Sourdough Trail

3.95 out of 5
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↑ 1,300 ft
↓ 400 ft
elevation (ft)

Out & Back
Trail Description
About this trail
This section runs between 9200-10200' elevation. The altitude, climbs, and constant rockiness make this an overall tough ride. There aren't many large-rock sections, but plenty of small-medium ones to keep it a little rough most of the time, and many small sharp ones that have given me pinch flats and holes in the sidewalls. As of 2012 it seems they've done some trail work and smoothed out several sections that where once much harder. There are several fallen trees you'll have to work around, some have been turned into fun little log piles to ride over. The ride is mostly through dense forrest perfect for hot summer days. There are maps at both ends of the trail, check out the map at the north end to see more trail options that continue from the trailhead on Brainard Lake Rd.
added by JohnsXCbikeTrailblazer April 12, 2005
Trail Features
Trail features
  • Lift Service
  • Drinking Water
  •   Night Riding
  • Pump Track
  • Restrooms
  • Winter Fat Biking
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Trail Check-ins
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Recent Trail Check-ins     (9 total check-ins)
  Jon_Gotow   on Sep 6, 2014
  Jon_Gotow   on Aug 23, 2014
  antho_bldr   on Aug 17, 2014
  antho_bldr   on Aug 3, 2014
  Tr0gd0r   on Jul 20, 2014
Photo & Video Gallery (28)
Trail Photos & Videos (28)
Reviews (20)

October 8, 2013
Review: A ride relatively close to the Boulder area with the atmosphere of an alpine singletrack ride! You see yourself in the middle of a vast and dense forest, yet you can easily hear the traffic from State Highway 72 to your right on several occasions. The first two miles are definitely the toughest. However it is mostly doable for any strong climber, just a couple of short highly technical sections. The reward for that work is smoother singletrack practically the rest of the way! Nice view of North Boulder, Boulder foothills, and the Eastern Plains in between the trees about halfway through. It is approximately 6 miles from the trailhead to Brainard Lake Road, but plan on at least 3 hours to finish an out and back ride.

Similar Trail: Colorado Trail-segment west of Kenosha Pass

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July 26, 2013
Review: This trail is really great. The dense vegetation makes this a very different experience from the bone dry trails around Boulder and Golden. It's not quite as fast and buffed out as other front range trails but that's because it isn't traveled nearly as much. The solitude makes this trail worth the drive. I have only done it as an out-and-back from Rainbow Lakes to Brainard Lake (12 miles round trip) which I think is a good way to do it since you do most of your climbing the first half and enjoy the tight and moderately technical singletrack on the way back down to the car. I only say moderately technical because the rocks and roots are generally pretty small, but make no mistake, there is PLENTY of loose rock on this trail. This review is for Sourdough South only (south of Brainard Lake trailhead).
P.S. Check the weather before you go! I got caught in a surprise thunderstorm.

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September 19, 2012
Review: Nice ride in the woods. The altitude makes the climbing tougher. Compaired to other places I've ridden didn't find the rocks a problem.

Similar Trail: Lots of trails in the woods thruout the area. South of Nederland there's a fun system that connects the area.

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June 11, 2011
Review: I was riding this trail this past fall, and I almost died. Not because of the trail, most of which is covered in loose rock (actually a very fun trail), but instead because of moose. Flying down the single track back to the car park, a calf ran out into the trail about 15 feet ahead of me and continued to run straight down the trail. Luckily I was able to slam on the breaks because the doe followed the calf onto the trail, and was about 4 feet away from t-boning my bike. And to think, the one time I don't have my helmet cam with me! Overall, check this trail out.

Similar Trail: Nederland

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September 8, 2010
Review: This trail is more of an intermediate plus, borderline advanced. Very rocky and bumpy, on the way down, my hands were numb and sore. Great trail for a hot summer day as it's surrounded by woods. Going up, it's almost constant climbing. First mile or so of the trail is covered with loose rocks and sandy gravel.

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July 30, 2010
Review: Some rocks are amusing, some are annoying; this ride has plenty of both. And roots. I wouldn't want to ride a hardtail here (unless maybe if it was a 29er). The combination of altitude and rocks provide a physical challenge, but the grade is generally pretty easy, so it's all doable. This one trail has lots of options; it's great as an out-and-back (the descent is way fun), a point to point with a shuttle from Peaceful Valley, a loop if you don't mind a long stretch of pavement with more climbing, or you can connect to many trails in the extensive South St Vrain network.

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June 18, 2010
Review: Absolutely awesome. This trail is rocky, there's no question, but it's not bad on the way up at all- easy to pick lines and power through/ over most everything on the trail. Coming down is fast and fun- some sections are smooth and twisty goodness, while others are just constant rock fields- not too bad, just numb hands :). Beautiful woods and gorgeous trail.

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August 5, 2009
Review: Good trail. First few miles kinda blow, climbing up some scree, loose rocks, stuff to that effect. After those first few miles it turns way better, good singletrack, parts are technical with rock gardens (but not overly technical, all ride-able). Climb the whole way up pretty much, but it's never a real steep climb, all manageable. Fun downhill on the way back, nice singletrack with a bunch of rocks and stuff to make it a little bumpy/tricky.

Similar Trail: Heil Ranch

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July 26, 2009
Review: I rode this trail from the Sourdough trail head off highway 72 to the reservoir. Out and back I figure it was about 24-25 miles. The first 2 or 3 miles are a bit rocky, but totally manageable. It is deceiving because I felt that the decent back would have been awesome, perhaps my expectations were too high. Don't get me wrong, the downhill at the end was fun, but I've had better experiences on different trails. If you continue past Left Hand Canyon Creek and the paved road, there's an interesting downhill. It's difficult to describe - it's not one full section of rock gardens and techy parts, but various large, round rocks placed all of the trail. It makes it difficult to really pin it and enjoy the decent. After reaching a few trail junctions, the decent smoothed out and was more enjoyable, but I was frightened for the climb out. It turns out that the climb wasn't nearly as bad as anticipated, but I hesitate to say that the decent to the reservoir was worth it. It was a pretty view, but the work to get out...meh. There are better epic rides out there (Kenosha Pass, Buffalo Creek, Monarch Crest, etc). With that said, I would do this trail again. It's always nice to spice up a routine of weekend rides.

Similar Trail: Kenosha Pass, Buffalo Creek

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May 27, 2009
Review: Recently rode it once again, I coudln't help but notice how much smoother the trail is now(June2012), they've done a lot of work on it and it's noteably less rocky than before, yet it looks like someone went on a tree tipping rampage where you'll have to climb over or around some fallen trees. Still a tough ride considering the altitude and amount of climbing, love all the trail options from the Brainaard Lake rd trailhead for when I'm feeling up to more riding, the views up at Brainard lake are worth the extra climbing, and if you don't want to pay the bike toll at the booth, there's a rarely-used trail along the North side of the road, which I should say is quite a technical mess since it seems rarely used.* Review edited 6/5/2012

* Review edited 6/5/2012

Similar Trail: South Saint Vrain

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Sourdough Trail MTB Trail 3.95 out of 5 based on 20 ratings. 20 user reviews.
Trail Conditions
Trail Conditions          < / > embed