How Tall Is a 275 70 R18 Tire? Exact Height, Width & Dimensions
A 275/70R18 tire is a 33-inch-class tire size often used on trucks and SUVs. By tire-size math, it measures about 33.2 inches tall, 10.8 inches wide at the section width, and 7.6 inches from rim to tread. Those numbers help you compare clearance, gearing, ride height, and speedometer accuracy before you change tire sizes.
Quick Answer
A 275/70R18 tire is about 33.2 inches tall, 10.8 inches wide, and has a 7.6-inch sidewall by calculation. Its theoretical circumference is about 104.2 inches, which equals roughly 608 revolutions per mile. Real mounted dimensions can vary by brand, tread design, load range, and wheel width.
Key Takeaways
- A 275/70R18 tire has a calculated overall diameter of about 33.2 inches, or about 842 mm.
- The “275” means the tire has a nominal section width of 275 mm, or about 10.8 inches.
- The “70” means the sidewall height is 70% of the section width, which equals about 7.6 inches.
- The “R” means radial construction, and the “18” means the tire fits an 18-inch wheel only.
- A 275/70R18 is close to a 33-inch tire, but actual tire specs can differ by model and tread depth.
- Before switching from a smaller stock tire, check clearance, load rating, wheel width, TPMS settings, and speedometer error.
At a Glance
| Time Required | 5 to 10 minutes for the math; longer if you are checking vehicle clearance. |
| Difficulty | Easy for size calculations; moderate for real-world fitment checks. |
| Tools Needed | Calculator, owner’s manual or tire placard, tire maker’s spec sheet, and a tape measure for clearance checks. |
| Cost | Free for the calculation; professional fitment checks or recalibration may cost extra. |
How Tall Is a 275/70R18 Tire?
A 275/70R18 tire is about 33.2 inches tall when you calculate the size from the tire code. In metric terms, that equals about 842 mm in theoretical overall diameter.
The word theoretical matters. Tire-size math gives you a reliable starting point, but real mounted height can vary by tire model, tread depth, load range, inflation pressure, and wheel width. Tire Rack also notes that light-truck tire diameters in size charts are typical, not guaranteed, because different tread designs and molded tread depths can change the final overall diameter.
What Does 275/70R18 Mean?
The tire code tells you the tire’s nominal width, sidewall ratio, construction type, and wheel diameter. Michelin’s tire-marking guide explains that tire sidewall numbers identify key details such as width, aspect ratio, construction, wheel diameter, load rating, and speed rating.
- 275: The nominal section width in millimeters. In inches, 275 mm equals about 10.8 inches.
- 70: The aspect ratio. The sidewall height is 70% of the section width.
- R: Radial construction, which is the common construction type for modern passenger, SUV, and light-truck tires.
- 18: The wheel diameter in inches. A 275/70R18 tire fits an 18-inch wheel only.
Note: The size code does not tell you every fitment detail. You still need the tire maker’s published spec sheet for approved rim-width range, measured diameter, tread width, load capacity, and maximum inflation pressure.
How to Calculate 275/70R18 Tire Size
You can calculate the main 275/70R18 tire dimensions with simple tire-size math:
- Section width: 275 mm ÷ 25.4 = 10.8 inches
- Sidewall height: 275 mm × 0.70 = 192.5 mm, or 7.6 inches
- Overall diameter: 18 inches + 7.6 inches + 7.6 inches = about 33.2 inches
- Circumference: 33.2 inches × 3.1416 = about 104.2 inches
- Revolutions per mile: 63,360 inches ÷ 104.2 inches = about 608
The formula works because the tire has one sidewall above the wheel and one sidewall below it. You add both sidewalls to the 18-inch wheel diameter to estimate total unloaded tire height.
A 275/70R18 calculates to about 33.2 inches tall, but many light-truck size charts place LT275/70R18 in the broader 33-inch to 33.5-inch class because real tire specs vary by design.
What Are the 275/70R18 Dimensions?
The main 275/70R18 dimensions are a 33.2-inch calculated overall diameter, 10.8-inch nominal section width, 7.6-inch sidewall height, and 18-inch wheel diameter. Use these numbers as a planning tool, not as a final fitment guarantee.
| Measurement | 275/70R18 Value | What It Means |
|---|---|---|
| Section width | 275 mm / 10.8 in | Nominal sidewall-to-sidewall width |
| Sidewall height | 192.5 mm / 7.6 in | 70% of the section width |
| Wheel diameter | 18 in / 457.2 mm | Fits an 18-inch wheel only |
| Overall diameter | 842 mm / 33.2 in | Calculated unloaded tire height |
| Circumference | 2,646 mm / 104.2 in | Theoretical distance traveled per tire revolution |
| Revolutions per mile | About 608 | Theoretical rotations over one mile |
The diameter affects ride height and gearing. The section width affects clearance near suspension parts and fenders. The sidewall height affects ride feel, impact absorption, and how much room the tire needs under load.
