The Sourdough Trail is one of the most enjoyable single tracks in Boulder County. It consists of rolling terrain gradually climbing towards Brainard Lake Rd. The trail remains mostly in the trees with occasional views onto the plains. The single track can be continued to Beaver Reservoir. This section of trail is more challenging and is best ridden from Brainard to Beaver Reservoir. A short section of bike hiking (15 Min.) cuts out considerable time on this section of the Sourdough.
From Boulder, go west up Boulder Canyon to Nederland, then north on the Peak to Peak Hwy(Hwy 72), to the turn off for the Colorado Mountain Research Center. Park Along the road where you see the trailhead sign and ride.
Summary: First I have to clarify some incorrect info posted. The C.U. Research Station is SOUTH of Brainard. Secondly, regardless of signs posted the trail is NOT 10-12 miles one way. I've ridden it probably 30 times over 10 years, and it's roughly (yes, intended) 8.5 mi.. Seeing as so many people have bike computers, surprised this wasn't pointed out. / As to the ride, obviously personal opinion varies, but generally it is NOT a beginners trail, and would get mixed reviews from levels above that. It's also not very kind to your body on a hard tail. Also better with tubeless tires. Every single time I ride it after a stretch away, I forget how rocky it is. After a good 1/2 hr. or so though, the flow starts to come back. As to feeling like it's a climb both ways, to an extent it is. You ride to a high point going north to south, although overall you're losing elevation. Technically it's on a par with Walker, or Hall (rock garden side). It's all rideable by a decent rider, but is tough in a few spots. Physically it's no harder than a lot of front range rides and does have some fun flow to it. I've done 2 full out and back trips consecutively ( I know, why?) and it was just a shade over 3 hr's. I'm not a racer, so 2 hrs out and back should be no problem for most people. It's a very good ride (though only average on the fun factor), MUCH cooler up there than Boulder, and you have to be in the "bounce and bash" mood.
Recommended Route: If riding a R/T easier to start at the Research Station. If riding one way, better flow going north to south (again finishing at the R.S.)
Review Date September 4, 2011
Overall Rating 4 of 5
Aerobic Difficulty 5 of 5
Technical Difficulty 5 of 5
Ridden Trail: Ridden Once
Visitors rate this review 5.00 of 5,
Reviewed by: Reid
Summary: I did the NORTH end from Peaceful Valley to Brainard Lake and back down. This is one rocky mutha. You mostly climb for 10 miles across the lower flanks of the Indian Peaks area, kind of like the Peaks Trail in Frisco/Breck. Except Sourdough is painfully hard, pretty much all babyheads. It's the exact last point on the steep vs. rocky graph that is ride-able. I ate about 6 bars, and finished my water right after turning around at Brainard lake. I'd compare it to the rockier parts of Golden Gate SP, harder than Apex, on par with harder parts of Dakota ridge. The second half of the climb seemed to go on forever, and the downhill was not relaxing or that awesome. I saw two other bikers this Tuesday afternoon, one said "There's no flow to this trail." Just grind and smash through some rocks.
I probably won't go back to ride the North end soon. It was hard but do-able, so on the challenge scale, great! On the fun factor, it's like a 3.
Recommended Route: Maybe try and shuttle it, start at the south end, ride up the smooth and rip the rocky DH (some hills though) down to camp, which their are plenty of options for nearby.
Other recommended trails in the same area: West Magnolia, Hall Ranch
Summary: This is a great trail but have plenty of time to do it because the 10.5mi is one way. It is not that difficult make sure you know how to handle your bike because there are multiple rock gardens about 100yds a piece i would reccomend this ride to someone who has been riding more than once and knows how to float rock gardens
Recommended Route: main parking and just keep on going
Other recommended trails in the same area: hall ranch, apex, red rocks
Summary: Sourdough is a fantastic trail. There is a fairly vast network of riding up here. Great, if you like tough, rocky, and technical terrain. If you're looking for buttery smooth, this isn't the place. Generally, the further north you get on this trail, the harder it gets. The area down by the CU research road is less technical and get's fairly gravelly. Sourdough is approximately 12-13 miles long (one way). As Zen rider mentioned, riding this thing as an out and back from one end to the other is an all day affair and a great experience. Although it's mostly all above 8500', the area is very thickly wooded and doesn't yeild a ton of great views to the east. North of Brainard Lake Rd, however, there are a couple spots with absolutely fantastic views of Sawtooth Mt and the Indian Peaks. Remember, the further North you get, the rougher the trail gets. Just stay on course, following marker 835 and you'll be set.
Recommended Route: Most folks reviewing this are starting at the Southern Terminus. I generally ride from the North end, starting at Camp Dick/Peacefull Valley. There's only one way. Stay on the trail marked as 835. Go as far as you want and turn around. More detailed info with pics and maps can be found here: http://www.redstonecyclery.com/bldirt%20camp%20dick%20peacfull%20valley.htm
Other recommended trails in the same area: Baptite/Wapiti, Middle St Vrain Rd, S St Vrain Trail, Buchanan Pass, Coney Creek Rd, too many to mention.
More area trails can be found here: http://www.redstonecyclery.com/bldirt.htm
Summary: Some other reviews on this trail crack me up. Yes, it is rocky in spots. Yes, it is crowded on the weekends (but not like trails nearer to Boulder, Golden, or Denver). Yes, the begining from the Mountain Research road is deceiving with it's width and gravel covering. No, it is not covered in snow most of the year. The first time I rode this trail, I wasn't too excited either. But then I realized you could link three sections together, and THAT is the ride to do, Especially if you think the Soudough trail sucks and is intermediate, or worse yet, for beginners.
It sounds like most reviewers only talk about the section from the big lot off the Mtn Research Center/Rainbow Lakes Road, and then up to Brainard Lake road. You want technical? Do the next section from Brainard to the "Boy Scout Camp" road. And THEN, continue on the other side of that road down to Camp Dick. And then ride back up, and down, and over to where you started.
The first section is fairly moderate with a little challenge here and there. But has some great sections. iIt rolls through some really beautiful forest terrain. (especially this rainy summer we've had)
The middle section crosses the mighty St. Vrain river, which also runs along side the trail for some time. (it also ties into the So. St. Vrain Trail) This section is a mix of smooth cruising trail and large rocky technical. If you thought that the first section was not challenging, ride the middle section! If you can ride the whole thing without even a dab, you get a gold star.
The Third section down to Camp Dick/Peaceful Valley area is quite sweet. A mix of nice singletrack, and a little bit wider sections. Rolling through forest and over rivers (including a nice skinny bridge crossing). Then pick your way down a somewhat/sometimes rocky switchback hillside and end up down near what I think was the start of the Buchannan Pass trail, and Camp Dick.
Then Ride it back! Didn't map it out, but if the first section is about 12 miles R/T, the entire route out and back is probably 25 miles or so.
My ratings are for a geared bike. Although, I rode the entire thing on my Spot singlespeed with a rigid Yo Eddy Fork. (An-aerobic rating would have been higher in that case!) The technical rating is only if you do the entire route.
Take a weekday off, and ride it before the snow flies!
Recommended Route: The entire route.
Other recommended trails in the same area: That would be telling...