This is a steep, bouldery, 1.5 mile trail in Thunderbird park. There are very challenging switchbacks with ~12-18' boulder staircases. Definitely some hiking unless you are an animal.
The trail is accessed via Coachwhip (H1)
from the Pinnacle Peak parking lot, or connecting trails.
Riding clockwise (starting from the northern Pinnacle Peak area) is a less technical downhill (yet more challenging climb) than from the ramada access point by the 59th ave bridge. I would recommend Cholla Loop (H3)
if you are in the area and want a thrill, but it's twice as long.
Don't forget your razor, this thing gets hairy.