Track guide · Preview · 3 of 10 corners open

Thunderhill West

Willows, California · 2.67 km · 1.66 mi · counterclockwise

Thunderhill West is the 2.67 km (1.66 mi) short course at Thunderhill Raceway Park in Willows, California, run counter-clockwise through ten numbered corners — seven lefts and three rights. The circuit sits between 85.8 m and 108.7 m of elevation (roughly 281–357 ft), accumulating about 33 m (109 ft) of climbing per lap, most of it packed into the uphill run through Turns 1 and 2. The simulated speed profile splits the lap cleanly in two: a faster middle sector where Turns 6 and 7 carry minimum speeds above 100 km/h (62 mph) and entries approach 149 km/h (93 mph), and a slow final sector anchored by Turn 8, the tightest arc on the course at a 17.9 m effective radius and a 52 km/h (32 mph) simulated minimum, followed by the near-identical slow Turns 9 and 10. Simulated lap times range from 84.4 s (liter bike) to 86.2 s (middleweight twin). All figures on this page are physics-simulation estimates.

All figures: physics-simulation estimates · generated 2026-07-08 · methodology & assumptions

COMPUTED LINE · THUNDERHILL WEST SIM
Thunderhill West track map with computed racing line
1.66 MI
Lap
10
Corners
109 FT
Climb

Track outline © OpenStreetMap contributors (ODbL)

Thunderhill West — quick facts

Motorcycle track guide · simulation estimates · 2026-07-08

  • Length: 2.67 km / 1.66 mi, run counter-clockwise
  • 10 corners: 7 left, 3 right
  • Elevation range: 85.8–108.7 m (281–357 ft), ~33 m (109 ft) gain per lap
  • Tightest corner: Turn 8, 17.9 m effective radius, 52 km/h (32 mph) simulated minimum
  • Fastest simulated corner entry: Turn 6 at ~149 km/h (93 mph, supersport 600)
  • Simulated lap times: 84.4 s (liter bike), 84.7 s (supersport 600), 86.2 s (twin 650)
  • Simulated average lap speed: 112–115 km/h (70–71 mph) depending on class

Turn 1

Left285 m arc
EntryMinExitBrake startEff. radiusElev Δ
143 km/h89 mph84 km/h52 mph112 km/h70 mph72 m236 ft47 m153 ft+5.4 m+18 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

The lap opens with a left of 46.6 m effective radius that climbs 5.4 m over its 285 m length. In the simulation all three bike classes arrive at essentially the same 143 km/h (89 mph) entry speed, but braking points spread widely with mass and power: the liter bike model begins slowing about 90 m out, the supersport 600 at roughly 72 m, and the lighter, slower middleweight twin needs only about 45 m. Minimum speed converges at 84 km/h (52 mph) for every class, and the uphill grade helps the models accelerate back to around 112 km/h (70 mph) at the exit. These are physics-simulation estimates, not measured values.

Turn 2

Right381 m arc
EntryMinExitBrake startEff. radiusElev Δ
143 km/h89 mph84 km/h52 mph89 km/h55 mph72 m236 ft47 m153 ft+10.1 m+33 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

Turn 2 mirrors Turn 1's 46.6 m radius but bends right and carries the steepest climb on the course — 10.1 m of gain across its 381 m arc. The simulated entry is again about 143 km/h (89 mph) with the same class-dependent brake points (roughly 45–90 m before the corner), and the minimum bottoms at 84 km/h (52 mph). What distinguishes this corner in the model is the exit: because the road keeps rising and curving, simulated exit speed is only 89 km/h (55 mph), the lowest exit of the first half of the lap. The long uphill right effectively caps acceleration until the crest near Turn 3.

Turn 3

Left396 m arc
EntryMinExitBrake startEff. radiusElev Δ
115 km/h72 mph84 km/h52 mph133 km/h83 mph3 m10 ft47 m153 ft+4.0 m+13 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

This corner's walkthrough is in the all-access pack — along with the other 6 locked corners on this track.

Unlock every corner · $59 lifetime →

Turn 4

Left126 m arc
EntryMinExitBrake startEff. radiusElev Δ
129 km/h80 mph75 km/h46 mph139 km/h86 mph72 m236 ft37 m121 ft-1.8 m-6 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

Turn 4 tightens the pattern: a 126 m left with a 36.8 m effective radius, the first corner on the lap that drops downhill (−1.8 m). The simulation enters at about 129 km/h (80 mph) and, with the descent working against braking, starts slowing 51–81 m out depending on class — earliest for the liter bike, latest for the twin. Minimum speed is 75 km/h (46 mph), the slowest point in the first half of the lap. The exit is generous in the model: 139 km/h (86 mph) for the two bigger bikes and 134 km/h (83 mph) for the twin, the highest simulated exit speed on the circuit.

Turn 5

Left153 m arc
EntryMinExitBrake startEff. radiusElev Δ
137 km/h85 mph90 km/h56 mph121 km/h75 mph21 m69 ft54 m177 ft+0.4 m+1 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

This corner's walkthrough is in the all-access pack — along with the other 6 locked corners on this track.

Unlock every corner · $59 lifetime →

Turn 6

Right117 m arc
EntryMinExitBrake startEff. radiusElev Δ
149 km/h93 mph102 km/h63 mph131 km/h82 mph3 m10 ft68 m225 ft-1.2 m-4 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

This corner's walkthrough is in the all-access pack — along with the other 6 locked corners on this track.

Unlock every corner · $59 lifetime →

Turn 7

Left159 m arc
EntryMinExitBrake startEff. radiusElev Δ
144 km/h89 mph102 km/h63 mph135 km/h84 mph24 m79 ft68 m223 ft-0.4 m-1 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

This corner's walkthrough is in the all-access pack — along with the other 6 locked corners on this track.

Unlock every corner · $59 lifetime →

Turn 8

Left141 m arc
EntryMinExitBrake startEff. radiusElev Δ
149 km/h92 mph52 km/h32 mph78 km/h49 mph33 m108 ft18 m59 ft+2.4 m+8 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

This corner's walkthrough is in the all-access pack — along with the other 6 locked corners on this track.

Unlock every corner · $59 lifetime →

Turn 9

Right234 m arc
EntryMinExitBrake startEff. radiusElev Δ
90 km/h56 mph53 km/h33 mph104 km/h64 mph51 m167 ft18 m61 ft+0.1 m+0 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

This corner's walkthrough is in the all-access pack — along with the other 6 locked corners on this track.

Unlock every corner · $59 lifetime →

Turn 10

Left234 m arc
EntryMinExitBrake startEff. radiusElev Δ
90 km/h56 mph53 km/h33 mph104 km/h64 mph51 m167 ft18 m61 ft+0.1 m+0 ft

Supersport 600 preset · simulation estimates · liter-bike and 650-twin figures for every corner ship in the all-access pack · how these are computed

This corner's walkthrough is in the all-access pack — along with the other 6 locked corners on this track.

Unlock every corner · $59 lifetime →