255/40R16 tire size in inches

A 255/40R16 tire measures

24.0" tall × 10.0" wide

4.02" sidewall on a 16" wheel. 839 revolutions per mile.

255/40R16 means a tire 255 mm wide, with sidewalls 40% as tall as the tire is wide (102 mm), radial construction (R), for a 16 inch wheel.

24.0"16" rim4.0"10.0" wide
255/40R16: 24.0 inches tall, 10.0 inches wide, on a 16 inch rim, drawn to scale

255/40R16 specs

Overall diameter (height)24.03 inches (610 mm)
Section width10.04 inches (255 mm)
Sidewall height4.02 inches (102 mm)
Wheel (rim) diameter16 inches
Circumference75.5 inches (1,918 mm)
Revolutions per mile839
Revolutions per kilometer521
Approximate rim width8.5" to 10.0"
In inches (flotation style)24.0x10.0R16
Aspect ratio40%

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 255/40R16 on a 16" wheel

These 16" sizes are within 3% of 255/40R16's overall diameter, the range most tire shops treat as interchangeable.

SizeDiameterWidthDifferenceReal speed at 60
185/55R1624.01"7.28"−0.1%60.0 mphCompare
205/50R1624.07"8.07"+0.2%60.1 mphCompare
225/45R1623.97"8.86"−0.2%59.9 mphCompare
175/60R1624.27"6.89"+1.0%60.6 mphCompare
235/45R1624.33"9.25"+1.2%60.7 mphCompare
245/40R1623.72"9.65"−1.3%59.2 mphCompare
265/40R1624.35"10.43"+1.3%60.8 mphCompare
195/50R1623.68"7.68"−1.5%59.1 mphCompare
195/55R1624.44"7.68"+1.7%61.0 mphCompare
215/45R1623.62"8.46"−1.7%59.0 mphCompare
215/50R1624.46"8.46"+1.8%61.1 mphCompare
175/55R1623.58"6.89"−1.9%58.9 mphCompare

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

SizeWheelDiameterDifference
255/45R1515"24.04"0.0%Compare
255/35R1717"24.03"0.0%Compare
175/80R1313"24.02"0.0%Compare
165/85R1313"24.04"0.0%Compare
255/25R1919"24.02"0.0%Compare
215/65R1313"24.00"−0.1%Compare
215/30R1919"24.08"+0.2%Compare
195/65R1414"23.98"−0.2%Compare
225/40R1717"24.09"+0.2%Compare
165/70R1515"24.09"+0.3%Compare
235/60R1313"24.10"+0.3%Compare
175/65R1515"23.96"−0.3%Compare

One size up or down

Compare 255/40R16 with another size

With 265/40R16 tires, when your speedometer says 60 mph you are really going

60.8 mph

265/40R16 is +0.31 inches (+1.3%) in overall diameter. That is within the 3% most shops and makers allow.

255/40R16265/40R16Difference%
Overall diameter24.03"24.35"+0.31"+1.3%
Section width10.04"10.43"+0.39"+3.9%
Sidewall height4.02"4.17"+0.16"+3.9%
Circumference75.50"76.49"+0.99"+1.3%
Revolutions per mile839.2828.4−10.9−1.3%

Questions

How tall is a 255/40R16 tire?
A 255/40R16 tire is 24.0 inches tall (610 mm), calculated from the size. It is 10.0 inches wide with 4.0 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
What does 255/40R16 mean?
255/40R16 means a tire 255 mm wide, with sidewalls 40% as tall as the tire is wide (102 mm), radial construction (R), for a 16 inch wheel.
How many revolutions per mile does a 255/40R16 tire make?
About 839 revolutions per mile, based on a circumference of 75.5 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
What rim width fits a 255/40R16 tire?
Roughly 8.5" to 10.0". Check the tire maker's approved rim range for the exact model before buying wheels.
Can I use 185/55R16 instead of 255/40R16?
185/55R16 is −0.02 inches (−0.1%) in overall diameter, so at an indicated 60 mph you would be doing 60.0 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.

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