{
  "version": "v0.33",
  "date": "2026-10-14",
  "status": "recommended nominal wheel basis; hub interface pending",
  "user_direction": {
    "pneumatic_wheel": true,
    "pressure_0_345_MPa_acceptable": true,
    "removable_ballast_and_positive_restraint_to_be_compared": true
  },
  "wheel": {
    "manufacturer": "Kenda",
    "pattern": "K909",
    "manufacturer_part_no": "109090301B0",
    "size_label": "8x2 / 200x50",
    "nominal_design_diameter_mm": 200,
    "nominal_design_tread_width_mm": 50,
    "construction": "BLK 4P TT",
    "listed_pressure_psi": 50,
    "listed_pressure_MPa": 0.3447378646584,
    "needs_inner_tube": true,
    "actual_inflated_outer_dimensions_mm": null,
    "complete_wheel_cold_speed_pressure_rating": null,
    "actual_wheel_rim_mass_kg": null,
    "confirmed_domestic_exact_SKU": null
  },
  "public_rim_example": {
    "part": "WHL-220F",
    "material_description": "aluminium alloy split rim",
    "stated_fit": "200x50 / 8x2 tyre and tube",
    "axle_diameter_mm": 10,
    "bearings": "2 x 6200Z",
    "bearing_spacer_mm": 24,
    "hub_width_mm": 47.625,
    "selected_for_machine": false,
    "reason": "free-running 10mm axle wheel; not plug-compatible with existing driven 20mm shaft"
  },
  "local_layout": {
    "old_solid_wheel_mm": [
      125,
      25
    ],
    "proposed_nominal_tyre_mm": [
      200,
      50
    ],
    "larger_wheel_requires_local_layout_change": true,
    "no_final_new_frame_dimensions": true,
    "design_reservation_candidate_mm": [
      220,
      70
    ],
    "reservation_is_manufacturer_dimension": false,
    "reservation_does_not_include_complete_hub_valve_or_drive_package": true
  },
  "support": {
    "old_reference_total_mass_kg": 100.14751794869727,
    "test_normal_load_N": 100,
    "longitudinal_force_assumption_N": 100,
    "force_reserve_assumption": 1.5,
    "actual_foot_mu": null,
    "actual_machine_mass_kg": null,
    "cases": [
      {
        "assumed_foot_mu": 0.1,
        "required_total_mass_kg": 163.15459407646853,
        "extra_ballast_over_old_reference_kg": 63.007076127771256
      },
      {
        "assumed_foot_mu": 0.15,
        "required_total_mass_kg": 112.16878342757211,
        "extra_ballast_over_old_reference_kg": 12.021265478874838
      },
      {
        "assumed_foot_mu": 0.2,
        "required_total_mass_kg": 86.6758781031239,
        "extra_ballast_over_old_reference_kg": 0
      },
      {
        "assumed_foot_mu": 0.3,
        "required_total_mass_kg": 61.1829727786757,
        "extra_ballast_over_old_reference_kg": 0
      },
      {
        "assumed_foot_mu": 0.4,
        "required_total_mass_kg": 48.4365201164516,
        "extra_ballast_over_old_reference_kg": 0
      }
    ],
    "ballast_mount": "low, retained, symmetric, detachable blocks on base",
    "positive_restraint_mount": "machine base upstream of measurement chain",
    "confirmed_chamber_structural_anchor": null,
    "restraint_must_react_to_independent_structural_support": true,
    "thin_chamber_liner_is_not_confirmed_anchor": true
  },
  "drive": {
    "target_tread_speed_kmh": 60,
    "wheel_rpm": 1591.5494309189537,
    "wheel_torque_at_Fx100_Nm": 10.0,
    "ideal_friction_power_W": 1666.6666666666665,
    "reference_motor_rating_Nm": 9.8,
    "reference_motor_rated_rpm": 3000,
    "comparison": [
      {
        "motor_rpm_to_wheel_rpm_ratio": 1,
        "wheel_rpm": 1591.5494309189537,
        "motor_rpm": 1591.5494309189537,
        "required_wheel_torque_Nm": 10.0,
        "assumed_transmission_efficiency": 0.9,
        "required_motor_torque_Nm": 11.11111111111111,
        "within_9_8Nm_and_3000rpm_reference": false
      },
      {
        "motor_rpm_to_wheel_rpm_ratio": 1.25,
        "wheel_rpm": 1591.5494309189537,
        "motor_rpm": 1989.436788648692,
        "required_wheel_torque_Nm": 10.0,
        "assumed_transmission_efficiency": 0.9,
        "required_motor_torque_Nm": 8.88888888888889,
        "within_9_8Nm_and_3000rpm_reference": true
      },
      {
        "motor_rpm_to_wheel_rpm_ratio": 1.5,
        "wheel_rpm": 1591.5494309189537,
        "motor_rpm": 2387.3241463784307,
        "required_wheel_torque_Nm": 10.0,
        "assumed_transmission_efficiency": 0.9,
        "required_motor_torque_Nm": 7.4074074074074066,
        "within_9_8Nm_and_3000rpm_reference": true
      },
      {
        "motor_rpm_to_wheel_rpm_ratio": 1.8,
        "wheel_rpm": 1591.5494309189537,
        "motor_rpm": 2864.7889756541167,
        "required_wheel_torque_Nm": 10.0,
        "assumed_transmission_efficiency": 0.9,
        "required_motor_torque_Nm": 6.172839506172839,
        "within_9_8Nm_and_3000rpm_reference": true
      }
    ],
    "preferred_screening_ratio": 1.5,
    "actual_cold_torque_and_losses_verified": false
  },
  "pressure_temperature": {
    "definition": "record measured gauge pressure together with tyre temperature",
    "fixed_volume_ideal_gas_examples": [
      {
        "room_C": 20,
        "room_gauge_MPa": 0.3447378646584,
        "cold_C": -20,
        "ideal_fixed_volume_cold_gauge_MPa": 0.2838730698900698
      },
      {
        "room_C": 20,
        "room_gauge_MPa": 0.3447378646584,
        "cold_C": -30,
        "ideal_fixed_volume_cold_gauge_MPa": 0.26865687119798726
      }
    ],
    "cold_pressure_values_are_not_fill_instructions": true,
    "warmup_pressure_release_interface_to_be_provided": true
  },
  "sources": [
    {
      "id": "S1",
      "role": "manufacturer tyre specification",
      "url": "https://wheelchair.kendatire.com/en-us/find-a-tire/wheelchair/powerchair-scooter/k909/",
      "facts": "109090301B0; 8x2; 200x50; BLK 4P TT; Slick; PSI50"
    },
    {
      "id": "S2",
      "role": "supplier's own rim listing, example only",
      "url": "https://cart.electricscooterparts.com/front-mag-rim-for-200x50-tires",
      "facts": "WHL-220F; split aluminium rim; 10mm axle; two6200Z; spacer24mm; hub1-7/8inch"
    },
    {
      "id": "S3",
      "role": "supplier's own driven rim listing, alternative architecture example",
      "url": "https://electricscooterparts.com/electricscooterwheels.html",
      "facts": "WHL-220R uses72T HTD5M15 drive cog,10mm axle and3inch hub width; not adopted"
    }
  ],
  "previous_draft_pressure_goal_0_5_MPa": "superseded for the recommended first K909 wheel",
  "CAD_manufacturing_release": false
}