Tire Size Box

215/45R17 vs 215/55R17

215/55R17 compared with 215/45R17

+6.9% diameter, 0.0" width

215/55R17 is 26.31" tall vs 24.62". More than the 3% rule of thumb, so check carefully before switching.

24.6"17" rim3.8"8.5" wide
215/45R17 (solid) compared with 215/55R17 (dashed outline), drawn to scale

With 215/55R17 tires, when your speedometer says 60 mph you are really going

64.1 mph

215/55R17 is +1.69 inches (+6.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/45R17215/55R17Difference%
Overall diameter24.62"26.31"+1.69"+6.9%
Section width8.46"8.46"0.00"0.0%
Sidewall height3.81"4.66"+0.85"+22.2%
Circumference77.34"82.66"+5.32"+6.9%
Revolutions per mile819.2766.5−52.7−6.4%

Speedometer difference

If your vehicle came with 215/45R17 and you fit 215/55R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.1 mph+2.1 mph
40 mph42.8 mph+2.8 mph
50 mph53.4 mph+3.4 mph
60 mph64.1 mph+4.1 mph
65 mph69.5 mph+4.5 mph
70 mph74.8 mph+4.8 mph
75 mph80.2 mph+5.2 mph
80 mph85.5 mph+5.5 mph

Each size on its own

Questions

Which is bigger, 215/45R17 or 215/55R17?
215/55R17 is taller by 1.69 inches (26.31" vs 24.62"). 215/45R17 is the same width.
Can I replace 215/45R17 with 215/55R17?
It is not recommended without checking carefully. The diameter difference is +6.9%, 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 215/55R17 change my speedometer?
When your speedometer reads 60 mph with 215/55R17 fitted (calibrated for 215/45R17), your real speed is 64.1 mph. Your odometer will under-count miles by about 6.9%.
Will 215/55R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.85 inches of ground clearance at the axle.

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