265/35R18 vs 265/30R19

265/30R19 is 0.04 in (1.1 mm) shorter than 265/35R18, a −0.17% diameter difference. With the speedometer set for 265/35R18, an indicated 60 mph is 59.9 mph on 265/30R19.

Is this a safe swap?

Diameter difference −0.17%: under 1%

By overall diameter alone, 265/30R19 is a near match for 265/35R18; 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: 265/35R18 (25.30 in) vs 265/30R19 (25.26 in)265/35R1825.30 in × 10.43 in265/30R1925.26 in × 10.43 in
Side profile and tread width, drawn to the same scale.
265/35R18 vs 265/30R19 differences
Measurement265/35R18265/30R19Difference% diff
Overall diameter25.30 in (642.7 mm)25.26 in (641.6 mm)−0.04 in (−1.1 mm)−0.17%
Sidewall height3.65 in (92.8 mm)3.13 in (79.5 mm)−0.52 in (−13.2 mm)−14.29%
Section width10.43 in (265.0 mm)10.43 in (265.0 mm)0.00 in (0.0 mm)0.00%
Circumference79.49 in (2,019.1 mm)79.36 in (2,015.6 mm)−0.14 in (−3.5 mm)−0.17%
Revolutions per mile797798+1+0.17%
True speed with the speedometer calibrated for 265/35R18
IndicatedActual on 265/35R18Actual on 265/30R19Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.9 mph−0.1 mph
75 mph75.0 mph74.9 mph−0.1 mph

Ride-height change: 265/30R19 lowers the vehicle by 0.02 in (0.6 mm) at the axle (half the −1.1 mm diameter difference).

265/30R19 is 0.04 in shorter than 265/35R18 and the same width, a 0.17% difference in overall diameter.

With the speedometer calibrated for 265/35R18, an indicated 60 mph is actually 59.9 mph on 265/30R19, and revolutions per mile change from 797 to 798.

265/30R19 mounts on a 19-inch wheel, a plus-1 fitment from the 18-inch wheel of 265/35R18.

Size pages

Other comparisons with 265/35R18

Other comparisons with 265/30R19

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