Methodology
Every number in Toothmap belongs to one of four classes, and the class is printed on the panel where the number appears. If a chart does not say where its numbers come from, that is a bug — tell us.
Exact — ratio math
Speed per gear, rpm at speed, final-drive ratios and their deltas are arithmetic on verified drivetrain data: primary ratio, six gear ratios and stock sprockets for 28 bikes, each compiled from the manufacturer's published specifications (or two independent secondary sources where the manufacturer no longer lists them) and re-checked digit-by-digit by a second pass. Sources are recorded per bike in the open dataset. Tire circumference is nominal from the labeled size — real rolling circumference varies with brand, wear and pressure, so treat absolute speeds as close, not gospel. The top-speed readout is the redline ceiling of the ratio — aerodynamic drag is deliberately not modeled there, and many bikes cannot reach it.
Claimed — manufacturer peaks
Peak power and torque figures are the manufacturer's claims, recorded with their rpm. Nobody's marketing dyno is your bike on your fuel.
Modeled — thrust curves and chain
The thrust chart interpolates a torque curve through the claimed peaks (quadratic segments anchored at the torque peak, the power peak, and a falling tail to redline), applies the overall ratio and a fixed 93% driveline efficiency, and divides by wheel radius. It is a SHAPE for comparing gearing choices — where the pull lives and where it crosses — not a dyno chart. Chain length uses the standard chain-length equation with an assumed 585 mm sprocket center distance; the links/axle numbers are estimates to set expectations before you order parts, not a substitute for measuring your bike. A positive axle shift means the axle moves BACK, a negative one FORWARD — which is why every screen writes the direction as a word instead of a signed number.
Modeled — the speedometer error
The speedometer panel assumes your bike takes road speed from the GEARBOX OUTPUT, the usual arrangement on a chain-drive sportbike: the instrument was calibrated for the stock final drive and the stock rolling circumference, so changing either makes it wrong. A bike that reads from the front wheel is not affected by sprockets or a rear tyre at all, and none of that panel applies to it. What we report is only the error YOUR change introduces — it sits on top of whatever optimism the bike left the factory with, which we do not model because we hold no per-bike data for it.
Exact — rear tyre size
Rolling circumference sets every road speed on this site, so the rear tyre is a control on the instrument rather than a fixed assumption, and the finder searches with the size you picked. The circumference math is exact from the labeled size (nominal, as above). Whether a size physically clears your rim, swingarm or hugger is NOT modeled and we make no fitment claim: the list is sizes near your bike's own fitment on the same rim, nothing more.
Simulated — track corner speeds
The on-track view uses corner-minimum speeds computed offline by a quasi-steady-state lap simulation (friction-ellipse tire model, wheelie and braking limits, aero drag, elevation) on a fixed reference racing line at an expert pace, for three bike classes — the same validated engine behind Apex Lines. Only per-corner numbers ship here, not the line itself. Your lines, pace and conditions differ: the corner gears are a starting point for the conversation, not an instruction. The gear shown per corner is the tallest gear that keeps the simulated corner-minimum rpm at or above the drive floor (85% of the claimed torque peak) — smooth mid-corner with drive left for the exit. Red flags mean the chosen gear sits within 500 rpm of redline; blue means no gear reaches the drive floor there — the gearing is too tall for that corner.
The data is open
The bike dataset (CC BY 4.0) ships with the site: bikes.json. Corrections: contact@anotheronehq.com — name the bike and the primary source that disagrees, and it ships fast. Track scalars carry the simulation disclaimer inside each file. 37 tracks at launch.