TireSizesFinder

265/65R17 vs 245/65R18

245/65R18 is 0.02 in (0.6 mm) shorter than 265/65R17, a −0.08% diameter difference. With the speedometer set for 265/65R17, an indicated 60 mph is 60.0 mph on 245/65R18.

Is this a safe swap?

Diameter difference −0.08%: under 1%

By overall diameter alone, 245/65R18 is a near match for 265/65R17; 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: 265/65R17 (30.56 in) vs 245/65R18 (30.54 in)265/65R1730.56 in × 10.43 in245/65R1830.54 in × 9.65 in
Side profile and tread width, drawn to the same scale.
265/65R17 vs 245/65R18 differences
Measurement265/65R17245/65R18Difference% diff
Overall diameter30.56 in (776.3 mm)30.54 in (775.7 mm)−0.02 in (−0.6 mm)−0.08%
Sidewall height6.78 in (172.3 mm)6.27 in (159.3 mm)−0.51 in (−13.0 mm)−7.55%
Section width10.43 in (265.0 mm)9.65 in (245.0 mm)−0.79 in (−20.0 mm)−7.55%
Circumference96.02 in (2,438.8 mm)95.94 in (2,436.9 mm)−0.07 in (−1.9 mm)−0.08%
Revolutions per mile660660+1+0.08%
True speed with the speedometer calibrated for 265/65R17
IndicatedActual on 265/65R17Actual on 245/65R18Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph60.0 mph0.0 mph
75 mph75.0 mph74.9 mph−0.1 mph

Ride-height change: 245/65R18 lowers the vehicle by 0.01 in (0.3 mm) at the axle (half the −0.6 mm diameter difference).

245/65R18 is 0.02 in shorter than 265/65R17 and 20 mm narrower, a 0.08% difference in overall diameter.

With the speedometer calibrated for 265/65R17, an indicated 60 mph is actually 60.0 mph on 245/65R18, and revolutions per mile change from 660 to 660.

245/65R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 265/65R17.

Size pages

Other comparisons with 265/65R17

Other comparisons with 245/65R18

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