{
  "slug": "semi-truck-tire-pressure-and-inflation",
  "title": "Semi Truck Tire Pressure and Trailer Tire Inflation Systems",
  "description": "Where the right semi truck tire pressure comes from, why it is checked cold, and how a trailer automatic tire inflation system adds air to a tire.",
  "track": "maintenance",
  "kind": "article",
  "isRegulatoryAdjacent": false,
  "publishedAt": "2026-10-22",
  "cfr": [],
  "related": [
    "semi-truck-and-trailer-tires",
    "truck-tire-tread-depth-and-condition",
    "wheel-seal-leaks-and-replacement",
    "recording-a-tire-and-wheel-service",
    "semi-trailer-maintenance",
    "trailer-wheel-end-maintenance"
  ],
  "topics": [
    "tires_wheels"
  ],
  "nextStep": {
    "kind": "related",
    "target": "truck-tire-tread-depth-and-condition",
    "text": "See how tread depth and tire condition are checked"
  },
  "sources": {
    "citations": [],
    "bcpRole": "Blue Collar Parts records the work and sends the report to your customer. It does not perform, certify or approve inspections.",
    "reviewed": "2026-10-22",
    "reviewedEdition": null,
    "reviewedText": "Reviewed 2026-10-22"
  },
  "url": "https://shopbluecollarparts.com/kb/semi-truck-tire-pressure-and-inflation",
  "markdownUrl": "https://shopbluecollarparts.com/kb/semi-truck-tire-pressure-and-inflation.md",
  "body": "**There is no single right pressure for a semi truck tire.** The pressure a tire should run at depends on the tire's size and load range and on the load it carries at that position, single or dual. The tire manufacturer publishes it in load and inflation tables. Look the pressure up in those tables, for the tire on the vehicle. This page explains where to find them, how to check pressure, and how trailer tire inflation systems work.\n\n## What pressure should a semi truck tire run at?\n\nStart from the tire manufacturer's load and inflation tables for that tire. They pair a load per tire with the cold inflation pressure that carries it, for single and for dual fitments. Every tire manufacturer publishes tables for its own tires. Two examples, both as published by the manufacturer:\n\n- Goodyear, *Goodyear Commercial Tires and Retreads Engineering Data Book* (2023), linked from Goodyear's [commercial tire resources page](https://www.goodyeartrucktires.com/en_US/support/resources.html).\n- Bridgestone, *Truck Tire Load & Inflation Tables*, linked from Bridgestone's [load and inflation tables page](https://commercial.bridgestone.com/en-us/resource-center/load-and-inflation-tables).\n\nUse the tables for the tire actually mounted, from its own manufacturer. Look the values up there rather than copying them from another tire. The sidewall is marked with the tire's maximum load and the pressure that goes with that maximum, which is not necessarily the pressure for the load the tire carries in service. Many customers set their own target pressures by position from these tables. Ask the customer for their targets, and record which target the work was done to.\n\n## Why is tire pressure checked cold?\n\nLoad and inflation tables give cold inflation pressures. A tire that has just been run is warmer, and its pressure reads higher than it will once it cools. Check pressure before the vehicle runs, or after it has stood long enough to cool. The tire manufacturer's guidance says what counts as cold and what to do with a tire that can only be checked warm. Record whether each reading was taken cold.\n\nA gauge reading is only as good as the gauge. Record which gauge was used if the customer asks for it, and check it against a reference gauge.\n\n## Which tires are hard to check?\n\nInner duals are harder to check, because the valve sits behind the outer wheel. Valve extensions or hoses bring the inner valve out where a gauge can reach it. Their condition, along with the valve stems and caps, is part of the check. A tire that keeps losing air between checks has a leak to find: at the valve, the bead, the wheel or the tread.\n\n## How does a trailer tire inflation system work?\n\nA trailer tire inflation system, also called an automatic tire inflation system, takes air from the trailer's air supply, regulates it to a set pressure, and delivers it to each tire while the trailer runs. At category level the parts are:\n\n- **a supply and a regulator**, which take air from the trailer's air system and set the pressure the system feeds to;\n- **a path to each wheel.** Many systems route air through the axle to a rotary union at the hub cap. Others run lines outside the axle;\n- **hoses from the hub cap to each tire's valve**, on many systems with check valves that keep one tire's leak from draining the others;\n- **an indicator**, usually a lamp the driver can see, that shows when the system is feeding air to a tire.\n\nSome systems only add air. Others can also let air out of a tire that is over its set pressure. A tire pressure monitoring system is different again: it reports pressure but does not add air.\n\nEach system's maker publishes how to set, check and service it. Follow that documentation for the system on the trailer.\n\n## What an inflation system does not do\n\nAn automatic inflation system keeps a slowly leaking tire supplied with air. It does not repair the leak, and it does not replace checking the tires. A lit indicator generally means the system is feeding air, which points to a leak in a tire, valve, hose or fitting. That leak still has to be found. The system's maker documents what its indicator means. Record the regulator setting against the customer's target pressure, the indicator's state, and the condition of the hoses and hub cap fittings.\n\n## Industry guidance\n\nThe Technology & Maintenance Council (TMC) of the American Trucking Associations publishes recommended practices for fleets. RP 235, *Guidelines for Tire Inflation Pressure Maintenance*, covers this topic. Use the current revision.\n\n## What the record should show\n\nFor each position: the pressure as found, the pressure as left, whether it was checked cold, and the target pressure and where it came from. For an inflation system: what was checked, the setting, and any repair. See [recording a tire and wheel service](/kb/recording-a-tire-and-wheel-service).\n\n## Log the work in Blue Collar Parts\n\nA technician who checks pressures or services an inflation system can log the work in Blue Collar Parts and send the record to their customer, who confirms it. [Learn what Blue Collar Parts is](/kb/what-is-blue-collar-parts).\n\n---\n\n*This page describes tire inflation in general terms. It is not a service manual and does not establish regulatory compliance. Use the tire manufacturer's current load and inflation tables and the inflation system maker's documentation for specifications and procedures.*",
  "license": "CC BY 4.0",
  "licenseUrl": "https://creativecommons.org/licenses/by/4.0/"
}