TruckTally

255/70R17 tire size

255mm wide with a 70% aspect ratio on a 17-inch wheel — 31.1 inches tall overall. Below: what it measures, what it swaps with, and which trucks run it from the factory.

Overall diameter
31.06"
Section width
10.04"
255mm
Sidewall height
7.03"
Revs per mile
649
97.6" circumference

Trucks that come with 255/70R17

TruckYearsTrims
Chevrolet Silverado 15002019–2025WT, Custom 17"
Chevrolet Silverado 15002014–2018WT, LS

Sizes that swap with 255/70R17

Within 3% of the original diameter — close enough to fit without a recalibration or clearance work on most trucks.

SizeDiameterDifferenceWidth
255/65R1831.05"same height10.0"
255/55R2031.04"same height10.0"
275/65R1731.07"+0.02" (+0.1%)10.8"
31x10.50R1531.00"-0.06" (-0.2%)10.5"
275/60R1830.99"-0.06" (-0.2%)10.8"
285/40R2230.98"-0.08" (-0.3%)11.2"
275/55R1930.91"-0.15" (-0.5%)10.8"
285/50R2031.22"+0.17" (+0.5%)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 255/70R17 against your current size

Tire size comparison

Diameter change, speedometer error, and whether it will rub.

Current / stock size

31.1" tall · 10.0" wide ·

New size

31.1" tall · 10.0" wide ·

Direct fit

Diameter and width are close enough to stock that this is a bolt-on swap on an unmodified truck.

17"31.1" tall255/70R1718"31.1" tall255/65R1810.0" wide10.0" wide
Drawn to scale from the calculated sizes. Circles compare overall height and wheel diameter; the bars underneath compare section width.
Diameter change
-0.00"
-0.0% — 31.06" to 31.05"
Speedometer at 70
70.0mph actual
Reads 0.0% fast — you are going slower than it says.
Ride height
-0.00"
Change at the axle, before any lift or leveling kit.
Section width
+0.00"
10.04" to 10.04"
Revs per mile
650
+0 vs. stock (649)
Odometer drift
1000real miles
Actual distance covered per 1,000 miles shown on the odometer.
  • Within the range normally treated as a direct swap — no clearance work expected.

Reading this size

255/70R17 breaks down as 255mm section width, an aspect ratio of 70 (the sidewall is 70% of the width, so 7.03 inches), and a 17-inch wheel. Overall diameter is the wheel plus two sidewalls: 17 + 7.03 + 7.03 = 31.06 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 255/70R17 tire?

31.06 inches in overall diameter, with a 7.03-inch sidewall on a 17-inch wheel. Section width is 10.04 inches (255mm), and it turns about 649 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 255/70R17?

The closest common size is 255/65R18 at 31.05 inches — effectively identical. Anything within about 3% of the original diameter swaps on without upsetting the speedometer badly or needing a tune.

Will 255/70R17 fit my truck?

It is a factory size on the Chevrolet Silverado 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 255/70R17 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.

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