185/65R14 vs 175/70R14

175/70R14 is 0.18 in (4.5 mm) taller than 185/65R14, a +0.75% diameter difference. With the speedometer set for 185/65R14, an indicated 60 mph is 60.5 mph on 175/70R14.

Is this a safe swap?

Diameter difference +0.75%: under 1%

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

Side profile and tread width, drawn to the same scale.

185/65R14 vs 175/70R14 differences
Measurement	185/65R14	175/70R14	Difference	% diff
Overall diameter	23.47 in (596.1 mm)	23.65 in (600.6 mm)	+0.18 in (+4.5 mm)	+0.75%
Sidewall height	4.73 in (120.3 mm)	4.82 in (122.5 mm)	+0.09 in (+2.3 mm)	+1.87%
Section width	7.28 in (185.0 mm)	6.89 in (175.0 mm)	−0.39 in (−10.0 mm)	−5.41%
Circumference	73.73 in (1,872.7 mm)	74.29 in (1,886.8 mm)	+0.56 in (+14.1 mm)	+0.75%
Revolutions per mile	859	853	−6	−0.75%

True speed with the speedometer calibrated for 185/65R14
Indicated	Actual on 185/65R14	Actual on 175/70R14	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.5 mph	+0.5 mph
75 mph	75.0 mph	75.6 mph	+0.6 mph

Ride-height change: 175/70R14 raises the vehicle by 0.09 in (2.3 mm) at the axle (half the +4.5 mm diameter difference).

175/70R14 is 0.18 in taller than 185/65R14 and 10 mm narrower, a 0.75% difference in overall diameter.

With the speedometer calibrated for 185/65R14, an indicated 60 mph is actually 60.5 mph on 175/70R14, and revolutions per mile change from 859 to 853.

Both sizes mount on 14-inch wheels.

Size pages

Other comparisons with 185/65R14

Other comparisons with 175/70R14

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.