How Wide Is a 275/70R18 Tire?
A 275/70R18 tire has a nominal section width of 275 millimeters, or about 10.8 inches. Section width is measured from sidewall to sidewall, not across the tread blocks. Bridgestone’s tire terminology guide defines section width as the sidewall-to-sidewall measurement, excluding raised lettering.
Section Width vs. Tread Width
The 275 mm number does not guarantee the exact tread width that touches the road. Actual tread width can change by tire model, highway versus all-terrain tread design, rim width, and inflation pressure.
Use section width when you compare tire sizes. Use the tire manufacturer’s spec sheet when you need exact tread width, approved rim-width range, load capacity, measured diameter, and mounted measurements.
Is a 275/70R18 the Same as a 33-Inch Tire?
A 275/70R18 is not exactly 33.0 inches tall, but it is close enough to be considered a 33-inch-class tire. Its calculated diameter is about 33.2 inches, so many drivers compare it with 33-inch tires when checking stance, clearance, and off-road fitment.
That small difference can still matter. A tire that is 33.2 inches tall may rub where a slightly shorter tire clears, especially at full steering lock, during suspension compression, or with heavy cargo.
Warning: Do not choose a tire size by height alone. Check your owner’s manual, tire placard, approved wheel width, load index, speed rating, fender clearance, suspension clearance, and brake clearance before changing sizes. NHTSA recommends using the original tire size or another size recommended by the vehicle manufacturer.
How Do 275/70R18 Tires Affect MPG and Speedometer?
A larger tire can affect both fuel economy and speedometer accuracy, but the exact change depends on what size you replace. A 275/70R18 has a larger rolling diameter than many stock truck and SUV tires, so it may make your speedometer read lower than your actual road speed.
Use this formula:
Actual speed = indicated speed × new tire diameter ÷ old tire diameter
For example, if your vehicle originally used a 265/65R18 tire with an estimated 31.6-inch diameter, switching to a 275/70R18 with an estimated 33.2-inch diameter creates about a 5.1% diameter increase. When the speedometer shows 60 mph, your actual speed would be about 63 mph.
Fuel economy can also change after a tire-size increase. Larger or more aggressive tires may weigh more, create more rolling resistance, and alter effective gearing. Still, no single MPG-loss number applies to every vehicle. Tire model, tread pattern, inflation pressure, load, alignment, driving speed, and terrain all matter.
Pro Tip: After changing tire size, compare GPS speed with your dashboard speedometer. If the difference is large, ask a qualified shop about recalibration options for your vehicle.
[Products Worth Considering]
The Milton 555e digital tire inflator delivers fast, accurate pressure readings with a backlit display and multiple unit options, making tire inflation quick and easy. Its durable 20" EPDM rubber hose and grip‑head chuck provide reliable connection, while the ±1 PSI accuracy ensures precise inflation for cars, bikes, and trucks.
This digital tire pressure gauge combines a sturdy pistol grip inflator with a backlit 0.1 PSI display for quick, accurate readings in any lighting condition. Its 360° swivel gauge and 20" rubber hose make it easy to use and store, while the integrated inflate/deflate trigger and ¼" NPT air inlet provide fast, reliable tire maintenance.
The Milton 507KIT delivers fast, accurate tire inflation, deflation and pressure measurement with a backlit LCD gauge and 14" rubber hose. Its 3‑in‑1 design meets ANSI/ASME standards and provides readings from 0‑250 PSI with 0.1 PSI resolution. The ergonomic pistol‑grip body and brass lock‑on chuck make one‑handed operation effortless, while the auto‑off feature conserves battery life.
How Does 275/70R18 Compare to 285/70R18 and 265/65R18?
