West of Bend in the Deschutes National Forest, the Edison-Lava Trail (#31) is a technically challenging 20 mile singletrack spanning 1300. The trails are very loose and dusty, especially if you are riding on the trails shared by ATVs.
To reach the mountain biking trailhead from Bend, head west on Franklin Street and follow to Galveston Street. Turn right heading west on Galveston Street crossing the river. Continue on Galveston Street to the round-about at NW14th Street. Head south on NW14th Street (aka CR372 and FS46) for 17.4 miles. Turn left heading south on FS45 for 4.2 miles. At the sign for Edison Sno-Park, turn right heading west into large parking area.
Begin riding at the south end of the Sno-Park and follow the Lava Butte Trail. Follow the nordic ski traiis for 1.75 miles, passing through rolling lava fields and Ponderosa Pines. Pass Edison Shelter and finally join the main part of the Edison-Lava Lake trail by fuming right 0.25 mile beyond the shelter. The trail begins a long steady climb up past Sheridan Mountain (to your south) and the equally long, steady drop down to the Lava Lakes. At Lava Lakes take a break at the small resort and either head back to the Sno-Park along the same trail or turn right and take Hwy 46 back to the Sunriver turnoff where a right turn will lead you back to your car. Its a 26 mile journey from Lava Lake to your car via this route.
Overall, Edison-Lava Trail is the 23rd most popular mountain bike trail of all 55 mountain biking rides in Oregon.