Four Seasons of Horsetooth (4SOH) Mountain Bike Challenge

Race - Nov 21, 2025

Dogs Leashed

E-Bikes Unknown

The Four Seasons of Horsetooth (4SOH) Mountain Bike Challenge course follows some of the best trails along the Northern Colorado Front Range. It's a challenging 20+ miles with three, lung-busting climbs and a mix of technical and flowing descents.

The 4SOH Challenge is a four season stage race that takes place on the equinox/solstices. This free grassroots un-event begins each fall and encourages participants to ride the course each season.

The current leaderboard, rules, and additional information can be found at 4SOH.org.

The course starts and ends in the Lory State Park Timber parking lot.

Start at the Timber trailhead at Lory State Park. At the first intersection, bear left, crossing the road to the East Valley trail. Head South on the winding singletrack of the East Valley trail. The valley trails are mostly smooth dirt with occasional rocks. Continue south for 2.5 miles. At the Arthur's Rock trailhead, bear left and then turn right onto the South Valley
trail. Continue south for ~1 mile. At the next intersection, bear left onto Nomad, then bear left again onto the Shoreline trail, continuing south for 0.9 miles.

Continue onto the Swan Johnson Trail. In a half mile you'll reach the Soderberg trailhead. Cross the road and continue south through the parking lot and onto the Inlet Bay trail. In 1.3 miles, you'll reach the Blue Sky trailhead. Turn right onto County Road 38E and climb to the main Horsetooth trailhead. Take the leftmost trail, South Ridge, out of the parking lot, and buckle up for the 2.3-mile climb. Turn right onto Wathen, open the suspension, and descend to the Spring Creek trail.

Turn left on Spring Creek, a couple hundred yards later turn right onto Herrington trail. Climb until you reach the intersection with Towers Road. Turn left and climb to the intersection with Carey Springs. Turn right and descend until you meet Loggers and hang a right. Continue to the Sawmill intersection. Turn left onto Sawmill. Descend on Sawmill and Sawmill Connector until you reach South Valley Trail.

Turn left and head north on South Valley Trail. Continue north on West Valley Trail until you reach Kimmons. Turn left and climb up the tech on Kimmons until it intersects with Timber Trail. Enjoy the view. Then descend Timber back to the trailhead you started from.

4SOH began in 2014 and was conceived by the infamous Beet Juice.