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255/70R18 vs LT265/70R17 tire size comparison

255/70R18LT265/70R17

LT265/70R17 is 0.5 in (1.40%) shorter than 255/70R18 and 0.4 in wider. They fit different wheels: 255/70R18 an 18-inch wheel and LT265/70R17 a 17-inch wheel.

255/70R18 and LT265/70R17 side by side

-0.5 in / -1.40%255/70R18: 32.1 in tall, solid lineLT265/70R17: 31.6 in tall, dashed line255/70R18Width 10.0 in (255 mm)Sidewall 7.0 in (179 mm)LT265/70R17Width 10.4 in (265 mm)Sidewall 7.3 in (186 mm)
255/70R18 is drawn with a solid line and LT265/70R17 with a dashed line. In each drawing both tires are to the same scale; the tread shoulder and bead curves are simplified. The table below has the same numbers.
Dimensions of 255/70R18 and LT265/70R17, with the difference (LT265/70R17 minus 255/70R18)
Measurement255/70R18LT265/70R17DifferenceDifference %
Section width10.0 in (255 mm)10.4 in (265 mm)+0.4 in (+10 mm)+3.92%
Sidewall height7.0 in (179 mm)7.3 in (186 mm)+0.3 in (+7 mm)+3.92%
Wheel (rim) diameter18.0 in (457 mm)17.0 in (432 mm)-1.0 in (-25 mm)-5.56%
Overall diameter32.1 in (814 mm)31.6 in (803 mm)-0.5 in (-11 mm)-1.40%
Circumference100.7 in (2558 mm)99.3 in (2522 mm)-1.4 in (-36 mm)-1.40%
Revolutions per mile629638+9+1.42%

Differences are LT265/70R17 minus 255/70R18; percentages are relative to 255/70R18. These are nominal design dimensions. Real tires vary by brand, tread depth, wheel width, load and pressure.

The overall diameter differs by 1.40%, which is within the common 3% rule of thumb.

The rule of thumb keeps a replacement size within about 3% of the original overall diameter. It covers diameter only. It is not a fit, load or safety check, because width, wheel diameter, load capacity and clearance matter too. Confirm any size change with your vehicle's owner's manual or a tire professional.

Speedometer difference

When the speedometer reads 60 mph on a vehicle built for 255/70R18, the actual speed on LT265/70R17 is about 59.2 mph. When it reads 60 mph on a vehicle built for LT265/70R17, the actual speed on 255/70R18 is about 60.9 mph. These figures assume the speedometer is accurate on the original size and use nominal dimensions, so treat them as estimates.

Actual speed for a given speedometer reading, 255/70R18 against LT265/70R17
Speedometer readsActual on LT265/70R17 (built for 255/70R18)Actual on 255/70R18 (built for LT265/70R17)
20 mph19.7 mph20.3 mph
30 mph29.6 mph30.4 mph
40 mph39.4 mph40.6 mph
50 mph49.3 mph50.7 mph
60 mph59.2 mph60.9 mph
70 mph69.0 mph71.0 mph
80 mph78.9 mph81.1 mph

A common rule of thumb is to keep a replacement size within about 3% of the original overall diameter. Check the tire placard on the driver's door jamb and your owner's manual for the sizes your vehicle was built for. Confirm any size change with your vehicle's owner's manual or a tire professional.

Which vehicles use each size?

These vehicles list the size among their verified sizes, by trim. Open one to see all of its sizes.

Check it in the calculator

The calculator takes the same two sizes and shows the full comparison, or lets you swap either one for another size.

Open this comparison in the calculator

Shop for 255/70R18 or LT265/70R17 tires

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Other comparisons with 255/70R18

Side-by-side dimensions and speedometer difference for sizes close to 255/70R18 in overall diameter.

Other comparisons with LT265/70R17

Side-by-side dimensions and speedometer difference for sizes close to LT265/70R17 in overall diameter.

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