Bridgestone Team
Having the correct semi-truck or 18-wheeler tire size is vital in the operation of any size fleet of trucks. Properly operating tires impact the bottom line regarding the amount of time the trucks can be on the road and the safety of your operators and others on the road. Having the wrong semi-truck tire size can mean that general wear and tear happens faster. The size matters when understanding how the placement of each tire. More maintenance or less time on the road means your payload is not being delivered.
Over the last few years, the most common truck tire sizes include but are not limited to 295/75R22.5, 275/70R22.5, and 225/70R19.5. While these cover average truck tire sizes and the list is good information to have, it is not ultimately helpful if you don’t understand what these numbers mean to you and your trucks.
If we take that first size, 295/75R22.5 and explain how semi-truck tires are sized, those numbers break down into several informative categories.
Size(Metric)
| Inches(approx.) | Application | Emerging Tech/Type | Typical Load Range(Single/Dual, lbs) | Recommended PSI | Notes |
295/75R22.5 | 11R22.5 | Drive/Trailer, Long Haul | Standard, LRR option | 6175/5675 | 110-120 | Most common; LRR, SmartWay available |
275/80R22.5 | 11R22.5 | Steer, Drive | Standard | 6175/5840 | 110-120 | Popular for long haul |
285/75R24.5 | 11R24.5 | Drive, Heavy Haul | Standard | 6610/6005 | 110-120 | Higher load, taller profile |
255/70R22.5 | 10R22.5 | Trailer, Regional | LRR | 5205/4806 | 100-110 | Regional and P&D |
Check the sub-sections below for practical tips on measuring.
The first number in the series is your tire’s width. Semi-truck tire width can be listed in either inches or millimeters. A 295-inch tire would be huge, so you can safely bet it’s in millimeters. Having the correct width is key—it’s literally where the rubber meets the road.
How to Measure: Use calipers or a tape measure across the widest part of the tire (sidewall to sidewall)—not just the tread.
Contact Patch & Traction: Wider tires create a bigger contact patch, improving traction, but often bump up rolling resistance and fuel use.
Clearance Checks: Make sure there’s enough space at the axle and fender—too much width may cause rubbing when loaded or during suspension travel.
The second number (e.g., 75) after the slash is the aspect ratio. It represents the percentage of the length of height to width. This number is an important sizing calculation in tire fitting, and along with rim diameter will help you determine your best tire and wheel combinations.
Low-Profile Pros: Better handling, improved stability, and lower center of gravity.
Standard/Tall Pros: More cushioning (ride comfort), potentially longer tire life, and often better for rough roads.
Cost Comparison (Example): Fleets using 70-series instead of 75-series tires can see up to a 5% boost in MPG from lower rolling resistance, though lower profiles may cost 3–8% more upfront.
In this example, the letter R stands for radial (this notates that the steel belts inside are running 90-degrees from the direction the tire is facing). If you see a dash, then the tire is bias-ply (this notates that the nylon belts running anywhere from 30 to 45-degrees from the direction the tire is facing). Much less common are B for bias belt and D for diagonal.
The number after “R” tells you what wheel diameter (in inches) fits the tire—such as “22.5” for a 22.5-inch rim. This isn’t the full tire’s height.
Plus-sizing/Minus-sizing: Going up in rim diameter (plus-sizing) with a lower aspect ratio boosts handling but may impact ride comfort and affect your speedometer. Minus-sizing does the opposite, with more sidewall height.
Compatibility Checks: Ensure rim diameter matches brake, offset, and clearance—never force-fit a mismatched tire and wheel.
You’ll spot two extra numbers on the sidewall: load index tells you how much weight a tire can safely carry. For example, a tire labeled 89 supports 1,279 pounds, while 88 means 1,235
How to Calculate: Multiply the load index by the number of tires per axle to check your total axle capacity.
You will see a speed rating letter at the end of the string. This indicates how fast the tire can go under its maximum load. A tire can go faster than this number at a lower load, but typically the tires can withstand a higher speed than the speed limits you will encounter.
Combined Effects: Safe speed depends on heat buildup, tire load, and inflation—overloaded or underinflated tires are more likely to fail, even below their speed rating.
Fleet Tip: Many fleets boost fuel efficiency by spec’ing L-rated tires, matching governor-limited highway speeds to the tire’s safe operating range.
The right tire diameter, width, and tread have a real impact on rolling resistance, aerodynamics, and handling. Taller tires can lower engine RPMs at cruising speeds, saving fuel, while wider tires improve traction but may slightly reduce miles per gallon.
Case Study: One regional fleet switched from standard duals (295/75R22.5) to wide-base singles (445/50R22.5) and reported up to 4–6% fuel savings and 370 lbs. less weight per axle, freeing up payload.
Tread Design: Low-rolling-resistance and SmartWay-verified tread options can maximize fuel economy while keeping ride and handling safe and predictable.
Independent and Bridgestone studies show that good tire sizing and correct inflation aren’t just small details—they drive real, long-term savings and keep fleets focused on what really matters: strong margins, safe drivers, and deliveries made on time.
There are many tires to choose from, but finding the right tire for your needs is simple with our Tire Selector tool.