TireSizesFinder

165/70R13 vs 185/70R13

185/70R13 is 1.10 in (28.0 mm) taller than 165/70R13, a +4.99% diameter difference. With the speedometer set for 165/70R13, an indicated 60 mph is 63.0 mph on 185/70R13.

Is this a safe swap?

Diameter difference +4.99%: outside the ±3% guideline

By overall diameter alone, 185/70R13 falls outside the ±3% range commonly used as a guideline when replacing 165/70R13; speedometer and ride-height changes are larger. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 165/70R13 (22.09 in) vs 185/70R13 (23.20 in)165/70R1322.09 in × 6.50 in185/70R1323.20 in × 7.28 in
Side profile and tread width, drawn to the same scale.
165/70R13 vs 185/70R13 differences
Measurement165/70R13185/70R13Difference% diff
Overall diameter22.09 in (561.2 mm)23.20 in (589.2 mm)+1.10 in (+28.0 mm)+4.99%
Sidewall height4.55 in (115.5 mm)5.10 in (129.5 mm)+0.55 in (+14.0 mm)+12.12%
Section width6.50 in (165.0 mm)7.28 in (185.0 mm)+0.79 in (+20.0 mm)+12.12%
Circumference69.41 in (1,763.1 mm)72.88 in (1,851.0 mm)+3.46 in (+88.0 mm)+4.99%
Revolutions per mile913869−43−4.75%
True speed with the speedometer calibrated for 165/70R13
IndicatedActual on 165/70R13Actual on 185/70R13Difference
30 mph30.0 mph31.5 mph+1.5 mph
60 mph60.0 mph63.0 mph+3.0 mph
75 mph75.0 mph78.7 mph+3.7 mph

Ride-height change: 185/70R13 raises the vehicle by 0.55 in (14.0 mm) at the axle (half the +28.0 mm diameter difference).

185/70R13 is 1.10 in taller than 165/70R13 and 20 mm wider, a 4.99% difference in overall diameter.

With the speedometer calibrated for 165/70R13, an indicated 60 mph is actually 63.0 mph on 185/70R13, and revolutions per mile change from 913 to 869.

Both sizes mount on 13-inch wheels.

Size pages

Other comparisons with 165/70R13

Other comparisons with 185/70R13

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