Distance: 24.4 miles out and back
Elevation gain: 3580 ft
(A Best of the Best ride)
Mt. Diablo is another of the three iconic Bay Area climbs. It’s less tranquil than Mt. Hamilton and less scenic than Mt. Tam, but it’s grand nonetheless. No other ride gives you such a distinct sense of “climbing a mountain.” It’s a long climb but never brutal until the last 100 yards. It’s an iconic ride, and there isn’t a serious cyclist in the Bay Area who hasn’t done it, many times. The view from the top is a tourist attraction, and for good reason—they say on a clear day a person looking north and east can see further than from any other spot on the planet except Kilimanjaro. OK, that turns out to be a myth perpetrated by real estate developers—it’s not even the biggest view in California, Mt. Whitney’s being much larger—but you can see bits of 40 of the 58 California counties, you can see the mountains around Lake Tahoe, and you can see rock formations in Yosemite. That’s pretty cool.
That being said, it’s not a ride I do for the scenery, though some love it. The foliage is standard East Bay hill shrub and grass, and the vistas, while large, are mostly of East Bay urban sprawl. There are nice wildflower blooms in season.
The ride is approachable from the north, via North Gate Rd., or the south, via South Gate Rd., and they’re both supposed to be good routes—the north route being steeper and shadier—but the south route is the preferred one and it’s the only one I’ve ever done, both ascending and descending. The first half of the descent (from the summit to the Ranger Station) is as good as anything you’ll ever do—if you manage the traffic.
Mt. Diablo, as much as any ride in Bestrides, is affected by traffic. Diablo is a magnet for tourists, hikers, mountain bikers, and rock climbers—and their cars. On summer weekends, the place is a zoo. If you were ever going to get up early and be on the bike by 7 am (or call in sick and ride on a weekday), this is the time. In the early morning it’s like the road is closed to cars…and in fact it may well be, since there’s a gate across the road that’s typically closed at night (the park “opens” at 8 am). Riding this ride with no or very few cars triples the pleasure, and changes the descent from good to grand. Despite the crush, the hill is very bike-friendly—there are signs at most blind curves reading “Do not pass bikes on blind curves,” for instance.
There is also the weather to consider. The summit can be foggy, windy, and cold even when the weather at the base is benign. The last time I rode Diablo, it was sunny, still, and 67 degrees at the bottom and 47 degrees, with a blasting wind and freezing white-out fog, at the top. I took more clothes than I thought I’d need, and still froze. This doesn’t mean you shouldn’t ride in such conditions—cold and fog keep the car tourists and hikers away, so on that 47-degree day I never saw a car in my lane during the entire descent.
(To see an interactive version of the map/elevation profile, click on the ride name, upper left, wait for the new map to load, then click on the “full screen” icon, upper right.)
You can get to the bottom of the mountain in many ways. If you drive to the base of the hill, there is a fair amount of grassy shoulder parking along Mt. Diablo Scenic Boulevard, with signs inviting you to use it, but I’d imagine all the spaces would be taken on an ordinary weekend morning. One way is to ride BART to Dublin if you want to get in around 10 miles of mostly flat, quiet grassland riding before starting to climb. Another is to BART to Walnut Creek, ride south on the main street until you can cross under Hwy 680 to Danville Blvd. paralleling 680, and ride Danville Blvd., a popular cycling route on a very pleasant though trafficked residential road with a big bike lane. Go L onto Stone Valley Rd., R on Green Valley Rd., L. on Diablo Rd., and L. onto South Gate Rd. (this road is confusingly signed “Mt. Diablo Scenic Blvd” for its first half mile—don’t let it throw you). This will give you some flats and some mild climbing before you get to the hill. There is traffic all along this route, but there’s good bike lane shoulder all the way to Diablo Rd. Diablo Rd. is narrow with no shoulder, but for the first half of it there’s a nice separated bike path up the left side of the road. After it ends, it’s a short white-knuckle ride with cars whizzing by your shoulder to the turn-off. This leg is marked as a bicycle boulevard (with big white bicycle icons painted in the middle of the lanes), so the cars theoretically know you have a right to be there. I typically park off Danville Blvd. and ride from there, which gives you about 30 minutes of mild climbing for warm-up. Perhaps the shortest, easiest, and flattest approach if you’re driving is to park at Diablo Vista Park about 4 miles to the east of the beginning of the climb, as several readers suggest below.
When you start up Mt. Diablo Scenic Blvd, you’ll be sure you’re on the wrong road. You’re riding past schools and houses in what feels like a suburban cul-de-sac. Fear not—all will be well. Right before the first major dip, notice the faded message written on the road: “Danger severe road damage ahead.” It’s a reminder that there used to be a 1/4 mile stretch of incredibly awful road surface following, but it’s been freshly paved and is now glassy. As you cross it, say a prayer for the intrepid pioneers who came before you.
