This size stands for a tire with an 11-inch section width, radial construction, and a 22.5-inch rim diameter — the dominant commercial truck spec in North America.
A semi truck’s sidewall numbers are cryptic until you understand what the 11R22.5 tire size means. The “11” is the section width in inches, “R” stands for radial construction, and “22.5” is the rim diameter.
What The Numbers On 11R22.5 Actually Mean
The “11” refers to the nominal section width — the distance from sidewall to sidewall at the widest point, not the tread width or overall diameter. That translates to about 279 millimeters. The “R” confirms radial construction, where the body plies run perpendicular to the tread. The “22.5” is the rim diameter in inches.
Unlike metric sizes such as 295/75R22.5, the 11R22.5 does not state an aspect ratio explicitly. It defaults to a profile of roughly 90 to 95 percent, meaning the sidewall height is about 90 to 95 percent of the section width. A 90 to 95 percent aspect ratio means the sidewall is nearly as tall as the section width is wide, giving the tire a tall, rounded profile that provides good load capacity and a smoother ride over uneven surfaces compared to lower-profile designs. That works out to a sidewall height of approximately 9.3 to 9.68 inches and an overall diameter of about 41.5 to 41.86 inches — noticeably taller than low-profile 22.5-inch alternatives.
Load Range G is common for this size, supporting up to 6,175 pounds at 105 PSI in single configurations. Load Range G tires have a 14-ply rating and handle the heaviest Class 8 loads. A typical load index and speed symbol is 148/145K, which covers heavy drive-axle applications. Never exceed the sidewall’s stated maximum pressure or the OEM placard’s cold inflation spec.
Which Trucks Use 11R22.5 Tires?
This size is the backbone of North American commercial trucking. You will find 11R22.5 tires on Class 8 tractors and trailers in long-haul, regional, and vocational service. They also appear on the front axles of Class 6 and Class 7 trucks and on certain large motorhomes. The size works on steer, drive, and trailer positions, which makes it a fleet-friendly standard.
The required rim diameter is 22.5 inches with a standard rim width of 8.25 inches. Always check the OEM placard on the driver’s door jamb or cab B-pillar for the exact size, load range, and cold inflation pressure specified by the manufacturer. Using a different size or load range than specified can affect handling, braking, and tire life.
11R22.5 vs Low-Profile Sizes: Key Differences
The closest metric relative to the 11R22.5 is the 295/75R22.5, but the two are not interchangeable on the same axle. The 11R22.5 is taller because its default aspect ratio sits around 90 to 95 percent versus the 75 percent of the metric size. The table below shows how they compare.
| Parameter | 11R22.5 | 295/75R22.5 |
|---|---|---|
| Section Width | ~11 in (279 mm) | ~11.6 in (295 mm) |
| Aspect Ratio | ~90–95% (default) | 75% |
| Sidewall Height | ~9.3–9.68 in | ~8.7 in |
| Overall Diameter | ~41.5–41.86 in | ~40.2 in |
| Ride Height | Taller | ~1.5 in lower |
| Speed at Same RPM | ~3 mph faster than 10R22.5 | Lower than 11R22.5 |
| Common Positions | Steer, Drive, Trailer | Drive, Trailer |
The 275/80R22.5 is another common low-profile size — shorter and wider than the 11R22.5. Mixing 11R22.5 tires with any low-profile 22.5 size on the same axle causes drivetrain stress and uneven wear due to differences in diameter and sidewall height. Because the 11R22.5 has a larger overall diameter, a truck running these tires will travel about 3 mph faster at the same engine RPM compared to a truck with 10R22.5 tires — a factor to account for when replacing older sizes. Per Bridgestone’s commercial tire guide, always confirm sizing and load data against the latest TRA Yearbook rather than third-party converters.
If you are evaluating replacement options, it helps to compare current 11R 22.5 tire recommendations from trusted sources before making a purchase decision.
FAQs
Does a bigger section width mean a wider tread?
Not directly. Section width measures the widest point of the tire casing, sidewall to sidewall. Tread width is narrower and varies by tire design and manufacturer, so two 11R22.5 tires can have different contact patches even though their section widths are identical.
Can I replace 295/75R22.5 tires with 11R22.5?
Not on the same axle. The 11R22.5 is about 1.5 inches taller in overall diameter, which changes ride height, speedometer readings, and drivetrain geometry. If you switch axle groups, replace all tires on that axle with the same size and confirm the rim width is 8.25 inches.
Why does the 11R22.5 remain popular when metric sizes exist?
It offers a taller sidewall and greater load-carrying volume per revolution, which can improve fuel economy and wear life on long-haul routes. Fleet shops also stock it widely across North America, making replacements easy to source on the road.
References & Sources
- Bridgestone Commercial. “Semi Truck Tire Size Guide.” Official resource covering 11R22.5 sizing, load ranges, and application guidance.