Compared with a 285/70R18, the 275/70R18 is slightly narrower and shorter. Compared with a 265/65R18, the 275/70R18 is much taller and slightly wider. Tire Rack also notes that published dimensions can vary by specific tire design, so you should check the individual tire’s spec page before buying. Tire Rack’s light-truck tire-size comparison guide is useful for checking common size categories.
| Size | Width | Sidewall | Diameter | Revs/Mile | Best Use |
|---|---|---|---|---|---|
| 265/65R18 | 10.4 in | 6.8 in | 31.6 in | About 639 | Smaller stock-style fitments |
| 275/70R18 | 10.8 in | 7.6 in | 33.2 in | About 608 | 33-inch-class truck and SUV setups |
| 285/70R18 | 11.2 in | 7.9 in | 33.7 in | About 598 | Slightly taller and wider fitments |
The jump from 265/65R18 to 275/70R18 is significant because the tire gets about 1.6 inches taller. That raises the axle and underbody by about half the diameter increase, or roughly 0.8 inch. The jump from 275/70R18 to 285/70R18 is smaller, but it still adds width and height that may affect rubbing, steering clearance, and suspension travel.
[Products Worth Considering]
The WORKPRO digital tire pressure gauge with inflator offers precise 0.1 PSI resolution and ±1% accuracy for reliable tire inflation across vehicles and inflatables. Built with heavy‑duty aluminum alloy, brass, and rubber, it resists rust and drops while delivering deflation, inflation, and pressure checking functions. The kit includes valve caps, adapters, a twist‑on chuck, screwdriver, nozzles, needle, seal tape, and a storage bag with batteries, making it a versatile, portable solution for on‑the‑go tire maintenance.
The GERCHWAY tire inflator combines a durable rubber‑protected gauge with a 360° swivel air chuck for hands‑free operation and reliable sealing on any valve. Its 100 PSI range delivers ±2 PSI accuracy, making it ideal for most passenger and light‑truck tires. The battery‑free design ensures you can measure, inflate, or deflate without worrying about power loss, while the universal ¼ NPT connection fits any standard compressor.
Will 275/70R18 Tires Fit My Vehicle?
A 275/70R18 tire may fit many trucks and SUVs, but fitment depends on the exact vehicle, trim, wheel offset, suspension height, and tire model. You should not assume it fits just because another owner runs the same size.
Before buying, check these points:
- Factory tire size: Compare the new diameter with the size on your tire placard or owner’s manual.
- Load index or load range: Match or exceed the vehicle manufacturer’s required load capacity.
- Speed rating: Use a rating that meets your vehicle’s requirements.
- Wheel width: Confirm your wheel falls within the tire manufacturer’s approved rim-width range.
- Clearance: Check the fender liner, upper control arm, sway bar, mud flaps, and bumper area.
- Full-lock turning: Test left and right steering clearance after installation.
- Suspension compression: Leave room for bumps, cargo, towing tongue weight, and off-road articulation.
- TPMS and speedometer: Recheck pressure settings and speed readings after the size change.
NHTSA’s tire safety guide recommends buying the same tire size listed in the owner’s manual or Tire and Loading Information Label unless the vehicle manufacturer recommends another size. If you have any doubt, ask a qualified tire dealer or installer to confirm the correct size, load capacity, pressure, and clearance for your vehicle.
[Products Worth Considering]
ALL-TERRAIN TIRE FOR LIGHT TRUCKS – Engineered for dependable performance on and off the road, this LT275/70R18 all-terrain tire delivers strong traction, stability, and ride comfort for light trucks.
Designed for use on light trucks and SUVs
Frequently Asked Questions
How tall is a 275/70R18 tire in inches?
A 275/70R18 tire is about 33.2 inches tall based on the standard tire-size calculation. Real tire specs can vary slightly by manufacturer, tread design, load range, air pressure, and wheel width.
Is a 275/70R18 the same as a 33-inch tire?
It is very close. A 275/70R18 calculates to about 33.2 inches tall, so it fits the 33-inch tire class. It is not exactly 33.0 inches, and actual tire measurements can vary by model.
Is a 275/70R18 a 35-inch tire?
No. A 275/70R18 is about 33.2 inches tall, so it is roughly 1.8 inches shorter than a true 35-inch tire. If you want a 35-inch tire, you need a different size.
Is a 275 tire equal to a 33-inch tire?
Not always. The number 275 only tells you the nominal section width in millimeters. You also need the aspect ratio and wheel diameter. A 275/70R18 is about 33.2 inches tall, but other 275-size tires can be shorter or taller.
What does the R mean in 275/70R18?
The R means radial construction. In this size, 275 is the nominal width in millimeters, 70 is the aspect ratio, R is the construction type, and 18 is the wheel diameter in inches.
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