305/55R17 tire size in inches

A 305/55R17 tire measures

30.2" tall × 12.0" wide

6.60" sidewall on a 17" wheel. 668 revolutions per mile.

305/55R17 means a tire 305 mm wide, with sidewalls 55% as tall as the tire is wide (168 mm), radial construction (R), for a 17 inch wheel.

30.2"17" rim6.6"12.0" wide
305/55R17: 30.2 inches tall, 12.0 inches wide, on a 17 inch rim, drawn to scale

305/55R17 specs

Overall diameter (height)30.21 inches (767 mm)
Section width12.01 inches (305 mm)
Sidewall height6.60 inches (168 mm)
Wheel (rim) diameter17 inches
Circumference94.9 inches (2,411 mm)
Revolutions per mile668
Revolutions per kilometer415
Approximate rim width9.0" to 10.5"
In inches (flotation style)30.2x12.0R17
Aspect ratio55%

Calculated from the size. Real tires differ by brand, model and tread depth, typically by a few tenths of an inch.

Sizes that can replace 305/55R17 on a 17" wheel

These 17" sizes are within 3% of 305/55R17's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
225/75R1730.29"8.86"+0.3%60.2 mphCompare
255/65R1730.05"10.04"−0.5%59.7 mphCompare
275/60R1729.99"10.83"−0.7%59.6 mphCompare
285/60R1730.46"11.22"+0.8%60.5 mphCompare
235/70R1729.95"9.25"−0.8%59.5 mphCompare
245/70R1730.50"9.65"+1.0%60.6 mphCompare
265/65R1730.56"10.43"+1.2%60.7 mphCompare
295/55R1729.78"11.61"−1.4%59.1 mphCompare
315/55R1730.64"12.40"+1.4%60.9 mphCompare
215/75R1729.70"8.46"−1.7%59.0 mphCompare
235/75R1730.88"9.25"+2.2%61.3 mphCompare
245/65R1729.54"9.65"−2.2%58.7 mphCompare

Same height on other wheel sizes (plus and minus sizing)

SizeWheelDiameterDifference
315/25R2424"30.20"0.0%Compare
285/50R1919"30.22"0.0%Compare
335/35R2121"30.23"+0.1%Compare
325/40R2020"30.24"+0.1%Compare
355/40R1919"30.18"−0.1%Compare
235/55R2020"30.18"−0.1%Compare
225/80R1616"30.17"−0.1%Compare
235/50R2121"30.25"+0.1%Compare
315/45R1919"30.16"−0.2%Compare
265/30R2424"30.26"+0.2%Compare
215/60R2020"30.16"−0.2%Compare
275/70R1515"30.16"−0.2%Compare

One size up or down

Compare 305/55R17 with another size

With 315/55R17 tires, when your speedometer says 60 mph you are really going

60.9 mph

315/55R17 is +0.43 inches (+1.4%) in overall diameter. That is within the 3% most shops and makers allow.

305/55R17315/55R17Difference%
Overall diameter30.21"30.64"+0.43"+1.4%
Section width12.01"12.40"+0.39"+3.3%
Sidewall height6.60"6.82"+0.22"+3.3%
Circumference94.90"96.26"+1.36"+1.4%
Revolutions per mile667.6658.2−9.4−1.4%

Questions

How tall is a 305/55R17 tire?
A 305/55R17 tire is 30.2 inches tall (767 mm), calculated from the size. It is 12.0 inches wide with 6.6 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 305/55R17 mean?
305/55R17 means a tire 305 mm wide, with sidewalls 55% as tall as the tire is wide (168 mm), radial construction (R), for a 17 inch wheel.
How many revolutions per mile does a 305/55R17 tire make?
About 668 revolutions per mile, based on a circumference of 94.9 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 305/55R17 tire?
Roughly 9.0" to 10.5". Check the tire maker's approved rim range for the exact model before buying wheels.
Can I use 225/75R17 instead of 305/55R17?
225/75R17 is +0.08 inches (+0.3%) in overall diameter, so at an indicated 60 mph you would be doing 60.2 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.

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