275/55R20 tire size
275mm wide with a 55% aspect ratio on a 20-inch wheel — 31.9 inches tall overall. Below: what it measures, what it swaps with, and which trucks run it from the factory.
Trucks that come with 275/55R20
| Truck | Years | Trims |
|---|---|---|
| Ford F-150 | 2015–2020 | Lariat, King Ranch, Platinum |
| Ford F-150 | 2009–2014 | Platinum, King Ranch |
| Chevrolet Silverado 1500 | 2014–2018 | LTZ, High Country |
| Chevrolet Silverado 1500 | 2007–2013 | LTZ |
| Ram 1500 | 2019–2025 | Laramie, Limited 20" |
Sizes that swap with 275/55R20
Within 3% of the original diameter — close enough to fit without a recalibration or clearance work on most trucks.
| Size | Diameter | Difference | Width |
|---|---|---|---|
| 32x11.50R17 | 32.00" | +0.09" (+0.3%) | 11.5" |
| 305/50R20 | 32.01" | +0.10" (+0.3%) | 12.0" |
| 235/80R17 | 31.80" | -0.11" (-0.3%) | 9.3" |
| 255/70R18 | 32.06" | +0.15" (+0.5%) | 10.0" |
| 255/75R17 | 32.06" | +0.15" (+0.5%) | 10.0" |
| 275/65R18 | 32.07" | +0.17" (+0.5%) | 10.8" |
| 275/45R22 | 31.74" | -0.17" (-0.5%) | 10.8" |
| 285/45R22 | 32.10" | +0.19" (+0.6%) | 11.2" |
Plus and minus sizing
Same overall height on a different wheel. Going down a wheel size buys sidewall for off-road; going up is usually about looks. Gearing and speedometer stay put either way.
Compare 275/55R20 against your current size
Tire size comparison
Diameter change, speedometer error, and whether it will rub.
31.9" tall · 10.8" wide ·
32.0" tall · 11.5" wide
Slightly larger than stock. Most owners run this without trimming, though full lock on a rough surface may touch the mud flap.
- Sits 0.05" higher at the axle and needs 0.05" more clearance at the top of the wheel well.
- 0.67" wider overall, so roughly 0.34" more on each side unless you change wheel offset.
Reading this size
275/55R20 breaks down as 275mm section width, an aspect ratio of 55 (the sidewall is 55% of the width, so 5.95 inches), and a 20-inch wheel. Overall diameter is the wheel plus two sidewalls: 20 + 5.95 + 5.95 = 31.91 inches.
That last figure is the one that matters when you change size. The speedometer, odometer, transmission shift points and stability control all assume the factory diameter, so staying within a few percent keeps everything calibrated. Width matters for clearance rather than gearing — it decides whether the tire touches the suspension at full lock.
Common questions
How tall is a 275/55R20 tire?
31.91 inches in overall diameter, with a 5.95-inch sidewall on a 20-inch wheel. Section width is 10.83 inches (275mm), and it turns about 632 times per mile. Real tires vary from the nominal figure by up to half an inch depending on brand and tread.
What is equivalent to a 275/55R20?
The closest common size is 32x11.50R17 at 32.00 inches — +0.3% different. Anything within about 3% of the original diameter swaps on without upsetting the speedometer badly or needing a tune.
Will 275/55R20 fit my truck?
It is a factory size on the Ford F-150, Chevrolet Silverado 1500, Ram 1500, so it fits those directly. On any other truck what matters is how far it is from the size fitted now — use the calculator on this page to check diameter change, speedometer error and rubbing risk against your current size.
Does going to 275/55R20 affect my speedometer?
Only if the overall diameter changes. The speedometer counts wheel rotations and multiplies by the factory tire circumference, so a larger tire makes the truck travel further per rotation than the gauge assumes and the display reads low. Around 3% is where transmission shift points and stability control calibration start to matter, and most modern trucks can be recalibrated for the new size.