physicalproperties.json

Default gearing and current limits shared by every module, unless a module's own JSON file overrides gearing. Parsed into swervelib.parser.json.PhysicalPropertiesJson.

{
  "gearing": {
    "drive": {
      "gearRatio": 6.75,
      "diameter": 4.0
    },
    "angle": {
      "gearRatio": 12.8
    }
  },
  "statorCurrentLimit": {
    "drive": 40,
    "angle": 20
  }
}

Field	Type	Required	Description
gearing.drive.gearRatio	number	yes	Drive motor reduction, as the X in X:1.
gearing.drive.diameter	number (inches)	yes	Wheel diameter.
gearing.angle.gearRatio	number	yes	Angle/steering motor reduction, as the X in X:1.
statorCurrentLimit.drive	number (amps)	no (default 40)	Drive motor stator current limit.
statorCurrentLimit.angle	number (amps)	no (default 20)	Angle motor stator current limit.

See Standard Conversion Factors for gear ratios/wheel diameters of common COTS swerve modules.

Several fields that existed before 2026.8.05 are gone: friction, steerRotationalInertia, robotMass, rampRate, wheelGripCoefficientOfFriction, optimalVoltage. See Schema Changes for why.