The Glenorchy Mountain Bike park was developed in 2005, and a lot of work has been put into the trails.
To get there head to the main road of Glenorchy, then turn on to Tolosa St and follow it right to the end. Go through the gate and ride up the road for 100m to get to the 4X track.
You can also get there from Mt Wellington via Knights Creek track.
There is now a web site for the park:
Park map from Hobart Wheelers as of Sep 2005