255/70R17 tire size: 31.06 in tall
Diameter, sidewall, width and revs per mile for 255/70R17, the common sizes within 3% of its diameter, and what each one does to the speedometer.
255/70R17, in short: 31.06 in (789 mm) tall and 255 mm (10.04 in) wide, with a 7.03 in (178.5 mm) sidewall, for a 17-inch wheel. Circumference is 97.56 in, so it turns about 649 times per mile (calculated from the nominal size).
Calculated from the size: sidewall = 255 × 70% = 178.50 mm; diameter = 2 × 7.028 in + 17 in; revs per mile = 63,360 ÷ (π × diameter).
Sizes within 3% of 255/70R17
12 common sizes come within ±3% of 31.06 in: 5 on the same 17-inch wheel, 3 plus-size and 4 minus-size. The last column is what the speedometer shows when the vehicle, set up for 255/70R17, is doing a true 60 mph.
| Size | Fit | Diameter | Difference | Width | Sidewall | Revs/mile (calc.) | Speedometer at a true 60 |
|---|---|---|---|---|---|---|---|
| 255/70R17 | This size | 31.06 in | - | 255 mm | 7.03 in | 649 | 60.0 mph |
| 245/75R16 | Minus 1 | 30.47 in | -1.89% | 245 mm | 7.23 in | 662 | 61.2 mph |
| 265/70R16 | Minus 1 | 30.61 in | -1.45% | 265 mm | 7.30 in | 659 | 60.9 mph |
| 265/75R16 | Minus 1 | 31.65 in | +1.91% | 265 mm | 7.82 in | 637 | 58.9 mph |
| 235/85R16 | Minus 1 | 31.73 in | +2.17% | 235 mm | 7.86 in | 636 | 58.7 mph |
| 245/70R17 | Same wheel | 30.50 in | -1.77% | 245 mm | 6.75 in | 661 | 61.1 mph |
| 265/65R17 | Same wheel | 30.56 in | -1.58% | 265 mm | 6.78 in | 660 | 61.0 mph |
| 245/75R17 | Same wheel | 31.47 in | +1.33% | 245 mm | 7.23 in | 641 | 59.2 mph |
| 265/70R17 | Same wheel | 31.61 in | +1.77% | 265 mm | 7.30 in | 638 | 59.0 mph |
| 235/80R17 | Same wheel | 31.80 in | +2.41% | 235 mm | 7.40 in | 634 | 58.6 mph |
| 265/60R18 | Plus 1 | 30.52 in | -1.72% | 265 mm | 6.26 in | 661 | 61.1 mph |
| 255/65R18 | Plus 1 | 31.05 in | -0.01% | 255 mm | 6.53 in | 650 | 60.0 mph |
| 265/65R18 | Plus 1 | 31.56 in | +1.64% | 265 mm | 6.78 in | 639 | 59.0 mph |
A taller tire makes the speedometer read low, a shorter one high. Plus-sizing keeps the diameter close by trading sidewall for wheel. Any replacement needs a load index at least as high as the vehicle's tire placard calls for, and a wheel width the tire is approved for.
255/70R17 compared
255/70R17 side by side with 265/70R17 and 275/65R18: dimension by dimension, and what the swap does to the speedometer.
255/70R17 vs 265/70R17
+1.77% diameter| 255/70R17 | 265/70R17 | Difference | |
|---|---|---|---|
| Overall diameter | 31.06 in | 31.61 in | +0.55 in (+1.8%) |
| Section width | 255 mm | 265 mm | +10 mm |
| Sidewall height | 7.03 in | 7.30 in | +0.28 in |
| Wheel diameter | 17 in | 17 in | +0 in |
| Circumference | 97.6 in | 99.3 in | +1.7 in |
| Revs per mile (calc.) | 649 | 638 | -11 |
265/70R17 is 1.8% taller than 255/70R17. At a true 60 mph the speedometer shows 59.0 mph (it reads low), and when it shows 60 you're doing 61.1 mph.
255/70R17 vs 275/65R18
+3.28% diameter| 255/70R17 | 275/65R18 | Difference | |
|---|---|---|---|
| Overall diameter | 31.06 in | 32.07 in | +1.02 in (+3.3%) |
| Section width | 255 mm | 275 mm | +20 mm |
| Sidewall height | 7.03 in | 7.04 in | +0.01 in |
| Wheel diameter | 17 in | 18 in | +1 in |
| Circumference | 97.6 in | 100.8 in | +3.2 in |
| Revs per mile (calc.) | 649 | 629 | -21 |
275/65R18 is 3.3% taller than 255/70R17. At a true 60 mph the speedometer shows 58.1 mph (it reads low), and when it shows 60 you're doing 62.0 mph.
Which vehicles come with 255/70R17
Vehicles sold in the US that have 255/70R17 as the standard size on these trims, with the page that lists it. The tire placard on the driver's door edge or post has the size, and the load and inflation, for the exact vehicle.
- Chevrolet Silverado 1500 2025 model year · WT, LTMavis Tire OE fitment page, 2025 Chevrolet Silverado 1500 WT (size flagged standard 'S')
Vehicles mostly picked from Carscoops: 2025 U.S. car sales, full-year top 25 (Car and Driver data, January 2026).
Questions about 255/70R17 tires
How tall is a 255/70R17 tire?
What is 255/70R17 in inches?
How many revolutions per mile does a 255/70R17 tire make?
What size can replace 255/70R17?
255/70R17 vs 265/70R17: what's the difference?
Which vehicles come with 255/70R17 tires?
How these numbers are worked out
- NHTSA: Tire safety, everything rides on it (reading the sidewall and the placard)
- Tire Rack: How do I calculate tire dimensions?
- Jalopnik: What the 3% rule means for your tires (April 2026)
Checked October 2026. Dimensions are nominal, calculated from the size designation. A real tire's diameter, width and revs per mile vary by brand, tread depth, rim width and load, so check the maker's spec sheet.
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