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Big Boulder IMBA Epic


A longer, more difficult variant of the Downieville Classic.

Mountain Biking Severe

33 km
646 m
1.9 km
2-3 hrs
Low Point
882 m
High Point
2.3 km
Big Boulder IMBA Epic Map

IMBA has crowned the Big Boulder version of the Downieville Downhill as one of their venerable Epic rides. Spoiler alert: it’s every bit as epic as you’d expect!


The ride begins by traversing the spine of the Sierras range along the Gold Valley Rim Trail. This trail alone is worth the price of admission. While the Downieville Classic drops straight down the mountain from the top of the pass, Gold Valley Rim offers up unbelievably gorgeous ridgetop singletrack. From this flowy trail, you’ll enjoy stunning views of the Sierra Buttes formation high above and the Lakes Basin area far below you.

The upper section of Gold Valley Rim isn’t very technical, but when the trail drops off the ridge, it gets gnarly in a hurry! The singletrackail funnels into steep rock gardens, over slabs of exposed bedrock, and even offers up optional slabs and rock rolls adjacent to the main trail tread. Many of the rocks sport a rough volcanic feeling, with other slabs consisting of grippy granite. This downhill itself is worth the price of admission, so you’re already way ahead on the amount of time and effort invested!

After dropping out of the first descent, you’ll follow a series of OHV trails to reach the top of Big Boulder. After some descending, it’s time to climb, and you’ll tackle the most significant climb of the entire ride here in the middle. The climb can be a bit challenging, but eventually, you’ll arrive at the top of Big Boulder. Note that this section is the most confusing to navigate of the entire ride. Be sure to refer to FATMAP at every junction along the road—some are not as obvious as you'd think.

The Big Boulder trail offers up a fast, steep descent through a deep, dark forest that drops off the top of the knob and runs all the way into the valley far, far below. Interestingly, there aren’t actually any boulders to be found on this trail. There’s a bit of chunk, but the previous descent off of the ridge top is much more technical than the mostly smooth, fast track found here.

After wrapping up the rip-roaring descent down Big Boulder, you’ll rejoin the classic Downieville Downhill for the high-speed descent down Third Divide and the exposed benchcut pedaling on First Divide. Before you know it, you’ll be back in downtown Downieville planning your next shuttle run!



Widely variable, narrow trail tread with steeper grades and unavoidable obstacles of 15in/38cm tall or less. Obstacles may include unavoidable bridges 24in/61cm wide or less, large rocks, gravel, difficult root sections, and more. Ideal for advanced-level riders.

Medium Exposure

2 out of 4

The trail contains some obstacles such as outcroppings and rock which could cause injury.


3 out of 4

Little chance of being seen or helped in case of an accident.

Best time to visit

between July and October


  • Technical
  • Picturesque
  • Shuttle-run
  • Singletrack
  • In the forest
  • Rock Gardens

Similar routes nearby

Guidebooks in this area