The Sidle 73 MTB track has been developed to enable mountain bikers wanting to ride a loop from the Broken River to Craigieburn Ski Field roads to avoid having to ride the section of State Highway 73 between the two roads.
In 2012 the Department of Conservation and the Castle Hill Community Association together with Ground Effect signed agreements that enabled the Sidle 73 track to come in to being. After final approval from DOC was obtained, the track was constructed by work parties organised in November 2012 by Ground Effect. The track was officially opened on the 23rd February 2013.
The Sidle 73 MTB track connects the Cave Stream campground on the Broken River Ski Field access road with the Craigieburn Ski Field access road, avoiding 1.5km of tarmac on State Highway 73. The track begins at the Cave Stream Picnic area and ends on the Craigieburn Valley Ski Field Road. In part the trail uses an old 4WD track and has been constructed as a walking and biking track of intermediate grade.