TireSizesFinder

185/70R14 vs 175/65R15

175/65R15 is 0.24 in (6.1 mm) shorter than 185/70R14, a −0.99% diameter difference. With the speedometer set for 185/70R14, an indicated 60 mph is 59.4 mph on 175/65R15.

Is this a safe swap?

Diameter difference −0.99%: under 1%

By overall diameter alone, 175/65R15 is a near match for 185/70R14; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 185/70R14 (24.20 in) vs 175/65R15 (23.96 in)185/70R1424.20 in × 7.28 in175/65R1523.96 in × 6.89 in
Side profile and tread width, drawn to the same scale.
185/70R14 vs 175/65R15 differences
Measurement185/70R14175/65R15Difference% diff
Overall diameter24.20 in (614.6 mm)23.96 in (608.5 mm)−0.24 in (−6.1 mm)−0.99%
Sidewall height5.10 in (129.5 mm)4.48 in (113.8 mm)−0.62 in (−15.7 mm)−12.16%
Section width7.28 in (185.0 mm)6.89 in (175.0 mm)−0.39 in (−10.0 mm)−5.41%
Circumference76.02 in (1,930.8 mm)75.26 in (1,911.7 mm)−0.75 in (−19.2 mm)−0.99%
Revolutions per mile834842+8+1.00%
True speed with the speedometer calibrated for 185/70R14
IndicatedActual on 185/70R14Actual on 175/65R15Difference
30 mph30.0 mph29.7 mph−0.3 mph
60 mph60.0 mph59.4 mph−0.6 mph
75 mph75.0 mph74.3 mph−0.7 mph

Ride-height change: 175/65R15 lowers the vehicle by 0.12 in (3.0 mm) at the axle (half the −6.1 mm diameter difference).

175/65R15 is 0.24 in shorter than 185/70R14 and 10 mm narrower, a 0.99% difference in overall diameter.

With the speedometer calibrated for 185/70R14, an indicated 60 mph is actually 59.4 mph on 175/65R15, and revolutions per mile change from 834 to 842.

175/65R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 185/70R14.

Size pages

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