175/70R14 vs 175/65R15

175/65R15 is 0.31 in (7.9 mm) taller than 175/70R14, a +1.32% diameter difference. With the speedometer set for 175/70R14, an indicated 60 mph is 60.8 mph on 175/65R15.

Is this a safe swap?

Diameter difference +1.32%: within the ±3% guideline

By overall diameter alone, 175/65R15 falls inside the ±3% range commonly used as a guideline when replacing 175/70R14. 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.

175/70R14 vs 175/65R15 differences
Measurement	175/70R14	175/65R15	Difference	% diff
Overall diameter	23.65 in (600.6 mm)	23.96 in (608.5 mm)	+0.31 in (+7.9 mm)	+1.32%
Sidewall height	4.82 in (122.5 mm)	4.48 in (113.8 mm)	−0.34 in (−8.7 mm)	−7.14%
Section width	6.89 in (175.0 mm)	6.89 in (175.0 mm)	0.00 in (0.0 mm)	0.00%
Circumference	74.29 in (1,886.8 mm)	75.26 in (1,911.7 mm)	+0.98 in (+24.8 mm)	+1.32%
Revolutions per mile	853	842	−11	−1.30%

True speed with the speedometer calibrated for 175/70R14
Indicated	Actual on 175/70R14	Actual on 175/65R15	Difference
30 mph	30.0 mph	30.4 mph	+0.4 mph
60 mph	60.0 mph	60.8 mph	+0.8 mph
75 mph	75.0 mph	76.0 mph	+1.0 mph

Ride-height change: 175/65R15 raises the vehicle by 0.16 in (4.0 mm) at the axle (half the +7.9 mm diameter difference).

175/65R15 is 0.31 in taller than 175/70R14 and the same width, a 1.32% difference in overall diameter.

With the speedometer calibrated for 175/70R14, an indicated 60 mph is actually 60.8 mph on 175/65R15, and revolutions per mile change from 853 to 842.

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

Size pages

Other comparisons with 175/70R14

Other comparisons with 175/65R15

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