275/35R18 vs 235/35R19

235/35R19 is 0.10 in (2.6 mm) shorter than 275/35R18, a −0.40% diameter difference. With the speedometer set for 275/35R18, an indicated 60 mph is 59.8 mph on 235/35R19.

Is this a safe swap?

Diameter difference −0.40%: under 1%

By overall diameter alone, 235/35R19 is a near match for 275/35R18; 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: 275/35R18 (25.58 in) vs 235/35R19 (25.48 in)275/35R1825.58 in × 10.83 in235/35R1925.48 in × 9.25 in
Side profile and tread width, drawn to the same scale.
275/35R18 vs 235/35R19 differences
Measurement275/35R18235/35R19Difference% diff
Overall diameter25.58 in (649.7 mm)25.48 in (647.1 mm)−0.10 in (−2.6 mm)−0.40%
Sidewall height3.79 in (96.3 mm)3.24 in (82.3 mm)−0.55 in (−14.0 mm)−14.55%
Section width10.83 in (275.0 mm)9.25 in (235.0 mm)−1.57 in (−40.0 mm)−14.55%
Circumference80.36 in (2,041.1 mm)80.04 in (2,032.9 mm)−0.32 in (−8.2 mm)−0.40%
Revolutions per mile788792+3+0.40%
True speed with the speedometer calibrated for 275/35R18
IndicatedActual on 275/35R18Actual on 235/35R19Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.8 mph−0.2 mph
75 mph75.0 mph74.7 mph−0.3 mph

Ride-height change: 235/35R19 lowers the vehicle by 0.05 in (1.3 mm) at the axle (half the −2.6 mm diameter difference).

235/35R19 is 0.10 in shorter than 275/35R18 and 40 mm narrower, a 0.40% difference in overall diameter.

With the speedometer calibrated for 275/35R18, an indicated 60 mph is actually 59.8 mph on 235/35R19, and revolutions per mile change from 788 to 792.

235/35R19 mounts on a 19-inch wheel, a plus-1 fitment from the 18-inch wheel of 275/35R18.

Size pages

Other comparisons with 275/35R18

Other comparisons with 235/35R19

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