“A very technical descent from the Brainard Lake parking lot to Middle St. Vrain Road.”
— Brian Smith
North Sourdough is a technical trail that features constant rocks and roots throughout. For those of you who have ridden in New England, this trail may be reminiscent to you. If I had to pick one word to describe this trail, "flow" would certainly not be it. That said, North Sourdough is a blast to ride.
There are not very many super steep sections but it is, as previously stated, a sustained technical challenge. Bounce and weave your way through pine and aspen forest and keep an eye out for wildlife. Moose and Elk are always possible to encounter. This trail is also a great fall ride if you'd like to do some leaf peeping.
Find the trailhead directly behind the main parking area and get straight into the fun. At an intersection with South Saint Vrain Trail just after crossing a bridge, keep straight on North Sourdough. This is a well signed intersection. Expect a few punchy, technical climbs but for the most part you'll be pointed down. Eventually, you'll cross a dirt road. This is a good bail out point to the Peak to Peak highway if you did not enjoy the first portion of this trail.
If you did like what you rode, continue onward. The trail will offer more thrills as it winds its way to the terminus at Middle St. Vrain Road (CO hwy 92).