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
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
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 143 km/h89 mph | 84 km/h52 mph | 112 km/h70 mph | 72 m236 ft | 47 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
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 143 km/h89 mph | 84 km/h52 mph | 89 km/h55 mph | 72 m236 ft | 47 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
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 115 km/h72 mph | 84 km/h52 mph | 133 km/h83 mph | 3 m10 ft | 47 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
Turn 4
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 129 km/h80 mph | 75 km/h46 mph | 139 km/h86 mph | 72 m236 ft | 37 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
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 137 km/h85 mph | 90 km/h56 mph | 121 km/h75 mph | 21 m69 ft | 54 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
Turn 6
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 149 km/h93 mph | 102 km/h63 mph | 131 km/h82 mph | 3 m10 ft | 68 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
Turn 7
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 144 km/h89 mph | 102 km/h63 mph | 135 km/h84 mph | 24 m79 ft | 68 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
Turn 8
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 149 km/h92 mph | 52 km/h32 mph | 78 km/h49 mph | 33 m108 ft | 18 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
Turn 9
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 90 km/h56 mph | 53 km/h33 mph | 104 km/h64 mph | 51 m167 ft | 18 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
Turn 10
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 90 km/h56 mph | 53 km/h33 mph | 104 km/h64 mph | 51 m167 ft | 18 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