The climb is actually two climbs, the road up South Gate Rd. to the Ranger Station at the junction with Summit Rd., and Summit Rd. itself. The first is a fairly easy climb, 4-6%, with lots of variety in the road contour, so you don’t get bored, and a delicious rolling flat through pretty oaks in the middle. Just before that flat you get to the State Park Entrance, where there’s a kiosk that takes money from cars. I don’t actually know if bikes are supposed to pay or not (the sign says “ALL vehicles” are supposed to pay), but I’ve never paid and never been asked to. Ten yards past the kiosk on the R is a water fountain. Just before you encounter the kiosk is perhaps the best vista on the entire ride on your R.
At the Ranger Station there are bathrooms but no water (or at least I’ve never seen it—see the reader comment below). There’s a photo display identifying the wildflowers you’ve been passing if you’re riding in the spring. Summit Rd. is one notch steeper than what you’ve just ridden, more like 8-9%. A sign says the summit is in 4.5 miles, and it’s dead right. Here you will do some work, but again the road contour is constantly varied so the tough stuff isn’t interminable and you don’t get bored. The final 100 yards are just ridiculously steep (RidewithGPS says you touch 17% at one point). Every time I do it I say, “You will not walk, damn you—the summit’s right there!”
When you reach the top, take time to gawk at the views and check out the nifty little Visitor Center ( If you go inside you can literally stand on the tippy-top summit of the mountain, which pokes up through the floor). The very best views aren’t from the parking lot—they’re from the roof of the Visitor Center, which is open to visitors.
When you’re ready to descend, consider the traffic. As I said, the next 4.5 miles back to the Ranger Station is absolutely prime, if the traffic doesn’t spoil it for you.You’ll be going a lot faster than the cars are, so if there are cars in front of you, you’ll be on your brakes and hating it. It’s common to find ourself pulling over and waiting for slow cars in front of you to get a lead. So I strongly suggest you either 1) watch the cars leaving and wait for a long break—at least 30 seconds, or 2) be up there on a Wednesday or at 9 o’clock in the morning.
The descent down South Gate Rd. is faster, more open, wider, and straighter than the stretch from the summit to the junction, and you may prefer it—depends on what you like. Here you’re slower than the cars (you’re faster than you were on the top stretch, but the cars are faster still), so the problem is reversed, but there is passing room and it’s not a big issue. So sez me…but several commenters below say that dangerous motorists are a common threat on the mountain. I’ve never seen them, but I’ve never ridden it when it was busy.
Shortening the route: The classic shorter ride is to ride to the Ranger Station and turn around. The alternative would be to start at the Station and ride to the summit. It depends on how important summits and vistas are to you, and what kind of descending you like—the road above the Station is curvier, smaller, tighter, and steeper.
Adding miles: You’re a few miles from the Morgan Territory Road ride, though they’re unpleasant miles on a bike. Everything else is a substantial car trip away.
Afterthoughts: If the view from the summit is important to you, you want to wait for clear air. That’s hard to find in the East Bay. Your best bets are a clear day in winter, the day after a storm, or when it’s breezy (which brings its own problems.)
There are frequent bathroom opportunities, since many of the campgrounds lining the road have facilities, and water at the summit as well as the entrance gate.
If you ride Diablo in the late summer or fall, you’ll see lots of male tarantulas wandering the road looking for mates, since it’s tarantula breeding season.
Last week, I rode the approach from the North and South gates in the same ride (but only ascended to the summit once.) Great conditions in May.
Riding up North Gate road, a bit before 10am, there was still almost no traffic. In part this may be because the weather report looked like it might rain (but it didn’t!) On the way back down, in the early afternoon, there was quite a bit of traffic. It’s not scary traffic, though. Diablo is peppered with signs warning drivers to be respectful of cyclists, and generally they are.
Can we assume you were riding on a weekday?
No, this was on a Saturday!
I will be climbing Mt Diablo for the first time on Sat. I will be driving my car coming from the Peninsula, my first time in the area. Jay mentioned South Gate Road. Where is the best place for me to park and start my ride?
I would start from Danville Road. Parking isn’t available along the road itself, but there is always lots of shoulder parking in the little residential cul-de-sacs that run off it. I’ve never tried to park around South Gate Road, because I don’t want to start serious climbing right off the bat, but the first half-mile has a lot of informal parking on the grassy shoulder with signs inviting you to use it. I would imagine those spaces are much in demand on a summer weekend—they were 3/4 full on a Wednesday morning in May.
Rode Mt. Diablo last week, from the South Gate road, nice ride. On the way up, saw two turkeys on the road, a male flouting his feathers to a female – it is mating season. A local who has ridden in for many years said to be careful on the descent, he has seen turkeys on the road coming down, and all year, not just during mating season. He said the summers can be wicked hot, to ride in the A.M.
