Dirty Bismark Loop

 Joe Dirty on September 1, 2018
Dirt Route
On Coalton Trail, Louisville, Boulder County, Colorado
The Dirty Bismark follows the dirt version of the old Bismark road bike loop - this one has a mix of gravel roads, easy singletrack, and gravel paths.
2 overlapping segments.
Distance
Elevation
14.04 miles
5,512 ft minimum
5,958 ft maximum
932 ft gain
942 ft loss
100% dirt
0 images
2 votes
Leave a Comment
 Bryan
on November 21, 2021
A favorite! I do agree with Aaron on the rougher parts. I really enjoy the challenge on 38s but it's hard to recommend it as "gravel" on some of those sections.
 Aaron Clark
on June 7, 2020
There are western sections of this loop that are not typical gravel bike friendly. I ride this weekly and almost never do it on a CX bike even with 38mm tires. Much of it is a blast but sections are slow going on a gravel bike. Baby head rocks and a few drops.