Tire Size Box

185/85R13 vs 205/70R14

205/70R14 compared with 185/85R13

−0.3% diameter, +0.8" width

205/70R14 is 25.30" tall vs 25.38". Within the 3% rule, so usually interchangeable.

25.4"13" rim6.2"7.3" wide
185/85R13 (solid) compared with 205/70R14 (dashed outline), drawn to scale

With 205/70R14 tires, when your speedometer says 60 mph you are really going

59.8 mph

205/70R14 is −0.08 inches (−0.3%) in overall diameter. That is within the 3% most shops and makers allow.

185/85R13205/70R14Difference%
Overall diameter25.38"25.30"−0.08"−0.3%
Section width7.28"8.07"+0.79"+10.8%
Sidewall height6.19"5.65"−0.54"−8.7%
Circumference79.74"79.48"−0.26"−0.3%
Revolutions per mile794.6797.2+2.6+0.3%

Speedometer difference

If your vehicle came with 185/85R13 and you fit 205/70R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph19.9 mph−0.1 mph
30 mph29.9 mph−0.1 mph
40 mph39.9 mph−0.1 mph
50 mph49.8 mph−0.2 mph
60 mph59.8 mph−0.2 mph
65 mph64.8 mph−0.2 mph
70 mph69.8 mph−0.2 mph
75 mph74.8 mph−0.2 mph
80 mph79.7 mph−0.3 mph

Each size on its own

Questions

Which is bigger, 185/85R13 or 205/70R14?
185/85R13 is taller by 0.08 inches (25.38" vs 25.30"). 205/70R14 is wider by 0.79 inches.
Can I replace 185/85R13 with 205/70R14?
Usually, yes. The diameter difference is −0.3%, inside the 3% rule of thumb most tire shops use. Check that the wider or taller tire clears your suspension and fenders, and that its load index meets your placard.
How much will 205/70R14 change my speedometer?
When your speedometer reads 60 mph with 205/70R14 fitted (calibrated for 185/85R13), your real speed is 59.8 mph. Your odometer will over-count miles by about 0.3%.
Will 205/70R14 lift my vehicle?
Ride height changes by half the diameter difference: −0.04 inches of ground clearance at the axle.

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