Sourdough Trail

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SHARES
  
AVERAGE RATING
****
3.95 out of 5
View Topo Map

Intermediate
12
miles

Singletrack
↑ 1,300 ft
↓ 400 ft
9,235
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
Directions to Trailhead
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Local Info & Nearby Trails
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 (22)
 



July 26, 2015
Guest   
 
Review: Riding in the dense forest is generally nice as it's quite different to all the trails you can do around Boulder at a lower altitude. The trail is very doable all the way with only a few short quite technical parts where you might have to push your bike over. The millions of loose rocks on the trail, however, can get really annoying as you just lose grip over and over again. So don't expect a nice smooth ride. Overall not the worst but also not the nicest trail I did in this area.

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Bunny Hop

June 28, 2015
gcstandi Bunny Hop  
 
Review: A lot of climbing from the trailhead. Very fun but will leave you gasping for oxygen (if you're a flat lander). At the top, you'll get to the Gateway park entrance. Two miles on the road and you'll get to the Brainard lake. Nice little 4 mile loop around the lake, then head back down Sourdough. The descent is fun and fast.

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Gramcounter

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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Gnarly


July 26, 2013
jkey6 Gnarly  
 
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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Doubletrack

September 19, 2012
abegold Doubletrack  
 
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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Granny Gear

June 11, 2011
pickettz Granny Gear  
 
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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Bunny Hop

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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Epic


July 30, 2010
John Fisch Epic  
 
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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Bunny Hop


June 18, 2010
mwalsh23 Bunny Hop  
 
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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Gnarly


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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Sourdough Trail MTB Trail 3.95 out of 5 based on 22 ratings. 22 user reviews.
Trail Conditions
Trail Conditions          < / > embed
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