Tire Size Box

185/70R13 vs 205/70R13

205/70R13 compared with 185/70R13

+4.8% diameter, +0.8" width

205/70R13 is 24.30" tall vs 23.20". More than the 3% rule of thumb, so check carefully before switching.

23.2"13" rim5.1"7.3" wide
185/70R13 (solid) compared with 205/70R13 (dashed outline), drawn to scale

With 205/70R13 tires, when your speedometer says 60 mph you are really going

62.9 mph

205/70R13 is +1.10 inches (+4.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/70R13205/70R13Difference%
Overall diameter23.20"24.30"+1.10"+4.8%
Section width7.28"8.07"+0.79"+10.8%
Sidewall height5.10"5.65"+0.55"+10.8%
Circumference72.88"76.34"+3.46"+4.8%
Revolutions per mile869.4830.0−39.4−4.5%

Speedometer difference

If your vehicle came with 185/70R13 and you fit 205/70R13, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.0 mph+1.0 mph
30 mph31.4 mph+1.4 mph
40 mph41.9 mph+1.9 mph
50 mph52.4 mph+2.4 mph
60 mph62.9 mph+2.9 mph
65 mph68.1 mph+3.1 mph
70 mph73.3 mph+3.3 mph
75 mph78.6 mph+3.6 mph
80 mph83.8 mph+3.8 mph

Each size on its own

Questions

Which is bigger, 185/70R13 or 205/70R13?
205/70R13 is taller by 1.10 inches (24.30" vs 23.20"). 205/70R13 is wider by 0.79 inches.
Can I replace 185/70R13 with 205/70R13?
It is not recommended without checking carefully. The diameter difference is +4.8%, 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 205/70R13 change my speedometer?
When your speedometer reads 60 mph with 205/70R13 fitted (calibrated for 185/70R13), your real speed is 62.9 mph. Your odometer will under-count miles by about 4.8%.
Will 205/70R13 lift my vehicle?
Ride height changes by half the diameter difference: +0.55 inches of ground clearance at the axle.

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