In the San Pedro Matir National Park south of Colonet (7 mi.) off Highway 1, try the 40 mile jeep road up the snow capped Picacho del Diablo (10,154). The park has a complex network of mountain bike trails that require excellent map reading skills. Come in April to June for wildflowers and bubbling brooks.
Note: Prior to 1997, the topographic maps developed by the federal government used the NAD27 CONUS datum. Starting in 1998, the government transitioned to the ITRF92 datum (some maps show both datum), which is pretty much identical to the WGS84 datum.
Overall, Sierra San Pedro Martir National Park is the 10th most popular mountain bike trail of all 24 mountain biking rides in Mexico.