ENVIRONMENT — air, wind & surface

ρ is computed from altitude + temperature (barometric formula); Crr comes from the surface. Thinner air up high = faster on the flat; a headwind or gravel = slower. Wind feeds the grade×power matrix and the routes; the audit + acceleration stay at the windless calibration.

GAME ROAD SURFACES — the story-ride consequence · docs/fable/48

Each story-ride road surface carries a REAL rolling-resistance cost, not just a texture. The speed multiplier below is derived from THIS page's own solver at a reference operating point (200 W, flat, reference rider) — the same watts cover this fraction of the ground on that surface vs. smooth asphalt, so a muddy or cobbled sector is felt as lost distance, never a faked watt. Soft ground (dirt/snow/mud/sand) bites harder on climbs (the tyre sinks — a term the steady-state balance alone misses); the last column shows the total at an 8% climb.

Run at the reference rider — 84.5 kg · CdA 0.36 · Crr 0.005 · ρ 1.225 · η 0.97, sea level / 15 °C. Fixed on purpose: the sliders above move every other table on this page, but they must not be able to paint this one green. The two flat/5 %-climb anchors are the ones already cited in lib/physics.ts.

We sit high on all 8 of them — 8/8 fast, mean +5.0 %. That is an offset, not scatter, so here is where it comes from rather than an average that hides it. The references were not all taken at one setup: hold everything else and ask what single value would make our own solver land exactly on each published speed — the last column. Where air resistance sets the speed they imply CdA 0.38–0.45 m²; where gravity does, 86–91 kg total. Ours is a 0.36 m² hoods/tops position at 84.5 kg — more aero and lighter than what those numbers describe, which is the whole gap. Feed a rider back in at roughly CdA 0.41 / 89 kg and the deltas scatter either side of zero instead of stacking up. So the offset is a difference in who is riding, not in the physics: 8/8 land inside a tolerance band that was set before any of this was measured.

Each cell is solveSpeedKmh(power, grade, rider) — the exact value the ride uses. Read down a column and you can see the balance tip: At 250 W the flat is aero-dominated, the 8 % climb is gravity-dominated.

Each route integrates the steady-state speed segment-by-segment at a constant 3.0 W/kg. “rpm” is the cadence in the gear closest to 90 — yellow means no gear in the All-round (54/39 × 11-30) drivetrain keeps you in the 80–100 band at that speed.

LEADERBOARD PAR — “the target you race”

The OutRide Arcade Rating + Time-Trial medals rank you against a par time, not raw speed — so a flat sprint and a mountain climb compare fairly. Each par below is stageTargetSec = this same solveSpeedKmh model run for a reference rider of that W/kg class (equipment-neutral, 90% of class FTP). Notice steep climbs cost a weak (E) rider far more than a lookup table would ever guess — that's gravity, done honestly.

Ride under your class's par → positive Arcade Rating (1000 = par). Because it's par-relative, no single fork line is a “farm” — every route rewards the same relative effort equally.

A 10 km course that averages 2.0% is not one time — how the climb is distributed changes it a lot. profileTimeSec integrates the same solveSpeedKmhfoot-by-foot over the real elevation profile — the honest way to time a course, and the model behind profile-aware ghost + par times. Rolling terrain is genuinely slower: the time lost grinding steep pitches dwarfs the time won on the descents (drag caps downhill speed), so a “Rollers” course with 30% descent is the slowest of all, not the fastest. All at 3.0 W/kg.

At 0% average every shape is identical (nothing to distribute). The penalty grows with the average grade and the “peakiness” of the profile — which is exactly why a naive average-grade lookup would hand out unfair targets on a hilly course. Same physics, done honestly.

Driven by the actual ride integrator step() from a standstill. The terminal speed is identical to the solver — only the wind-up is now Newtonian, so a 84.5 kg rider on this equipment shows real launch lag and a sprint has punch. Heavier mass or less power = slower to wind up.

GEAR / CADENCE LADDER — All-round (54/39 × 11-30)

A row marked has a gear that holds the target cadence band at that speed; at the top and bottom of the range you’d spin out or grind — exactly what a real drivetrain does.