One of the more popular trails in the Nashville area, Lock 4 is approximately nine miles of well-maintained singletrack. Though there is not a significant elevation change, the trail uses natural features and the provided terrain to make it really fun. The trail is divided into segments, plus several off-shoots intended for more advanced riders.
Need to Know Info
Parking is at a dedicated mountain bike trailhead. Though continuous, the trail is divided into and east and west side. The west side is lower and closer to the lake, and stays wet more in the winter. The west side is usually closed until the spring.
The trail is divided into 3 loops, all of which connect to make a continuous 9 miles of single track. Within each section, the trail is subdivided into BLTs that help with navigation. The trail starts with the South Side Trail (Orange), rated at an intermediate level. This is the largest segment of trail at 5.7 miles. It includes BLT 1, followed by BLT 4 through 12. The trail is overall characterized by sections of rocks and roots with a couple quick climbs and two or three nice downhill runs. Within this section are three "advanced" offshoots: Rolling Table, Rock Garden and Smack Down.
Rolling Table is the dirt built jump line. Though short, the lines are well planned and are a lot of fun to run and repeat. There are additions to these lines periodically made by the maintainers of the trail. Rock Garden is a stretch that involves a fun rock ledge drop, probably ~3 feet high followed by a gradual but technical climb. Smack Down is a quick offshoot of the trail that drops you down near the lakeside via a rock ledge drop that can be ridden around followed by a tricky switchback climb to the main trail. The trail ends at a junction near the trailhead where you can either return there or continue on to the green loop.
West Side Trail
The West Side Trail (Yellow) connects to the South Side Trail (Orange) by crossing the street (slightly diagonal uphill) from the exit of BLT 1 and reconnects to it by going directly across the street when exiting BLT 3. This loop is slightly less technical overall, but there are sections with rocks and roots to navigate. Overall this section has some of the best flow at this trail, with easy elevation transitions allowing you to keep your speed up. There is one advanced section here, the Moguls. The yellow loop is also an intermediate level trail and is 1.8 miles long. This loop is on the west side of the trail which does not drain as well, so it is usually closed during winter months.
East Side Trail
The East Side Trail (Green) begins and ends at the confluence of trails near the trailhead. It is 2.1 miles long and rated at a beginner level. The green loop itself is pretty flat with minimal technical terrain. To spice things up, there are two of the longer advanced offshoots here, Spring Trail/Shoreline Trail 2 and Chlorine Hollow. Both of these resemble the orange loop terrain; moderate climbs, short quick descents and some technical aspects.