Buttonwillow Raceway Park (The Circuit)
Buttonwillow, California · 4.17 km · 2.59 mi · clockwise
Buttonwillow Raceway Park in Buttonwillow, California is modeled here on The Circuit, run clockwise: 4,171 m (2.59 mi) over the ten-turn card used here, eleven modeled corners once the Turn 8 hairpin is split into 8A and 8B — seven rights and four lefts. The layout is flat; no corner in the model rises or falls more than 0.1 m. The simulated profile bottoms at 44 km/h (28 mph) in 8B, a 13 m-radius right, and peaks at the Turn 10 exit, 166 km/h (103 mph) on the 600 and liter bike; every corner is braked in every class. Simulated lap estimates run from 1:46.6 (liter bike) to 1:51.7 (middleweight twin). Every figure on this page is a physics-simulation estimate, not measured data.
All figures: physics-simulation estimates · generated 2026-10-02 · methodology & assumptions
Track outline © OpenStreetMap contributors (ODbL)
Buttonwillow Raceway Park (The Circuit) — quick facts
Motorcycle track guide · simulation estimates · 2026-10-02
- Layout: The Circuit, 4,171 m (2.59 mi) modeled length, run clockwise
- 11 modeled corners over 10 numbered turns (8 split into 8A/8B): 7 right, 4 left
- Simulated lap estimates: 1:46.6 (liter bike), 1:48.0 (supersport 600), 1:51.7 (middleweight twin)
- Simulated average lap speed: 132.6–138.9 km/h (82–86 mph) depending on class
- Slowest simulated point: Turn 8B, 44 km/h (28 mph) at a 13 m effective radius
- Fastest simulated point: the Turn 10 exit at 166 km/h (103 mph) on the 600 and liter bike
- Longest simulated brake zones: 165 m (541 ft) before Turn 7 and 162 m (531 ft) before Turn 1 on the liter bike
- Flat: 0.3 m (1 ft) of total elevation gain per lap; no corner changes height by more than 0.1 m
Turn 1
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 130 km/h81 mph | 89 km/h55 mph | 149 km/h93 mph | 126 m413 ft | 52 m172 ft | +0.0 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 1 ends the front straight with a 192 m right at a 52.4 m effective radius, flat. The simulation begins braking 126 m before the corner on the supersport 600, 162 m on the liter bike and 87 m on the twin, arriving at 130 km/h (81 mph) and settling at an 89 km/h (55 mph) minimum shared by all three classes. The long arc becomes a drive on the way out: 149 km/h (93 mph) on the 600 and liter bike, 142 km/h (88 mph) on the twin, the first place on the lap where class power shows.
Turn 2
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 107 km/h67 mph | 90 km/h56 mph | 119 km/h74 mph | 87 m285 ft | 53 m174 ft | +0.0 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 3
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 100 km/h62 mph | 74 km/h46 mph | 142 km/h88 mph | 33 m108 ft | 36 m119 ft | +0.0 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 4
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 137 km/h85 mph | 119 km/h74 mph | 158 km/h98 mph | 33 m108 ft | 94 m308 ft | +0.0 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 5
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 124 km/h77 mph | 103 km/h64 mph | 143 km/h89 mph | 120 m394 ft | 70 m230 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 5 is a 195 m left at a 70.1 m effective radius, level at −0.1 m, and it carries one of the longest brake zones on the lap: 120 m on the supersport 600, 153 m on the liter bike, 84 m on the twin. From a 124 km/h (77 mph) entry the minimum settles at 103 km/h (64 mph) in every class. The exit reaches 143 km/h (89 mph) on the two larger bikes and 140 km/h (87 mph) on the twin, all of which is spent again on the approach to Turn 6, the tighter right that follows.
Turn 6
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 88 km/h54 mph | 58 km/h36 mph | 132 km/h82 mph | 72 m236 ft | 22 m73 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 7
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 105 km/h65 mph | 84 km/h52 mph | 129 km/h80 mph | 129 m423 ft | 46 m151 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 7 is a 108 m left at a 46.1 m effective radius, level at −0.1 m, and the liter bike's longest brake zone on The Circuit begins 165 m before it — 129 m on the supersport 600, 93 m on the twin. The simulated entry is 105 km/h (65 mph) and the minimum 84 km/h (52 mph) in every class. The exit is 129 km/h (80 mph) on the two larger bikes and 126 km/h (78 mph) on the twin, heading west toward the Turn 8 hairpin at the far end of the layout.
Turn 8A
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 108 km/h67 mph | 79 km/h49 mph | 79 km/h49 mph | 96 m315 ft | 42 m137 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 8B
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 79 km/h49 mph | 44 km/h28 mph | 117 km/h73 mph | 18 m59 ft | 13 m43 ft | +0.0 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 9
| Entry | Min | Exit | Brake start | Eff. radius | Elev Δ |
|---|---|---|---|---|---|
| 133 km/h83 mph | 98 km/h61 mph | 136 km/h85 mph | 84 m276 ft | 63 m208 ft | +0.0 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 |
|---|---|---|---|---|---|
| 146 km/h90 mph | 122 km/h76 mph | 166 km/h103 mph | 12 m39 ft | 98 m321 ft | +0.0 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