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255/70R18 vs 285/45R22 tire size comparison

255/70R18285/45R22

285/45R22 is 1 mm (0.14%) taller than 255/70R18 and 1.2 in wider. They fit different wheels: 255/70R18 an 18-inch wheel and 285/45R22 a 22-inch wheel.

255/70R18 and 285/45R22 side by side

0.0 in / +0.14%255/70R18: 32.1 in tall, solid line285/45R22: 32.1 in tall, dashed line255/70R18Width 10.0 in (255 mm)Sidewall 7.0 in (179 mm)285/45R22Width 11.2 in (285 mm)Sidewall 5.0 in (128 mm)
255/70R18 is drawn with a solid line and 285/45R22 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 285/45R22, with the difference (285/45R22 minus 255/70R18)
Measurement255/70R18285/45R22DifferenceDifference %
Section width10.0 in (255 mm)11.2 in (285 mm)+1.2 in (+30 mm)+11.76%
Sidewall height7.0 in (179 mm)5.0 in (128 mm)-2.0 in (-51 mm)-28.15%
Wheel (rim) diameter18.0 in (457 mm)22.0 in (559 mm)+4.0 in (+102 mm)+22.22%
Overall diameter32.1 in (814 mm)32.1 in (815 mm)0.0 in (+1 mm)+0.14%
Circumference100.7 in (2558 mm)100.8 in (2561 mm)+0.1 in (+3 mm)+0.14%
Revolutions per mile629628-1-0.13%

Differences are 285/45R22 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 0.14%, 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 285/45R22 is about 60.1 mph. When it reads 60 mph on a vehicle built for 285/45R22, the actual speed on 255/70R18 is about 59.9 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 285/45R22
Speedometer readsActual on 285/45R22 (built for 255/70R18)Actual on 255/70R18 (built for 285/45R22)
20 mph20.0 mph20.0 mph
30 mph30.0 mph30.0 mph
40 mph40.1 mph39.9 mph
50 mph50.1 mph49.9 mph
60 mph60.1 mph59.9 mph
70 mph70.1 mph69.9 mph
80 mph80.1 mph79.9 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.

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Shop for 255/70R18 or 285/45R22 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 285/45R22

Side-by-side dimensions and speedometer difference for sizes close to 285/45R22 in overall diameter.

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