TireSizesFinder

225/50R15 vs 175/65R15

175/65R15 is 0.10 in (2.5 mm) taller than 225/50R15, a +0.41% diameter difference. With the speedometer set for 225/50R15, an indicated 60 mph is 60.2 mph on 175/65R15.

Is this a safe swap?

Diameter difference +0.41%: under 1%

By overall diameter alone, 175/65R15 is a near match for 225/50R15; 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: 225/50R15 (23.86 in) vs 175/65R15 (23.96 in)225/50R1523.86 in × 8.86 in175/65R1523.96 in × 6.89 in
Side profile and tread width, drawn to the same scale.
225/50R15 vs 175/65R15 differences
Measurement225/50R15175/65R15Difference% diff
Overall diameter23.86 in (606.0 mm)23.96 in (608.5 mm)+0.10 in (+2.5 mm)+0.41%
Sidewall height4.43 in (112.5 mm)4.48 in (113.8 mm)+0.05 in (+1.3 mm)+1.11%
Section width8.86 in (225.0 mm)6.89 in (175.0 mm)−1.97 in (−50.0 mm)−22.22%
Circumference74.95 in (1,903.8 mm)75.26 in (1,911.7 mm)+0.31 in (+7.9 mm)+0.41%
Revolutions per mile845842−3−0.41%
True speed with the speedometer calibrated for 225/50R15
IndicatedActual on 225/50R15Actual on 175/65R15Difference
30 mph30.0 mph30.1 mph+0.1 mph
60 mph60.0 mph60.2 mph+0.2 mph
75 mph75.0 mph75.3 mph+0.3 mph

Ride-height change: 175/65R15 raises the vehicle by 0.05 in (1.3 mm) at the axle (half the +2.5 mm diameter difference).

175/65R15 is 0.10 in taller than 225/50R15 and 50 mm narrower, a 0.41% difference in overall diameter.

With the speedometer calibrated for 225/50R15, 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 225/50R15

Other comparisons with 175/65R15

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