Breckenridge Bike Guide: Backdoor/Sidedoor

A mountain biker finds some air on the Sidedoor trail in Breckenridge, Breckenridge Ski Resort in view behind him.
Courtesy Ben Ferrante
Trail Details

Distance: 3 miles
Rating: Moderate/Advanced
Time: 30 minutes
Elevation: 10,264-10,810 feet (546 vertical feet)
Type: Singletrack loop
Season: Late June to September
Extensions: X10U8, Minnie Mine, Mineral Hill, B&B, Turks
Parking: B&B Trailhead off French Gulch Road

The Sidedoor trail in Breckenridge is a popular downhill flow trail that is only accessed via the new Backdoor uphill trail. Backdoor is a grunt for about a mile but well worth it to come down Sidedoor and enjoy the newly-developed flow trail with various berms, jumps, small drops, step-ups, hits and a nice fast straightaway at the end.
— James Welch, Summit County Mountain Bike Alliance

Riders will need to trudge up Backdoor for about a mile, but it is well worth it in order to come down Sidedoor and enjoy the newly-developed flow trail with various small berms, jumps and drops.

Built by Higher Ground Earth Earthworks’ Troy Heflin, it’s step-ups, hips, and fast straightaway are testaments to the thought put into the terrain, route and ride from Breckenridge locals who know the area and the potential possibilities here best. Backdoor to Sidedoor, for Summit local riders, is an ideal evening loop.

From the B&B parking and trailhead off of French Gulch Road, take the X10U8 trail connector to the intersection with X10U8 proper, a tame route that should take you just under five minutes. Climb up X10U8 proper to the junction with the Minnie Mine Trail and turn left to take Minnie Mine briefly until it merges with the downhill Sidedoor Trail on the rider’s right. Follow Sidedoor along flat terrain for a moment until you can access a hard right to begin climbing Backdoor.

From here, it should take about 15-20 minutes to climb Backdoor’s 559 feet of moderate ascent. Just above the Sidedoor trail you’ll be rollicking back down, before coming to an intersection with Prospect Hill #38, a point at which you will take a right in order to climb briefly. After a moment, hang another right to begin your descent down Sidedoor, a true 2-mile black-diamond downhill that will bring you back to where you began near the X10U8 trail in about half the time, complete with 718 feet of descent mixed with just under 200 feet of uphill fun here and there. Trail features were recently added to Sidedoor, which make this trail more difficult than before, though some alternate easier lines exist.

The Backdoor trail, in blue, taken uphill, accesses Prospect Hill #38 via a 90-degree right-hand turn before another 90-degree right hand turn shortly thereafter puts you on the flowy Sidedoor downhill.
Courtesy Trailforks via Summit County Mountain Bike Alliance

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