225/60R17 vs 265/45R18

265/45R18 is 0.24 in (6.1 mm) shorter than 225/60R17, a −0.87% diameter difference. With the speedometer set for 225/60R17, an indicated 60 mph is 59.5 mph on 265/45R18.

Is this a safe swap?

Diameter difference −0.87%: under 1%

By overall diameter alone, 265/45R18 is a near match for 225/60R17; 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.

225/60R17 vs 265/45R18 differences
Measurement	225/60R17	265/45R18	Difference	% diff
Overall diameter	27.63 in (701.8 mm)	27.39 in (695.7 mm)	−0.24 in (−6.1 mm)	−0.87%
Sidewall height	5.31 in (135.0 mm)	4.69 in (119.3 mm)	−0.62 in (−15.7 mm)	−11.67%
Section width	8.86 in (225.0 mm)	10.43 in (265.0 mm)	+1.57 in (+40.0 mm)	+17.78%
Circumference	86.80 in (2,204.8 mm)	86.05 in (2,185.6 mm)	−0.75 in (−19.2 mm)	−0.87%
Revolutions per mile	730	736	+6	+0.88%

True speed with the speedometer calibrated for 225/60R17
Indicated	Actual on 225/60R17	Actual on 265/45R18	Difference
30 mph	30.0 mph	29.7 mph	−0.3 mph
60 mph	60.0 mph	59.5 mph	−0.5 mph
75 mph	75.0 mph	74.3 mph	−0.7 mph

Ride-height change: 265/45R18 lowers the vehicle by 0.12 in (3.0 mm) at the axle (half the −6.1 mm diameter difference).

265/45R18 is 0.24 in shorter than 225/60R17 and 40 mm wider, a 0.87% difference in overall diameter.

With the speedometer calibrated for 225/60R17, an indicated 60 mph is actually 59.5 mph on 265/45R18, and revolutions per mile change from 730 to 736.

265/45R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 225/60R17.

Size pages

Other comparisons with 225/60R17

Other comparisons with 265/45R18

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