Coconino Rim Road is a dirt road from Desert View Road in Grand Canyon National Park to the edge of the Navajo Indian Reservation. It makes part of a good loop from the South Rim Visitor Center with AZT - Passage 37 - Grand Canyon - South Rim
for those who are craving some singletrack near the South Rim. It also crosses AZT - Passage 36 - Coconino Rim a couple times offering loop options.
You'll find the Grandview Lookout Fire Tower on the left about one mile from the start at Desert View Road. Climb to the top for a different view of the Grand Canyon. The ranger at the bottom said it was OK as long as you don't go into the top of the tower, which is locked anyway.