Thunderhill West
Willows, California · 2.66 km · 1.65 mi · counterclockwise
Thunderhill West is the West 2-Mile course at Thunderhill Raceway Park in Willows, California: 2,660 m (1.65 mi) of modeled centerline run counter-clockwise through ten numbered corners, 1W to 10W — six lefts and four rights. The simulated speed profile has a fast middle and a slow infield. Turns 5W and 6W carry minimums above 108 km/h (67 mph) and the highest entry on the lap, 143 km/h (89 mph) into 5W; Turn 7W, a 13.7 m-radius left, is the slowest point at 45 km/h (28 mph), with 9W and 10W next. Simulated lap estimates run from 80.5 s (liter bike) to 82.2 s (middleweight twin). Every figure on this page is a physics-simulation estimate computed from track geometry, not measured data.
All figures: physics-simulation estimates · generated 2026-10-02 · methodology & assumptions
Track outline © OpenStreetMap contributors (ODbL)
Thunderhill West — quick facts
Motorcycle track guide · simulation estimates · 2026-10-02
- Layout: West 2-Mile, 2,660 m (1.65 mi) modeled length, run counter-clockwise
- 10 corners on the official card (1W–10W): 6 left, 4 right
- Tightest corner: Turn 7W, 13.7 m effective radius, 45 km/h (28 mph) simulated minimum
- Largest radius: Turn 8W at 100.7 m; highest simulated minimum: Turn 6W at 112 km/h (70 mph)
- Fastest simulated entry: Turn 5W at 143 km/h (89 mph) in every class
- Longest simulated brake zones: 87 m before Turn 3W on the liter bike; 81 m before Turn 8W on the 600 and the twin
- Simulated lap times: 80.5 s (liter bike), 80.7 s (supersport 600), 82.2 s (twin 650)
- Simulated average lap speed: 114–116 km/h (71–72 mph) depending on class
Turn 1W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 121 km/h75 mph | 94 km/h58 mph | 114 km/h71 mph | 12 m39 ft | 58 m191 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 2W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 98 km/h61 mph | 88 km/h55 mph | 140 km/h87 mph | 33 m108 ft | 51 m168 ft | -0.7 m-2 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 3W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 124 km/h77 mph | 90 km/h56 mph | 112 km/h69 mph | 75 m246 ft | 53 m174 ft | -0.3 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
A short left, only 60 m long, at a 52.9 m effective radius and nearly flat (−0.3 m). What the simulation shows here is the heaviest braking of the first half of the lap: from a 124 km/h (77 mph) entry, the supersport 600 begins slowing 75 m out, the liter bike 87 m out — the longest brake zone on the circuit for that class — and the twin 54 m out. Minimum speed is 90 km/h (56 mph) across the classes. Because 4W follows almost immediately, the exit is contained: 112 km/h (69 mph) for the two larger bikes and 110 km/h (68 mph) for the twin.
Turn 4W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 125 km/h78 mph | 90 km/h56 mph | 118 km/h73 mph | 27 m89 ft | 53 m175 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 5W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 143 km/h89 mph | 108 km/h67 mph | 132 km/h82 mph | 12 m39 ft | 76 m251 ft | -0.8 m-3 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 6W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 125 km/h78 mph | 112 km/h70 mph | 136 km/h85 mph | 45 m148 ft | 82 m270 ft | -0.7 m-2 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 7W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 119 km/h74 mph | 45 km/h28 mph | 82 km/h51 mph | 57 m187 ft | 14 m45 ft | +2.0 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
The tightest corner on the course: a 114 m left at a 13.7 m effective radius, climbing 2.0 m (7 ft). The simulation approaches at 119 km/h (74 mph) and brakes hard and early — 57 m out on the supersport 600, 63 m on the liter bike, 45 m on the twin — down to a 45 km/h (28 mph) minimum, the slowest point on the lap by a clear margin. The uphill grade and the tight arc keep the exit low at 82 km/h (51 mph) in every class. This is where the fast middle sector ends and the slow infield begins; the following two corners, 8W and 9W, keep the model slow until 10W.
Turn 8W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 77 km/h48 mph | 77 km/h48 mph | 127 km/h79 mph | 81 m266 ft | 101 m330 ft | +0.3 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 8W has the largest effective radius on the course, 100.7 m, but it is short — 48 m — and nearly flat (+0.3 m). The simulation reaches it at only 77 km/h (48 mph), still recovering from 7W, and the minimum speed equals the entry speed: the model logs an 81 m brake marker on approach in every class, the longest on the lap for the 600 and the twin, but sheds nothing inside the arc. The corner is effectively an acceleration zone, with the exit climbing to 127 km/h (79 mph) on the supersport 600 and liter bike and 123 km/h (77 mph) on the twin before the next hairpin, 9W, arrives.
Turn 9W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 75 km/h47 mph | 52 km/h32 mph | 100 km/h62 mph | 54 m177 ft | 18 m59 ft | +0.8 m+3 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 10W
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 100 km/h62 mph | 55 km/h34 mph | 120 km/h75 mph | 15 m49 ft | 20 m66 ft | -0.7 m-2 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