TireSizesFinder

275/65R18 vs 285/65R18

285/65R18 is 0.51 in (13.0 mm) taller than 275/65R18, a +1.60% diameter difference. With the speedometer set for 275/65R18, an indicated 60 mph is 61.0 mph on 285/65R18.

Is this a safe swap?

Diameter difference +1.60%: within the ±3% guideline

By overall diameter alone, 285/65R18 falls inside the ±3% range commonly used as a guideline when replacing 275/65R18. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 275/65R18 (32.07 in) vs 285/65R18 (32.59 in)275/65R1832.07 in × 10.83 in285/65R1832.59 in × 11.22 in
Side profile and tread width, drawn to the same scale.
275/65R18 vs 285/65R18 differences
Measurement275/65R18285/65R18Difference% diff
Overall diameter32.07 in (814.7 mm)32.59 in (827.7 mm)+0.51 in (+13.0 mm)+1.60%
Sidewall height7.04 in (178.8 mm)7.29 in (185.3 mm)+0.26 in (+6.5 mm)+3.64%
Section width10.83 in (275.0 mm)11.22 in (285.0 mm)+0.39 in (+10.0 mm)+3.64%
Circumference100.77 in (2,559.5 mm)102.37 in (2,600.3 mm)+1.61 in (+40.8 mm)+1.60%
Revolutions per mile629619−10−1.57%
True speed with the speedometer calibrated for 275/65R18
IndicatedActual on 275/65R18Actual on 285/65R18Difference
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: 285/65R18 raises the vehicle by 0.26 in (6.5 mm) at the axle (half the +13.0 mm diameter difference).

285/65R18 is 0.51 in taller than 275/65R18 and 10 mm wider, a 1.60% difference in overall diameter.

With the speedometer calibrated for 275/65R18, an indicated 60 mph is actually 61.0 mph on 285/65R18, and revolutions per mile change from 629 to 619.

Both sizes mount on 18-inch wheels.

Size pages

Other comparisons with 275/65R18

Other comparisons with 285/65R18

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