I would recommend bringing arm and knee/leg warmers and a vest/jacket with you in your car, just in case. On a longer ride, you may want to carry some of that stuff with you in case the fog reappears in the late afternoon. Fortunately, rain storms are pretty much limited to winter and mostly accurately forecasted. Snow is rare, but it can happen.
Most trail junctions are signed. Some signs have a blue graphic, indicating the Bay Area Ridge Trail (usually just called the Ridge trail). You should always check your map in addition to written directions. Do not ride on trails marked "no bicycles", either on trail signs or on the trail map.
Check out my Silicon Valley road bike routes.