Tire Size Box

185/70R16 vs 205/70R16

205/70R16 compared with 185/70R16

+4.2% diameter, +0.8" width

205/70R16 is 27.30" tall vs 26.20". More than the 3% rule of thumb, so check carefully before switching.

26.2"16" rim5.1"7.3" wide
185/70R16 (solid) compared with 205/70R16 (dashed outline), drawn to scale

With 205/70R16 tires, when your speedometer says 60 mph you are really going

62.5 mph

205/70R16 is +1.10 inches (+4.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/70R16205/70R16Difference%
Overall diameter26.20"27.30"+1.10"+4.2%
Section width7.28"8.07"+0.79"+10.8%
Sidewall height5.10"5.65"+0.55"+10.8%
Circumference82.30"85.76"+3.46"+4.2%
Revolutions per mile769.9738.8−31.1−4.0%

Speedometer difference

If your vehicle came with 185/70R16 and you fit 205/70R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.3 mph+1.3 mph
40 mph41.7 mph+1.7 mph
50 mph52.1 mph+2.1 mph
60 mph62.5 mph+2.5 mph
65 mph67.7 mph+2.7 mph
70 mph72.9 mph+2.9 mph
75 mph78.2 mph+3.2 mph
80 mph83.4 mph+3.4 mph

Each size on its own

Questions

Which is bigger, 185/70R16 or 205/70R16?
205/70R16 is taller by 1.10 inches (27.30" vs 26.20"). 205/70R16 is wider by 0.79 inches.
Can I replace 185/70R16 with 205/70R16?
It is not recommended without checking carefully. The diameter difference is +4.2%, 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 205/70R16 change my speedometer?
When your speedometer reads 60 mph with 205/70R16 fitted (calibrated for 185/70R16), your real speed is 62.5 mph. Your odometer will under-count miles by about 4.2%.
Will 205/70R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.55 inches of ground clearance at the axle.

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