Tire pressure monitoring provides real-time and historical pressure and temperature data captured via TPMS (Tire Pressure Monitoring System) sensors mounted on each wheel position. The values that are provided by the endpoints will vary based on the TPMS hardware you are using and where those sensors are located. Maintaining optimal tire pressure is critical for fuel efficiency, tire longevity, and vehicle safety.
Overview
The Smart Tire API provides two ways to access tire pressure data:
- Latest tire data - Get the most recent pressure readings for one or more vehicles using the Tire Events endpoint with
inspectionTypes=TIRE_PRESSURE
- Pressure history - Get historical pressure events for a specific vehicle over a date range using the Tire Pressure Events endpoint
Pressure Measurements
Each pressure reading includes the following measurements:
| Field | Unit | Description |
|---|
pressure | Pascals (Pa) | Raw measured tire pressure at the time of reading |
normalizedPressure | Pascals (Pa) | Pressure adjusted to a reference temperature of 20°C |
temperature | Celsius (°C) | Tire temperature at the time of the reading |
Why normalized pressure mattersTire pressure changes with temperature — approximately 1 PSI (6,895 Pa) for every 10°F (5.5°C) change. A tire reading 800,000 Pa at 45°C will show a different pressure at 10°C even if no air has been added or lost.Normalized pressure adjusts all readings to a standard 20°C (68°F) reference, allowing you to compare measurements taken under different conditions and accurately detect true pressure changes versus temperature-induced variations.
Pressure Alerts
The system automatically monitors for abnormal conditions and flags alerts:
| Alert | Type | Description |
|---|
alertPressure | Number | Pressure alert level: 0 (No Alert), 2 (Moderate), 3 (Critical) |
alertTemp | Boolean | High temperature warning — tire is operating above safe temperature threshold |
alertBattery | Boolean | Low sensor battery — sensor may need replacement soon |
Pressure Thresholds
Pressure events include the configured thresholds used for alert detection:
| Threshold | Description |
|---|
nominalPressure | Target pressure for the tire |
lowPressureWarningThr | Threshold below which a moderate alert is triggered |
lowPressureAlertThr | Threshold below which a critical alert is triggered |
highTemperatureThr | Temperature threshold above which a temperature alert is triggered |
Event Data
Each pressure event captures a snapshot of all tire pressures at a specific moment:
| Field | Description |
|---|
eventDate | Timestamp of the pressure reading (UTC) |
speedKph | Vehicle speed in km/h at the time of the reading |
tires | Array of tire data with position, pressure, temperature, and alerts |
Pressure readings are typically captured while the vehicle is in motion. The speedKph field helps you understand the operating conditions when the measurement was taken.
Tire Position
Each tire is identified by its position on the vehicle:
| Field | Description |
|---|
axleNumber | Axle number starting from 1 (front axle) |
tireCount | Total number of tires on that axle |
tireNumber | The number of the tire on the axle, starting from 1 on the right side when facing forward. |
positionIdentifier | String representation (e.g., “1L”, “2R1”, “2R2”) |
| Field | Description |
|---|
wheelSensorId | Unique identifier of the TPMS sensor |
status | Current status of the sensor |
Use Cases
Fleet-wide Pressure Monitoring
Retrieve the latest pressure data for all vehicles to identify those requiring attention:
curl --request GET \
--url 'https://public-api.masternautconnect.com/public/v1/customer/{customerId}/asset/tire?inspectionTypes=TIRE_PRESSURE' \
--header 'Authorization: Bearer <your-api-token>'
Pressure Trend Analysis
Retrieve historical pressure data to analyze trends and detect slow leaks:
curl --request GET \
--url 'https://public-api.masternautconnect.com/public/v1/customer/{customerId}/asset/{assetId}/tire/pressure/history?startDate=2025-01-01&endDate=2025-01-31' \
--header 'Authorization: Bearer <your-api-token>'
Identifying Vehicles with Pressure Issues
Filter the latest tire data to find vehicles updated since a specific date, then check for pressure alerts in the response:
curl --request GET \
--url 'https://public-api.masternautconnect.com/public/v1/customer/{customerId}/asset/tire?inspectionTypes=TIRE_PRESSURE&sinceDate=2025-01-15T00:00:00Z' \
--header 'Authorization: Bearer <your-api-token>'
