Nine Mile Hill (Rio Verde Dr), shown with descent down Reatta Pass. Approx 1,100 ft elevation gain.
This climb starts at the intersection of Forest Rd and Rio Verde Dr, ten miles north of Fountain Hills, not far from the banks of the Verde River and the boundaries of Tonto National Forest. It’s nine miles up Rio Verde Dr to the summit. The first six miles average 3% grade, and then the grade tapers to 2%.
I’ve shown the route descending down Reatta Pass on Alma School Rd, Happy Valley Rd, and ending at Pima Rd.
Due to its wide-open nine mile length (no stop signs or stop lights!) and its gentle, but ever present grades, one training coach I know uses this climb to test his lactate threshold heart rate (LTHR). After an appropriate warm up, if you climb this hill as fast as you can, in time-trial mode, then your average heart rate for the last twenty minutes is a good approximation of your LTHR.