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255/50R20 vs 255/55R19 tire size comparison

255/50R20255/55R19

255/55R19 is 0.00 in (0.01%) taller than 255/50R20, with the same section width. They fit different wheels: 255/50R20 a 20-inch wheel and 255/55R19 a 19-inch wheel.

255/50R20 and 255/55R19 side by side

0.0 in / +0.01%255/50R20: 30.0 in tall, solid line255/55R19: 30.0 in tall, dashed line255/50R20Width 10.0 in (255 mm)Sidewall 5.0 in (128 mm)255/55R19Width 10.0 in (255 mm)Sidewall 5.5 in (140 mm)
255/50R20 is drawn with a solid line and 255/55R19 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 255/50R20 and 255/55R19, with the difference (255/55R19 minus 255/50R20)
Measurement255/50R20255/55R19DifferenceDifference %
Section width10.0 in (255 mm)10.0 in (255 mm)0.0 in (0 mm)0.00%
Sidewall height5.0 in (128 mm)5.5 in (140 mm)+0.5 in (+12 mm)+10.00%
Wheel (rim) diameter20.0 in (508 mm)19.0 in (483 mm)-1.0 in (-25 mm)-5.00%
Overall diameter30.0 in (763 mm)30.0 in (763 mm)0.0 in (0 mm)+0.01%
Circumference94.4 in (2397 mm)94.4 in (2397 mm)0.0 in (0 mm)+0.01%
Revolutions per mile6716710-0.01%

Differences are 255/55R19 minus 255/50R20; percentages are relative to 255/50R20. These are nominal design dimensions. Real tires vary by brand, tread depth, wheel width, load and pressure.

The overall diameter differs by 0.01%, 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 255/50R20, the actual speed on 255/55R19 is about 60.0 mph. When it reads 60 mph on a vehicle built for 255/55R19, the actual speed on 255/50R20 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, 255/50R20 against 255/55R19
Speedometer readsActual on 255/55R19 (built for 255/50R20)Actual on 255/50R20 (built for 255/55R19)
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.

Open this comparison in the calculator

Shop for 255/50R20 or 255/55R19 tires

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Other comparisons with 255/50R20

Side-by-side dimensions and speedometer difference for sizes close to 255/50R20 in overall diameter.

Other comparisons with 255/55R19

Side-by-side dimensions and speedometer difference for sizes close to 255/55R19 in overall diameter.

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