Tire Size Box

235/50R16 vs 255/50R16

255/50R16 compared with 235/50R16

+3.1% diameter, +0.8" width

255/50R16 is 26.04" tall vs 25.25". More than the 3% rule of thumb, so check carefully before switching.

25.3"16" rim4.6"9.3" wide
235/50R16 (solid) compared with 255/50R16 (dashed outline), drawn to scale

With 255/50R16 tires, when your speedometer says 60 mph you are really going

61.9 mph

255/50R16 is +0.79 inches (+3.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/50R16255/50R16Difference%
Overall diameter25.25"26.04"+0.79"+3.1%
Section width9.25"10.04"+0.79"+8.5%
Sidewall height4.63"5.02"+0.39"+8.5%
Circumference79.33"81.81"+2.47"+3.1%
Revolutions per mile798.7774.5−24.2−3.0%

Speedometer difference

If your vehicle came with 235/50R16 and you fit 255/50R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph30.9 mph+0.9 mph
40 mph41.2 mph+1.2 mph
50 mph51.6 mph+1.6 mph
60 mph61.9 mph+1.9 mph
65 mph67.0 mph+2.0 mph
70 mph72.2 mph+2.2 mph
75 mph77.3 mph+2.3 mph
80 mph82.5 mph+2.5 mph

Each size on its own

Questions

Which is bigger, 235/50R16 or 255/50R16?
255/50R16 is taller by 0.79 inches (26.04" vs 25.25"). 255/50R16 is wider by 0.79 inches.
Can I replace 235/50R16 with 255/50R16?
It is not recommended without checking carefully. The diameter difference is +3.1%, more than the 3% most shops and makers allow. It will throw off the speedometer and may affect ABS, stability control and clearance.
How much will 255/50R16 change my speedometer?
When your speedometer reads 60 mph with 255/50R16 fitted (calibrated for 235/50R16), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.1%.
Will 255/50R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.39 inches of ground clearance at the axle.

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