ST and LT describe different intended applications

ST — Special Trailer
Trailer applications when the size and specification match the trailer maker's requirements

ST tires are built and labeled for trailer service. Evaluate the exact load range, capacity, inflation pressure, speed rating, and wheel compatibility rather than treating every ST tire as equivalent.

LT — Light Truck
Light-truck service and only trailer applications that are specifically approved for that fitment

An LT tire may have dimensions that look close to an ST tire while carrying a different load specification or pressure requirement. Similar size does not by itself establish an acceptable substitution.

Different size or load range
A verified engineering or manufacturer-approved change

Changing diameter, width, capacity, or inflation can affect clearance, wheel rating, axle load margin, speed capability, and how the trailer sits. Verify the whole combination before buying.

Write down these numbers before shopping for replacement trailer tires

  • Original tire size and tire type specified by the trailer manufacturer
  • Trailer GVWR and each GAWR on the certification label
  • Actual loaded trailer weight when possible, including cargo, water, batteries, and accessories
  • Required tire load capacity at the specified cold inflation pressure
  • Wheel diameter, width, offset or clearance considerations, and maximum wheel pressure/load rating
  • Tire speed rating and the speeds the trailer will realistically see on U.S. highways
  • Clearance between the tire and suspension, body, neighboring tire, fender, and wheel well through suspension travel

If you are considering a switch from the original tire type

  1. 01
    Ask why you want to change

    A blowout history, unusual wear, limited local availability, or a desire for higher capacity may each have a different root cause. Fixing overload, low pressure, alignment, wheel damage, or excessive speed can matter more than changing the letters on the sidewall.

  2. 02
    Verify capacity at the actual pressure the wheel can support

    A tire's maximum capability is not useful if the wheel, valve, axle, or trailer specification cannot support the required pressure or load. Use the relevant load tables and manufacturer guidance for the exact tire.

  3. 03
    Confirm physical clearance and service rating

    Check loaded radius, section width, dual spacing when applicable, fender clearance, and speed rating. A dimension that fits while parked can still contact the trailer under load or suspension movement.

  4. 04
    Document the approved replacement specification

    Keep the tire size, cold pressure, load information, and any manufacturer approval with the trailer records so future replacements do not rely on memory or the old tire alone.

Safety check

Do not use load range as a shortcut for compatibility

A higher load-range letter does not automatically mean the tire is a better or approved fit for a particular trailer. Tire type, size, capacity, inflation, wheel limits, speed rating, and the trailer manufacturer's requirements all need to agree. If the proposed replacement differs from the original specification, confirm the change before mounting it.