TireSizesFinder

205/55R15 vs 175/65R15

175/65R15 is 0.08 in (2.0 mm) taller than 205/55R15, a +0.33% diameter difference. With the speedometer set for 205/55R15, an indicated 60 mph is 60.2 mph on 175/65R15.

Is this a safe swap?

Diameter difference +0.33%: under 1%

By overall diameter alone, 175/65R15 is a near match for 205/55R15; 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: 205/55R15 (23.88 in) vs 175/65R15 (23.96 in)205/55R1523.88 in × 8.07 in175/65R1523.96 in × 6.89 in
Side profile and tread width, drawn to the same scale.
205/55R15 vs 175/65R15 differences
Measurement205/55R15175/65R15Difference% diff
Overall diameter23.88 in (606.5 mm)23.96 in (608.5 mm)+0.08 in (+2.0 mm)+0.33%
Sidewall height4.44 in (112.8 mm)4.48 in (113.8 mm)+0.04 in (+1.0 mm)+0.89%
Section width8.07 in (205.0 mm)6.89 in (175.0 mm)−1.18 in (−30.0 mm)−14.63%
Circumference75.01 in (1,905.4 mm)75.26 in (1,911.7 mm)+0.25 in (+6.3 mm)+0.33%
Revolutions per mile845842−3−0.33%
True speed with the speedometer calibrated for 205/55R15
IndicatedActual on 205/55R15Actual on 175/65R15Difference
30 mph30.0 mph30.1 mph+0.1 mph
60 mph60.0 mph60.2 mph+0.2 mph
75 mph75.0 mph75.2 mph+0.2 mph

Ride-height change: 175/65R15 raises the vehicle by 0.04 in (1.0 mm) at the axle (half the +2.0 mm diameter difference).

175/65R15 is 0.08 in taller than 205/55R15 and 30 mm narrower, a 0.33% difference in overall diameter.

With the speedometer calibrated for 205/55R15, an indicated 60 mph is actually 60.2 mph on 175/65R15, and revolutions per mile change from 845 to 842.

Both sizes mount on 15-inch wheels.

Size pages

Other comparisons with 205/55R15

Other comparisons with 175/65R15

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