Tire Size Box

215/45R15 vs 235/45R15

235/45R15 compared with 215/45R15

+3.1% diameter, +0.8" width

235/45R15 is 23.33" tall vs 22.62". More than the 3% rule of thumb, so check carefully before switching.

22.6"15" rim3.8"8.5" wide
215/45R15 (solid) compared with 235/45R15 (dashed outline), drawn to scale

With 235/45R15 tires, when your speedometer says 60 mph you are really going

61.9 mph

235/45R15 is +0.71 inches (+3.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/45R15235/45R15Difference%
Overall diameter22.62"23.33"+0.71"+3.1%
Section width8.46"9.25"+0.79"+9.3%
Sidewall height3.81"4.16"+0.35"+9.3%
Circumference71.06"73.28"+2.23"+3.1%
Revolutions per mile891.7864.6−27.1−3.0%

Speedometer difference

If your vehicle came with 215/45R15 and you fit 235/45R15, 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 mph41.3 mph+1.3 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, 215/45R15 or 235/45R15?
235/45R15 is taller by 0.71 inches (23.33" vs 22.62"). 235/45R15 is wider by 0.79 inches.
Can I replace 215/45R15 with 235/45R15?
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 235/45R15 change my speedometer?
When your speedometer reads 60 mph with 235/45R15 fitted (calibrated for 215/45R15), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.1%.
Will 235/45R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.35 inches of ground clearance at the axle.

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