TireSizesFinder

185/70R13 vs 165/65R15

165/65R15 is 0.25 in (6.3 mm) taller than 185/70R13, a +1.07% diameter difference. With the speedometer set for 185/70R13, an indicated 60 mph is 60.6 mph on 165/65R15.

Is this a safe swap?

Diameter difference +1.07%: within the ±3% guideline

By overall diameter alone, 165/65R15 falls inside the ±3% range commonly used as a guideline when replacing 185/70R13. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 185/70R13 (23.20 in) vs 165/65R15 (23.44 in)185/70R1323.20 in × 7.28 in165/65R1523.44 in × 6.50 in
Side profile and tread width, drawn to the same scale.
185/70R13 vs 165/65R15 differences
Measurement185/70R13165/65R15Difference% diff
Overall diameter23.20 in (589.2 mm)23.44 in (595.5 mm)+0.25 in (+6.3 mm)+1.07%
Sidewall height5.10 in (129.5 mm)4.22 in (107.3 mm)−0.88 in (−22.2 mm)−17.18%
Section width7.28 in (185.0 mm)6.50 in (165.0 mm)−0.79 in (−20.0 mm)−10.81%
Circumference72.88 in (1,851.0 mm)73.65 in (1,870.8 mm)+0.78 in (+19.8 mm)+1.07%
Revolutions per mile869860−9−1.06%
True speed with the speedometer calibrated for 185/70R13
IndicatedActual on 185/70R13Actual on 165/65R15Difference
30 mph30.0 mph30.3 mph+0.3 mph
60 mph60.0 mph60.6 mph+0.6 mph
75 mph75.0 mph75.8 mph+0.8 mph

Ride-height change: 165/65R15 raises the vehicle by 0.12 in (3.1 mm) at the axle (half the +6.3 mm diameter difference).

165/65R15 is 0.25 in taller than 185/70R13 and 20 mm narrower, a 1.07% difference in overall diameter.

With the speedometer calibrated for 185/70R13, an indicated 60 mph is actually 60.6 mph on 165/65R15, and revolutions per mile change from 869 to 860.

165/65R15 mounts on a 15-inch wheel, a plus-2 fitment from the 13-inch wheel of 185/70R13.

Size pages

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Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.