A 275/55R20 tire size measures about 31.9 inches tall and 10.8 inches wide, and it fits a 20-inch wheel. It has a 100.2-inch circumference and makes about 632 revolutions per mile.
This guide covers the 275/55R20 tire dimensions, speedometer effects, close size alternatives, and what to check before you buy.
What Does 275/55R20 Tire Size Mean?
How to Read the 275/55R20 Tire Size Code
- 275 is the section width in millimeters (10.8 inches).
- 55 is the aspect ratio. The sidewall height equals 55% of the width.
- R means radial construction.
- 20 is the rim diameter in inches.
275/55R20 vs LT275/55R20
A plain 275/55R20 is usually a passenger or P-metric tire. An LT275/55R20 is a light truck tire. It has stronger sidewalls and a higher load range, often Load Range E.
The load index also changes. A 113 load index carries up to 2,535 lbs per tire. A 117 carries 2,833 lbs. A 120 carries 3,086 lbs.
The speed rating matters too. T means up to 118 mph. H means 130 mph. V means 149 mph.
Where to Find Your Tire Size
Check the driver’s door jamb placard. You can also read the sidewall of your current tire. Use the owner’s manual if both are hard to read.
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275/55R20 Tire Size in Inches
| Size | Diameter | Change | Within 3%? |
|---|---|---|---|
| 225/40R19 | 26.1 in | about -1.2% | Yes |
| 245/40R19 | 26.7 in | about +1.2% | Yes |
| 235/45R19 | 27.3 in | about +3.4% | No |
| 235/35R19 | 25.5 in | about -3.5% | No |
| 235/40R20 | 27.4 in | about +3.8% | No |
The small gap in sidewall height (5.9 vs 6.0) comes from rounding. Brands also vary slightly in actual measured size.
How to Calculate 275/55R20 in Inches
You can check the numbers yourself in three steps.
- Width in inches: 275 ÷ 25.4 = 10.83 in
- Sidewall height: (275 × 0.55) ÷ 25.4 = 5.95 in
- Overall diameter: (2 × 5.95) + 20 = 31.9 in
For revolutions per mile, divide 63,360 inches by the 100.2-inch circumference. The result is about 632.
Best Wheel Width for 275/55R20 Tires
The approved range is 7.5 to 9.5 inches. A width near 8.0 to 9.0 inches usually gives the most even tread contact patch. A very narrow wheel can pinch the tire. A very wide one can stretch the sidewall and hurt handling.
More Post: 235/65R17 Tire Size
275/55R20 Alternative Tire Sizes
275/55R20 vs 275/60R20
Both tires are 275 mm wide. The 275/60R20 has a taller sidewall of about 6.5 inches. Its overall diameter is about 33 inches, which is 1.1 inches taller.
The 275/60R20 gives a softer ride and a bit more ground clearance. The 275/55R20 gives sharper steering and better stability on pavement.
275/55R20 vs 285/55R20
The 285/55R20 is 10 mm wider. Its diameter is about 32.3 inches, roughly 0.4 inch taller. It adds a wider footprint for traction. It also adds a little rolling resistance.
Check wheel-well clearance before you switch. A wider tire can rub at full steering lock.
Speedometer Error After Changing Tire Size
Your speedometer counts wheel turns. A taller tire covers more ground per turn. So the dash reads lower than your real speed.
Here is the math for a 33-inch tire swapped in for a 31.9-inch tire:
- 33 ÷ 31.9 = 1.034, which is about 3.4% taller
- A 60 mph dash reading becomes about 62 mph in real speed
- A 70 mph reading becomes about 72 mph
A smaller tire does the opposite. The dash reads higher than your real speed. A speedometer recalibration can fix either case.
More Post: 275/65R18 Tire Size
Vehicles & Best Tires for 275/55R20 Tires
What Vehicles Use 275/55R20 Tires?
This size shows up mostly on full-size pickups and SUVs with 20-inch wheels. Many GM, Ford, and Ram trucks have used it on certain trims and years. An example is the GMC Yukon XL 1500.
Fitment changes by trim, model year, and wheel option. Always confirm with your door jamb placard first.
Best Tire Types for 275/55R20
Match the tire to how you drive.
- All-season or highway tires: Best for daily commuting, quiet ride, and fuel savings.
- All-terrain tires: Best for gravel roads, light off-road trips, and mixed driving. Look for the 3-Peak Mountain Snowflake mark if you drive in snow.
- Mud-terrain tires: Best for deep mud and rocks. Expect more road noise and faster wear.
- Winter tires: Best for ice and heavy snow.
275/55R20 Tire Price and Buying Checklist
Most listings fall between about $150 and $350 per tire. Mud-terrain models can go past $400. Warranties commonly run from 40,000 to 80,000 miles.
Check these before you buy:
- Load index and load range for towing or hauling
- Speed rating
- Treadwear warranty miles
- Winter rating if you need it
- Mounting, balancing, and TPMS costs
More Post: 275/60R20 Tire Size
FAQ’s About 275/55R20 Tire Size
What are the exact dimensions of a 275/55R20 tire in inches?
A 275/55R20 tire is about 31.9 inches tall and 10.8 inches wide. The sidewall is about 5.9 to 6.0 inches. The circumference is 100.2 inches.
How does 275/55R20 affect speedometer accuracy?
It affects the speedometer only if your old tire had a different diameter. A taller tire makes the dash read slower than your real speed. A shorter tire makes it read faster. Each 1% change in diameter shifts the reading by about 1%.
Is a 275/55R20 tire the same as a 33-inch tire?
No. The 275/55R20 is about 31.9 inches tall. A true 33-inch tire is about 1.1 inches taller.
How does 275/55R20 compare to 285/55R20 in size and performance?
The 285/55R20 is 10 mm wider and about 0.4 inch taller. It gives a bigger contact patch and more traction. The 275/55R20 is lighter and usually better for fuel economy.
How does the 275/55R20 tire size affect fuel economy and power?
A 275/55R20 has lower rolling resistance than a taller, wider tire. That helps fuel economy a little. Bigger and heavier tires can cost a bit of mpg and acceleration. Aggressive mud-terrain tread adds even more drag.
I’m Richard Hayes, a content researcher and writer at TireMeasurements.com, specializing in measurements, tire measurements, tire sizing, wheel fitment, and related automotive topics.
