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245/75R17 vs 265/55R20 tire size comparison

245/75R17265/55R20

265/55R20 is 1 mm (0.03%) taller than 245/75R17 and 0.8 in wider. They fit different wheels: 245/75R17 a 17-inch wheel and 265/55R20 a 20-inch wheel.

245/75R17 and 265/55R20 side by side

0.0 in / +0.03%245/75R17: 31.5 in tall, solid line265/55R20: 31.5 in tall, dashed line245/75R17Width 9.6 in (245 mm)Sidewall 7.2 in (184 mm)265/55R20Width 10.4 in (265 mm)Sidewall 5.7 in (146 mm)
245/75R17 is drawn with a solid line and 265/55R20 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 245/75R17 and 265/55R20, with the difference (265/55R20 minus 245/75R17)
Measurement245/75R17265/55R20DifferenceDifference %
Section width9.6 in (245 mm)10.4 in (265 mm)+0.8 in (+20 mm)+8.16%
Sidewall height7.2 in (184 mm)5.7 in (146 mm)-1.5 in (-38 mm)-20.68%
Wheel (rim) diameter17.0 in (432 mm)20.0 in (508 mm)+3.0 in (+76 mm)+17.65%
Overall diameter31.5 in (799 mm)31.5 in (800 mm)0.0 in (+1 mm)+0.03%
Circumference98.9 in (2511 mm)98.9 in (2512 mm)0.0 in (+1 mm)+0.03%
Revolutions per mile6416410-0.03%

Differences are 265/55R20 minus 245/75R17; percentages are relative to 245/75R17. These are nominal design dimensions. Real tires vary by brand, tread depth, wheel width, load and pressure.

The overall diameter differs by 0.03%, 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 245/75R17, the actual speed on 265/55R20 is about 60.0 mph. When it reads 60 mph on a vehicle built for 265/55R20, the actual speed on 245/75R17 is about 60.0 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, 245/75R17 against 265/55R20
Speedometer readsActual on 265/55R20 (built for 245/75R17)Actual on 245/75R17 (built for 265/55R20)
20 mph20.0 mph20.0 mph
30 mph30.0 mph30.0 mph
40 mph40.0 mph40.0 mph
50 mph50.0 mph50.0 mph
60 mph60.0 mph60.0 mph
70 mph70.0 mph70.0 mph
80 mph80.0 mph80.0 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 245/75R17 or 265/55R20 tires

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Other comparisons with 245/75R17

Side-by-side dimensions and speedometer difference for sizes close to 245/75R17 in overall diameter.

Other comparisons with 265/55R20

Side-by-side dimensions and speedometer difference for sizes close to 265/55R20 in overall diameter.

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