Tire Size Box

185/65R17 vs 205/65R17

205/65R17 compared with 185/65R17

+3.9% diameter, +0.8" width

205/65R17 is 27.49" tall vs 26.47". More than the 3% rule of thumb, so check carefully before switching.

26.5"17" rim4.7"7.3" wide
185/65R17 (solid) compared with 205/65R17 (dashed outline), drawn to scale

With 205/65R17 tires, when your speedometer says 60 mph you are really going

62.3 mph

205/65R17 is +1.02 inches (+3.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/65R17205/65R17Difference%
Overall diameter26.47"27.49"+1.02"+3.9%
Section width7.28"8.07"+0.79"+10.8%
Sidewall height4.73"5.25"+0.51"+10.8%
Circumference83.15"86.37"+3.22"+3.9%
Revolutions per mile762.0733.6−28.4−3.7%

Speedometer difference

If your vehicle came with 185/65R17 and you fit 205/65R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.2 mph+1.2 mph
40 mph41.5 mph+1.5 mph
50 mph51.9 mph+1.9 mph
60 mph62.3 mph+2.3 mph
65 mph67.5 mph+2.5 mph
70 mph72.7 mph+2.7 mph
75 mph77.9 mph+2.9 mph
80 mph83.1 mph+3.1 mph

Each size on its own

Questions

Which is bigger, 185/65R17 or 205/65R17?
205/65R17 is taller by 1.02 inches (27.49" vs 26.47"). 205/65R17 is wider by 0.79 inches.
Can I replace 185/65R17 with 205/65R17?
It is not recommended without checking carefully. The diameter difference is +3.9%, 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 205/65R17 change my speedometer?
When your speedometer reads 60 mph with 205/65R17 fitted (calibrated for 185/65R17), your real speed is 62.3 mph. Your odometer will under-count miles by about 3.9%.
Will 205/65R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.51 inches of ground clearance at the axle.

Other comparisons