245/70R17 vs 265/60R18

265/60R18 is 0.02 in (0.4 mm) taller than 245/70R17, a +0.05% diameter difference. With the speedometer set for 245/70R17, an indicated 60 mph is 60.0 mph on 265/60R18.

Is this a safe swap?

Diameter difference +0.05%: under 1%

By overall diameter alone, 265/60R18 is a near match for 245/70R17; 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.

245/70R17 vs 265/60R18 differences
Measurement	245/70R17	265/60R18	Difference	% diff
Overall diameter	30.50 in (774.8 mm)	30.52 in (775.2 mm)	+0.02 in (+0.4 mm)	+0.05%
Sidewall height	6.75 in (171.5 mm)	6.26 in (159.0 mm)	−0.49 in (−12.5 mm)	−7.29%
Section width	9.65 in (245.0 mm)	10.43 in (265.0 mm)	+0.79 in (+20.0 mm)	+8.16%
Circumference	95.83 in (2,434.1 mm)	95.88 in (2,435.4 mm)	+0.05 in (+1.3 mm)	+0.05%
Revolutions per mile	661	661	0	−0.05%

True speed with the speedometer calibrated for 245/70R17
Indicated	Actual on 245/70R17	Actual on 265/60R18
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: 265/60R18 raises the vehicle by 0.01 in (0.2 mm) at the axle (half the +0.4 mm diameter difference).

265/60R18 is 0.02 in taller than 245/70R17 and 20 mm wider, a 0.05% difference in overall diameter.

With the speedometer calibrated for 245/70R17, an indicated 60 mph is actually 60.0 mph on 265/60R18, and revolutions per mile change from 661 to 661.

265/60R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 245/70R17.

Size pages

Other comparisons with 245/70R17

Other comparisons with 265/60R18

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