Tire Size Box

215/45R15 vs 215/55R15

215/55R15 compared with 215/45R15

+7.5% diameter, 0.0" width

215/55R15 is 24.31" 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 215/55R15 (dashed outline), drawn to scale

With 215/55R15 tires, when your speedometer says 60 mph you are really going

64.5 mph

215/55R15 is +1.69 inches (+7.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/45R15215/55R15Difference%
Overall diameter22.62"24.31"+1.69"+7.5%
Section width8.46"8.46"0.00"0.0%
Sidewall height3.81"4.66"+0.85"+22.2%
Circumference71.06"76.38"+5.32"+7.5%
Revolutions per mile891.7829.6−62.1−7.0%

Speedometer difference

If your vehicle came with 215/45R15 and you fit 215/55R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.2 mph+2.2 mph
40 mph43.0 mph+3.0 mph
50 mph53.7 mph+3.7 mph
60 mph64.5 mph+4.5 mph
65 mph69.9 mph+4.9 mph
70 mph75.2 mph+5.2 mph
75 mph80.6 mph+5.6 mph
80 mph86.0 mph+6.0 mph

Each size on its own

Questions

Which is bigger, 215/45R15 or 215/55R15?
215/55R15 is taller by 1.69 inches (24.31" vs 22.62"). 215/45R15 is the same width.
Can I replace 215/45R15 with 215/55R15?
It is not recommended without checking carefully. The diameter difference is +7.5%, 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 215/55R15 change my speedometer?
When your speedometer reads 60 mph with 215/55R15 fitted (calibrated for 215/45R15), your real speed is 64.5 mph. Your odometer will under-count miles by about 7.5%.
Will 215/55R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.85 inches of ground clearance at the axle.

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