The west side of Sonora Pass climbs 9.1 miles (14.6 km) at an average 7.2% from the junction of Highway 108 and Kennedy Meadows Road, at 6,306 ft (1,922 m), to the pass at 9,623 ft (2,933 m). That’s 3,455 ft (1,053 m) of climbing, with almost all the hard part up front. It’s California’s second-highest paved pass, about 330 ft (100 m) below Tioga Pass, and one of the steepest in the United States.
What the climb is like
- The first 3 miles (5 km). The climb starts with a bang: a sign warns of 26% grades and, although they don’t get that steep, nearly all the double-digit pitches are packed into the first 3 miles, with a brief breather around mile 1 (km 1.6). The hardest quarter mile, at 15.4%, starts around mile 0.5 (km 0.8).
- The middle. The grade eases through pine forest and includes a 0.6-mile (1 km) descent around mile 3.7 (km 6).
- The finish. After the descent, the road climbs again at a sustained grade to the pass.
In all, almost half the route is between 5% and 10%, 1.6 miles (2.6 km) between 10% and 15%, and about 0.4 mile (650 m) between 15% and 20%. Climbfinder gives 14.6 km and 1,053 m; PJAMM, 14.7 km and 1,042 m.
When to go, services and altitude
Highway 108 closes for snow, usually from November to May. The best time to ride is July to September. There’s no food or water on the entire climb: stock up first in the valley towns. Traffic is light, because the road is narrow and not recommended for large vehicles.
The pass is at nearly 9,800 ft (3,000 m). If you live near sea level, try to spend a couple of nights at 6,500 ft (2,000 m) or higher first; on the east side of the Sierra, Lee Vining and Mammoth Lakes make good bases. From the pass you can descend east toward Leavitt Meadows and climb back up: an out-and-back over both sides is about 37 miles (60 km) and more than 6,900 ft (2,100 m) of climbing.
What gearing to use
The 12-17% pitches at the start call for low gears. At 3 W/kg (watts per kilo of body weight) and 159 lb (72 kg), you’ll be doing about 3.9 mph (6.2 km/h) on 15%: on a 34x34 that’s about 49 rpm. If you’re at 2.5 W/kg or less, fit a 32x36 or a gravel drivetrain. Run the numbers in the gear calculator.
Frequently asked questions
How long does it take to bike up Sonora Pass?
A 159 lb (72 kg) rider on a 21 lb (9.5 kg) bike takes about 1 h 12 min at 3 W/kg (216 W), 1 h 26 min at 2.5 W/kg and 56 min at 4 W/kg. Work out your own time with your weight and power in the calculator on this page.
Does Sonora Pass really have 26% grades?
Not on this side. At the start a sign warns of 26%, but the databases give a maximum of 15.4% over a quarter mile, 400 m (PJAMM), and 17.2% over 100 m (Climbfinder). Even so, there are more than 2 miles (3 km) above 10%, almost all in the first 3 miles (5 km).
When is Sonora Pass open?
Highway 108 closes in winter for snow, usually from November to May. Check Caltrans road conditions before you go.