285/65R18 vs 265/70R18

265/70R18 is 0.02 in (0.5 mm) taller than 285/65R18, a +0.06% diameter difference. With the speedometer set for 285/65R18, an indicated 60 mph is 60.0 mph on 265/70R18.

Is this a safe swap?

Diameter difference +0.06%: under 1%

By overall diameter alone, 265/70R18 is a near match for 285/65R18; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

285/65R18 vs 265/70R18 differences
Measurement	285/65R18	265/70R18	Difference	% diff
Overall diameter	32.59 in (827.7 mm)	32.61 in (828.2 mm)	+0.02 in (+0.5 mm)	+0.06%
Sidewall height	7.29 in (185.3 mm)	7.30 in (185.5 mm)	+0.01 in (+0.3 mm)	+0.13%
Section width	11.22 in (285.0 mm)	10.43 in (265.0 mm)	−0.79 in (−20.0 mm)	−7.02%
Circumference	102.37 in (2,600.3 mm)	102.44 in (2,601.9 mm)	+0.06 in (+1.6 mm)	+0.06%
Revolutions per mile	619	619	0	−0.06%

True speed with the speedometer calibrated for 285/65R18
Indicated	Actual on 285/65R18	Actual on 265/70R18
30 mph	30.0 mph	30.0 mph
60 mph	60.0 mph	60.0 mph
75 mph	75.0 mph	75.0 mph

Ride-height change: 265/70R18 raises the vehicle by 0.01 in (0.3 mm) at the axle (half the +0.5 mm diameter difference).

265/70R18 is 0.02 in taller than 285/65R18 and 20 mm narrower, a 0.06% difference in overall diameter.

With the speedometer calibrated for 285/65R18, an indicated 60 mph is actually 60.0 mph on 265/70R18, and revolutions per mile change from 619 to 619.

Both sizes mount on 18-inch wheels.

Size pages

Other comparisons with 285/65R18

Other comparisons with 265/70R18

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.