One of the best singletrack rides in the valley. It's a great loop including lots of climbing on the bike path to 7 miles of great singletrack.
Park at the Rodeo Parking lot soon after entering Snowmass Village. This ride is best done clockwise (though either direction is good), so ride up the Brush Creek Bike Path
until you are just below the main ski area. It's a good bit of climbing on the bike path system, with several junctions. Keep climbing until you are just below the base of the main ski area.
Cross Brush Creek Road
at a point just before the road makes a final, sweeping turn that brings you to the base of the ski area. At this spot, you'll cross Brush Creek Road
and take Divide Road 100 yards to the Rim Trail
Start off with a 700' vertical climb. The trail is well-built for bikes though, with widely-rounded switchbacks and a very smooth surface, so it's a very enjoyable climb. It's pretty exposed to the southern sun, so it could be quite hot on a warm sunny day.
Once at the top, take a left and go 100 yards to the high point and enjoy the remarkable 360 degree view.
Return those 100 yards, then continue on slightly descending, fast and fun singletrack right along the rim. There are occasional breaks in the trees that are worth stopping for and taking a peek.
More fun descending, sometimes through forest, takes you to a saddle point and a road crossing. This is a bailout option if you're in a hurry or tired. Otherwise, continue on, with some moderate climbing until you get to one final 400' climb.
Like the first climb, the surface is nice and it's well laid out for bikes, and it's over pretty fast. There are more great views from a bench at this high point.
Now it's a pure descent all the way to the car, and it's a blast: singletrack all the way through some aspens, but mostly sage meadows on nicely contoured trail. The views are astounding if you can take your eyes off the trail for a second. It ends all too quickly with a short stretch of a bike path that leads back to the parking lot.