Last few times I’ve ridden Diablo from the south I’ve parked at Diablo Vista Park in San Ramon, from where it’s 4 miles of warmup rollers along Blackhawk road until mt Diablo scenic. Blackhawk is a bit of a slog and there’s no bike lane or shoulder but traffic is light and courteous.
Thanks for the tip on starting at Diablo Vista Park! I parked there and rode Diablo this week and it was great. Covered parking spots (solar panels) and bathrooms at the park. Nice warm up and cool down. The traffic was a little fast along Blackhawk, but I think it had a bike lane added since you posted (at least, I felt like I had space).
North Gate Road is a bit twistier than South Gate, but the road surface can be pretty bad at spots. I prefer the road contour on North Gate, but prefer South Gate as an overall descent due to the smoother surface. Climbing North Gate is also a tad harder.
I rode up to the summit in September of 2016 seven days in a row, each day leaving about 5 AM. I was able to photograph a few sunrises from near the top – really spectacular. The descents are always amazing and you really feel great after leaving the summit. It can be chilly on the descent so bring your windbreaker and some arm warmers at least. I’ve never had issues with the traffic on Diablo. Keep well-charged bright lights on your bike to alert the cars, and a rear view mirror is a must. Make sure your brakes are in good working order and take the turns on the descent nice and slow. If you have disc brakes, they are really great for this terrain, but not mandatory. I usually carry a bottle or two of frozen solid water from my freezer. It stays cold at least half way up. Oh, my climb total for that week was 27,219 feet over 225 miles.
I just completed two loops in Sonoma County and found both extremely stressful. 60-mph traffic with no shoulders or roads in such disrepair that descending was sketchy. The concern about the slow-moving traffic on Diablo seems a little overblown here compared to those experiences. I just have accepted that I can’t descend Diablo as fast as I’d like and assume that a car will be over the center line around each blind curve. But I go to Diablo for the climb, not the descent, and other than December 7 (Beacon Lighting/Pearl Harbor Day) or when masses flock to the top to see snow, I have always been comfortable climbing.
The beacon at the summit of Mt. Diablo is lit one night a year, on Pearl Harbor Day, amid ceremony. See https://www.sfgate.com/bayarea/article/mt-diablo-beacon-pearl-harbor-summit-light-12414751.php.
There is in fact water at the junction, a spigot hidden behind the ranger station. That humble spigot revived me from the throes of dehydration one 100-degree day.
I did this ride twice this summer (2019), both on Sunday mornings, starting the ride before 8am to beat the crowds. I made it a loop, parking at the Rudgear staging parking lot (part of the Iron Horse Trail) near the junction of 24 and 680 in Walnut Creek. Total mileage was 41.5 with 4050 feet of elevation per my Garmin. From this lot, you can take the IHT north, connect to the Ygnacio Canal Trail and this leads you over to Walnut Rd. This provides a nice 10-mile warm up on flat, paved surfaces for runners/bikers only. A left turn onto Walnut takes you over to Northgate Road and from there into the park and up the north side of Diablo. I like climbing the north side better than the south—almost no cars (1 going my way, 3 coming down the opposite way) until I reached the junction. After turning around at the Summit and descending past South Gate, it’s an easy finish to close the loop and return to the parking lot (Rt on Diablo Rd, Rt on Green Valley, Left on Stone Valley, Rt on Danville Rd, and the Rudgear lot is off of Danville Rd).
Definitely fewer cars on Northgate than South.
As a Bay Area local I must take umbrage with “they say on a clear day a person looking north and east can see further than from any other spot on the planet except Kilimanjaro.” Ha! It’s a great view but nowhere near that extensive…the amazing statement is real estate developer hyperbole….here’s the backgraound: https://www.kqed.org/news/11808501/does-mount-diablo-have-the-biggest-view-in-the-world
Regardless thanks for a fantastic site and great information….I’m a huge fan!
I love your site, but you gotta add a North Gate option here. It is the far superior Mt. Diablo experience. There is probably 1/5 the traffic on N. Gate compared to S. Gate.
There are zero parking issues at N. Gate. You can park anywhere along Walnut Ave, preferably around Las Lomas Way.
I personally like to ride up North Gate and down South Gate. The sight lines on S. Gate are much better for descending. Please look out for cars crossing center lines and in general cars being stupid.
There are a number of ways back to your car in Walnut Creek. I personally use:
Diablo Rd -> R. Green Valley -> L Stone Valley -> R Roundhill -> R Miranda (short) -> L Livorna (short dh) -> R Lavender -> L Rudgear -> R Palmer -> R Mountain View -> L Walnut BLVD (not Ave!) -> R Ygnacio Valley (short crappy sidewalk section) -> R Montego -> R La Casa Via -> L on Briones to Diablo Trail (trail is at S end of hospital parking lot, then goes behind hospital and connects to a Canal Trail), R on Canal Trail ->L Las Lomas -> Walnut Ave (your car parked in this area.)