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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

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

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

Right138 m arc
EntryMinExitBrake startEff. radiusElev Δ
121 km/h75 mph94 km/h58 mph114 km/h71 mph12 m39 ft58 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

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

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Turn 2W

Left210 m arc
EntryMinExitBrake startEff. radiusElev Δ
98 km/h61 mph88 km/h55 mph140 km/h87 mph33 m108 ft51 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

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 3W

Left60 m arc
EntryMinExitBrake startEff. radiusElev Δ
124 km/h77 mph90 km/h56 mph112 km/h69 mph75 m246 ft53 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

Left132 m arc
EntryMinExitBrake startEff. radiusElev Δ
125 km/h78 mph90 km/h56 mph118 km/h73 mph27 m89 ft53 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

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 5W

Right111 m arc
EntryMinExitBrake startEff. radiusElev Δ
143 km/h89 mph108 km/h67 mph132 km/h82 mph12 m39 ft76 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

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 6W

Left144 m arc
EntryMinExitBrake startEff. radiusElev Δ
125 km/h78 mph112 km/h70 mph136 km/h85 mph45 m148 ft82 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

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 7W

Left114 m arc
EntryMinExitBrake startEff. radiusElev Δ
119 km/h74 mph45 km/h28 mph82 km/h51 mph57 m187 ft14 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

Right48 m arc
EntryMinExitBrake startEff. radiusElev Δ
77 km/h48 mph77 km/h48 mph127 km/h79 mph81 m266 ft101 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

Right108 m arc
EntryMinExitBrake startEff. radiusElev Δ
75 km/h47 mph52 km/h32 mph100 km/h62 mph54 m177 ft18 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

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 10W

Left135 m arc
EntryMinExitBrake startEff. radiusElev Δ
100 km/h62 mph55 km/h34 mph120 km/h75 mph15 m49 ft20 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

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 →