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 159 km/h (99 mph), and a slow final sector anchored by Turn 8, the slowest point on the course at a 10.2 m effective radius and a 39 km/h (24 mph) simulated minimum, followed by the similarly slow Turns 9 and 10. Simulated lap times range from 83.0 s (liter bike) to 84.5 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, 10.2 m effective radius, 39 km/h (24 mph) simulated minimum
- Fastest simulated corner entry: Turn 6 at ~159 km/h (99 mph, liter bike)
- Simulated lap times: 83.0 s (liter bike), 83.2 s (supersport 600), 84.5 s (twin 650)
- Simulated average lap speed: 112–114 km/h (70–71 mph) depending on class
Turn 1
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 138 km/h86 mph | 107 km/h67 mph | 122 km/h76 mph | 75 m246 ft | 76 m250 ft | +1.1 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
The lap opens with a left of 76.2 m effective radius that climbs 1.1 m over its 69 m length. In the simulation all three bike classes arrive at essentially the same 138 km/h (86 mph) entry speed, but braking points spread widely with mass and power: the liter bike model begins slowing about 93 m out, the supersport 600 at roughly 75 m, and the lighter, slower middleweight twin needs only about 51 m. Minimum speed converges at 107 km/h (66 mph) for every class, and the uphill grade helps the models accelerate back to around 122 km/h (76 mph) at the exit. These are physics-simulation estimates, not measured values.
Turn 2
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 123 km/h76 mph | 81 km/h50 mph | 112 km/h69 mph | 15 m49 ft | 44 m143 ft | +1.9 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 3
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 115 km/h71 mph | 76 km/h47 mph | 133 km/h83 mph | 54 m177 ft | 38 m124 ft | +1.4 m+5 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
A long left — 282 m at a 37.8 m effective radius, tighter than the first two corners, still climbing 1.4 m. Here the simulation brakes from about 54 m out in every class: entry speed is about 115 km/h (71 mph) after the slow Turn 2 exit, and the model settles at the 76 km/h (47 mph) minimum. The corner then acts as a launching ramp — the supersport and liter-bike models exit at 133 km/h (83 mph), while the power-limited twin manages 131 km/h (81 mph). In the simulated speed profile this is where the faster middle portion of the lap begins to build.
Turn 4
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 107 km/h67 mph | 85 km/h53 mph | 138 km/h86 mph | 84 m276 ft | 47 m156 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 opens the pattern: a 108 m left with a 47.4 m effective radius, gently downhill (−1.8 m). The simulation enters at about 107 km/h (66 mph) and starts slowing 66–93 m out depending on class — earliest for the liter bike, latest for the twin. Minimum speed is 85 km/h (53 mph), the second-highest minimum in the first half of the lap. The exit is strong in the model: 139 km/h (86 mph) for the two bigger bikes and 136 km/h (85 mph) for the twin.
Turn 5
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 142 km/h88 mph | 80 km/h50 mph | 144 km/h89 mph | 9 m30 ft | 42 m139 ft | +1.7 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 6
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 158 km/h98 mph | 100 km/h62 mph | 115 km/h72 mph | 0 m0 ft | 66 m218 ft | -1.4 m-5 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 |
|---|---|---|---|---|---|
| 149 km/h93 mph | 108 km/h67 mph | 122 km/h76 mph | 12 m39 ft | 77 m252 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 |
|---|---|---|---|---|---|
| 147 km/h91 mph | 39 km/h24 mph | 103 km/h64 mph | 12 m39 ft | 10 m33 ft | +2.2 m+7 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 |
|---|---|---|---|---|---|
| 150 km/h94 mph | 41 km/h25 mph | 113 km/h70 mph | 0 m0 ft | 11 m36 ft | +2.2 m+7 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 |
|---|---|---|---|---|---|
| 114 km/h71 mph | 51 km/h32 mph | 145 km/h90 mph | 6 m20 ft | 17 m56 ft | -0.2 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