TireSizesFinder

205/50R15 vs 165/65R15

165/65R15 is 0.37 in (9.5 mm) taller than 205/50R15, a +1.62% diameter difference. With the speedometer set for 205/50R15, an indicated 60 mph is 61.0 mph on 165/65R15.

Is this a safe swap?

Diameter difference +1.62%: within the ±3% guideline

By overall diameter alone, 165/65R15 falls inside the ±3% range commonly used as a guideline when replacing 205/50R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 205/50R15 (23.07 in) vs 165/65R15 (23.44 in)205/50R1523.07 in × 8.07 in165/65R1523.44 in × 6.50 in
Side profile and tread width, drawn to the same scale.
205/50R15 vs 165/65R15 differences
Measurement205/50R15165/65R15Difference% diff
Overall diameter23.07 in (586.0 mm)23.44 in (595.5 mm)+0.37 in (+9.5 mm)+1.62%
Sidewall height4.04 in (102.5 mm)4.22 in (107.3 mm)+0.19 in (+4.8 mm)+4.63%
Section width8.07 in (205.0 mm)6.50 in (165.0 mm)−1.57 in (−40.0 mm)−19.51%
Circumference72.48 in (1,841.0 mm)73.65 in (1,870.8 mm)+1.18 in (+29.8 mm)+1.62%
Revolutions per mile874860−14−1.60%
True speed with the speedometer calibrated for 205/50R15
IndicatedActual on 205/50R15Actual on 165/65R15Difference
30 mph30.0 mph30.5 mph+0.5 mph
60 mph60.0 mph61.0 mph+1.0 mph
75 mph75.0 mph76.2 mph+1.2 mph

Ride-height change: 165/65R15 raises the vehicle by 0.19 in (4.8 mm) at the axle (half the +9.5 mm diameter difference).

165/65R15 is 0.37 in taller than 205/50R15 and 40 mm narrower, a 1.62% difference in overall diameter.

With the speedometer calibrated for 205/50R15, an indicated 60 mph is actually 61.0 mph on 165/65R15, and revolutions per mile change from 874 to 860.

Both sizes mount on 15-inch wheels.

Size pages

Other comparisons with 205/50R15

Other comparisons with 165/65R15

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