ROAD
TOOT Gear Calculator — Road / Gravel
Drivetrain 700C · 650B · 32" (ISO 686) · tires 23–65 mm — with a physics solver for power, speed and CdA.
1 · Single calculator
ISO rim bead seat diameter, in mm.
Geometric
Measured
Ø = BSD + 2 × tire section, then × squish factor.
Ø: — mm
Circumference: — m
Ratio
—
Development
—
m per pedal rev
Speed
—
km/h at cadence
Wheel rpm
—
rpm
2 · Dual option comparator
OPTION 1
Geometric
Measured
Ø: — mm
Circ: — m
Ratio
—
Development
—
m per pedal rev
Speed
—
km/h
Wheel rpm
—
rpm
OPTION 2
Geometric
Measured
Ø: — mm
Circ: — m
Ratio
—
Development
—
m per pedal rev
Speed
—
km/h
Wheel rpm
—
rpm
dev = circumference × chainring/cog
speed [km/h] = dev × cadence × 0.06
Difference: —
3 · Physics model — rider, bike, environment
Rider + bike + kit
Frontal area × Cd
See presets below
Negative = tailwind
Computed
Manual
ρ = — kg/m³
4 · Performance solver
Speed
—
km/h
Rider power
—
W · — W/kg
CdA
—
m²
Required cadence
—
rpm · —
Power split at the wheel
Aerodynamic —
Rolling —
Gradient —
Drivetrain losses —
Time over distance: —
—
| Gear | Ratio | Development (m) | Cadence (rpm) | Δ |
|---|
Wheel and circumference follow the selected reference gear.
Model
Ppedale = [ ½·ρ·CdA·(v+w)²·v + Crr·m·g·cosθ·v + m·g·sinθ·v ] ⁄ η — steady state, no acceleration term.
ρ from the ISA barometric formula with a humidity correction (Magnus vapour pressure).
Rolling Ø = BSD + 2 × nominal section, corrected by the squish factor. For race numbers, use the measured rollout.
ρ from the ISA barometric formula with a humidity correction (Magnus vapour pressure).
Rolling Ø = BSD + 2 × nominal section, corrected by the squish factor. For race numbers, use the measured rollout.
1.000 = pure geometry. Typical under load: 0.985–0.995.
