Tire Size Box

215/55R15 vs 235/55R15

235/55R15 compared with 215/55R15

+3.6% diameter, +0.8" width

235/55R15 is 25.18" tall vs 24.31". More than the 3% rule of thumb, so check carefully before switching.

24.3"15" rim4.7"8.5" wide
215/55R15 (solid) compared with 235/55R15 (dashed outline), drawn to scale

With 235/55R15 tires, when your speedometer says 60 mph you are really going

62.1 mph

235/55R15 is +0.87 inches (+3.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/55R15235/55R15Difference%
Overall diameter24.31"25.18"+0.87"+3.6%
Section width8.46"9.25"+0.79"+9.3%
Sidewall height4.66"5.09"+0.43"+9.3%
Circumference76.38"79.10"+2.72"+3.6%
Revolutions per mile829.6801.0−28.5−3.4%

Speedometer difference

If your vehicle came with 215/55R15 and you fit 235/55R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.4 mph+1.4 mph
50 mph51.8 mph+1.8 mph
60 mph62.1 mph+2.1 mph
65 mph67.3 mph+2.3 mph
70 mph72.5 mph+2.5 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 215/55R15 or 235/55R15?
235/55R15 is taller by 0.87 inches (25.18" vs 24.31"). 235/55R15 is wider by 0.79 inches.
Can I replace 215/55R15 with 235/55R15?
It is not recommended without checking carefully. The diameter difference is +3.6%, 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 235/55R15 change my speedometer?
When your speedometer reads 60 mph with 235/55R15 fitted (calibrated for 215/55R15), your real speed is 62.1 mph. Your odometer will under-count miles by about 3.6%.
Will 235/55R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.43 inches of ground clearance at the axle.

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