Semi Truck Tire Sizes
Trailer Tire Sizes
Trailer tires can be easy to ignore until a roadside stop or a shredded casing changes the day. Mixed trailer pools make size and condition checks even more important.
The goal is simple: know what is mounted, whether the duals match, and whether the tire is suitable for that trailer and load.
Why trailer positions are different
Trailer tires see scrub from tight turns, uneven loading, yard moves, and long parked periods. Size choice should follow the trailer spec and tire manufacturer data, not only what is available at the shop. Inside duals on trailer axles are especially vulnerable to ignored low pressure — a driver checking trailer tires in a busy yard may not reach the inner valve stem on every axle.
Dropped trailer inspection priorities
| Check | Why it matters | Tool needed |
|---|---|---|
| Pressure on inside duals | Low inside dual causes dual mismatch wear and heat buildup undetected from outside | Pressure gauge with valve extension |
| Tread depth on all positions | Parked trailers accumulate wear history without regular reporting | Tread depth gauge |
| Sidewall condition including scrub marks | Yard moves and tight turns leave marks that escalate to casing damage | Flashlight |
| Dual tread depth match | Mismatched tread depths cause one tire to drag; find mismatch before dispatch | Gauge on both tires in each dual set |
| Tire size consistency | Mixed pools can result in size substitutions that violate trailer spec | Compare sidewall markings to trailer specification |
Trailer position record
| Record | Why it helps |
|---|---|
| Tire size on each position | Catches mixed trailer-pool substitutions. |
| Tread depth across the axle | Shows mismatches before they damage dual sets. |
| Visible date code when accessible | Supports age and history review. |
| Retread status if marked | Keeps casing policy visible. |
When to flag for shop review
Flag a trailer tire for shop review when any inside dual reads more than 10 PSI below its mate, when tread depth on any position is within 2/32 inch of the removal limit, when shoulder wear appears only on the inner or outer edge (alignment or load suspect), or when any sidewall shows a bulge, cut, or separation mark. Repeated pressure loss on the same position without a confirmed cause warrants a valve and bead inspection before the next dispatch.
Size Verification Checklist
- Inspect inside duals with a light — do not guess from outside.
- Check for irregular shoulder wear on every axle.
- Measure and record tread depths across dual sets.
- Do not assume a parked trailer was recently checked.
- Flag any inside dual more than 10 PSI below its outside mate.
FAQ
What tire sizes are used on semi trailers?
The 295/75R22.5 and 11R22.5 are among the most widely used trailer tire sizes in North American highway fleets. The 285/75R24.5 appears on some trailer types with 24.5-inch rim equipment. Trailer tire sizes should match the trailer manufacturer's specification. Mixed trailer pools often carry multiple sizes, which requires careful matching within each dual axle position.
Do trailer tires need to match drive tires in size?
Trailer tires and tractor drive tires do not need to be the same size, but trailer tire positions must be matched within each axle and within each dual assembly. A size mismatch in a trailer dual set causes scrub, heat, and uneven wear on both tires. Use the trailer manufacturer's specification as the basis for size selection, not what happens to be available.
How often should trailer tires be inspected?
Trailer tires need the same routine inspection as tractor tires — before every dispatch. Dropped trailers, mixed pools, and infrequent attention are common reasons trailer tires accumulate problems undetected. Check pressure, tread depth, sidewalls, and inside duals every time the trailer is prepared for service. Do not rely on the last driver's check from days or weeks earlier.
Source Notes
- Government 49 CFR 393.75 - Tires
- Industry U.S. Tire Manufacturers Association Tire Safety
- Site note TruckTireGuide.com editorial notes