Tire Size Box

205/45R16 vs 205/55R16

205/55R16 compared with 205/45R16

+6.9% diameter, 0.0" width

205/55R16 is 24.88" tall vs 23.26". More than the 3% rule of thumb, so check carefully before switching.

23.3"16" rim3.6"8.1" wide
205/45R16 (solid) compared with 205/55R16 (dashed outline), drawn to scale

With 205/55R16 tires, when your speedometer says 60 mph you are really going

64.2 mph

205/55R16 is +1.61 inches (+6.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

205/45R16205/55R16Difference%
Overall diameter23.26"24.88"+1.61"+6.9%
Section width8.07"8.07"0.00"0.0%
Sidewall height3.63"4.44"+0.81"+22.2%
Circumference73.09"78.16"+5.07"+6.9%
Revolutions per mile866.9810.7−56.2−6.5%

Speedometer difference

If your vehicle came with 205/45R16 and you fit 205/55R16, 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 mph53.5 mph+3.5 mph
60 mph64.2 mph+4.2 mph
65 mph69.5 mph+4.5 mph
70 mph74.9 mph+4.9 mph
75 mph80.2 mph+5.2 mph
80 mph85.6 mph+5.6 mph

Each size on its own

Questions

Which is bigger, 205/45R16 or 205/55R16?
205/55R16 is taller by 1.61 inches (24.88" vs 23.26"). 205/45R16 is the same width.
Can I replace 205/45R16 with 205/55R16?
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 205/55R16 change my speedometer?
When your speedometer reads 60 mph with 205/55R16 fitted (calibrated for 205/45R16), your real speed is 64.2 mph. Your odometer will under-count miles by about 6.9%.
Will 205/55R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.81 inches of ground clearance at the axle.

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