Tire Size Box

205/50R17 vs 205/55R17

205/55R17 compared with 205/50R17

+3.2% diameter, 0.0" width

205/55R17 is 25.88" tall vs 25.07". More than the 3% rule of thumb, so check carefully before switching.

25.1"17" rim4.0"8.1" wide
205/50R17 (solid) compared with 205/55R17 (dashed outline), drawn to scale

With 205/55R17 tires, when your speedometer says 60 mph you are really going

61.9 mph

205/55R17 is +0.81 inches (+3.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

205/50R17205/55R17Difference%
Overall diameter25.07"25.88"+0.81"+3.2%
Section width8.07"8.07"0.00"0.0%
Sidewall height4.04"4.44"+0.40"+10.0%
Circumference78.76"81.30"+2.54"+3.2%
Revolutions per mile804.4779.4−25.1−3.1%

Speedometer difference

If your vehicle came with 205/50R17 and you fit 205/55R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph61.9 mph+1.9 mph
65 mph67.1 mph+2.1 mph
70 mph72.3 mph+2.3 mph
75 mph77.4 mph+2.4 mph
80 mph82.6 mph+2.6 mph

Each size on its own

Questions

Which is bigger, 205/50R17 or 205/55R17?
205/55R17 is taller by 0.81 inches (25.88" vs 25.07"). 205/50R17 is the same width.
Can I replace 205/50R17 with 205/55R17?
It is not recommended without checking carefully. The diameter difference is +3.2%, 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 205/55R17 change my speedometer?
When your speedometer reads 60 mph with 205/55R17 fitted (calibrated for 205/50R17), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.2%.
Will 205/55R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.40 inches of ground clearance at the axle.

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