Every tire wears its full specification on its sidewall. Read it once and you can order without guessing. Commercial truck sizes come in two formats — 11R22.5 and 295/75R22.5 — and both are simpler than they look.
Standard sizes: 11R22.5
- 11 — section width. Width in inches, sidewall to sidewall.
- R — radial construction. Every modern highway truck tire is a radial.
- 22.5 — rim diameter, in inches. Tubeless truck wheels come in 22.5-inch and 24.5-inch, and that half inch never interchanges.
Metric sizes: 295/75R22.5
- 295 — section width in millimeters, nominal. Major-brand product pages print the measured width.
- 75 — aspect ratio. Sidewall height as a percentage of width — the low-profile truck tire.
- R22.5 — radial, on a 22.5-inch rim.
Ply rating and load range
Truck tires are rated 14 ply (Load Range G) or 16 ply (Load Range H). Modern radials don't literally carry 14 fabric plies — the number is a strength equivalent. H carries more weight at a higher cold inflation pressure. Match the load range to the heaviest axle load you run; every spec table lists max load single, max load dual and max pressure.
The service description: 146/143 L
After the size comes a pair like 146/143 L. The first number is the load index mounted single (146 = 6,610 lbs); the second applies in duals (143 = 6,005 lbs each). The letter is the speed symbol: L = 75 mph, M = 81 mph — matched to legal truck speeds. More in load index and speed rating explained.
Why you keep one size on an axle
11R22.5 and 295/75R22.5 both bolt to a 22.5-inch wheel and both run linehaul, but they are not interchangeable. Across the tires we carry, a 295/75R22.5 stands roughly an inch shorter in overall diameter and turns more revolutions per mile. Same story one rim size up: 285/75R24.5 stands about two inches shorter than 11R24.5.
- Duals share load by diameter. Put a taller tire beside a shorter one and it carries the pair, runs hot and wears irregularly. Dual mates want the same size and tread depth.
- Tandem drive axles fight each other. Different rolling radii front to rear wind up the inter-axle differential.
- Gauges drift. Speedometer and odometer read off rolling distance.
Positions can run different sizes if the truck was specced that way; what you don't do is mix sizes within one axle. Overall diameter, revs per mile and approved rim widths sit on every major-brand product page.
Put it to work
Know your size? Browse steer and all-position, drive and trailer tires, or the full commercial catalog. If your size isn't there, send us the stamp off the tires you're pulling — we carry all truck and trailer sizes, and quotes come back delivered, sales tax and state tire fee included.