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LT285/75R18 vs LT305/55R22 tire size comparison

LT285/75R18LT305/55R22

LT305/55R22 is 0.4 in (1.09%) taller than LT285/75R18 and 0.8 in wider. They fit different wheels: LT285/75R18 an 18-inch wheel and LT305/55R22 a 22-inch wheel.

LT285/75R18 and LT305/55R22 side by side

+0.4 in / +1.09%LT285/75R18: 34.8 in tall, solid lineLT305/55R22: 35.2 in tall, dashed lineLT285/75R18Width 11.2 in (285 mm)Sidewall 8.4 in (214 mm)LT305/55R22Width 12.0 in (305 mm)Sidewall 6.6 in (168 mm)
LT285/75R18 is drawn with a solid line and LT305/55R22 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 LT285/75R18 and LT305/55R22, with the difference (LT305/55R22 minus LT285/75R18)
MeasurementLT285/75R18LT305/55R22DifferenceDifference %
Section width11.2 in (285 mm)12.0 in (305 mm)+0.8 in (+20 mm)+7.02%
Sidewall height8.4 in (214 mm)6.6 in (168 mm)-1.8 in (-46 mm)-21.52%
Wheel (rim) diameter18.0 in (457 mm)22.0 in (559 mm)+4.0 in (+102 mm)+22.22%
Overall diameter34.8 in (885 mm)35.2 in (894 mm)+0.4 in (+9 mm)+1.09%
Circumference109.4 in (2779 mm)110.6 in (2810 mm)+1.2 in (+31 mm)+1.09%
Revolutions per mile579573-6-1.07%

Differences are LT305/55R22 minus LT285/75R18; percentages are relative to LT285/75R18. These are nominal design dimensions. Real tires vary by brand, tread depth, wheel width, load and pressure.

The overall diameter differs by 1.09%, 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 LT285/75R18, the actual speed on LT305/55R22 is about 60.7 mph. When it reads 60 mph on a vehicle built for LT305/55R22, the actual speed on LT285/75R18 is about 59.4 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, LT285/75R18 against LT305/55R22
Speedometer readsActual on LT305/55R22 (built for LT285/75R18)Actual on LT285/75R18 (built for LT305/55R22)
20 mph20.2 mph19.8 mph
30 mph30.3 mph29.7 mph
40 mph40.4 mph39.6 mph
50 mph50.5 mph49.5 mph
60 mph60.7 mph59.4 mph
70 mph70.8 mph69.2 mph
80 mph80.9 mph79.1 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 LT285/75R18 or LT305/55R22 tires

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Other comparisons with LT285/75R18

Side-by-side dimensions and speedometer difference for sizes close to LT285/75R18 in overall diameter.

Other comparisons with LT305/55R22

Side-by-side dimensions and speedometer difference for sizes close to LT305/55R22 in overall diameter.

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