El Oso Road Professional Review and Guide
"A thigh-burning climb up a scenic ridge on the east slopes of the Mazatzal Mountains. You'll start in saguaro-studded Sonoran desert and end up in ponderosa pine forest. It's located about 85 miles northeast of Mesa. Tread: Doubletrack. The dirt road, FR 143, starts climbing immediately and continuously, with very few breaks.
Of course, you can ride up as far as you like, then turn around for a bomber descent. Just watch for oncoming traffic, especially on weekends. As you start to climb, you pass through Sonoran desert, with its distinctive giant saguaro cactus. Unlike many other doubletracks in the Four Peaks area, the road surface is fairly smooth and rut free.3.8 Whew! The climb moderates for a bit. 4.3 Gear down—it gets steeper."