TireSizesFinder

245/65R18 vs 265/65R18

265/65R18 is 1.02 in (26.0 mm) taller than 245/65R18, a +3.35% diameter difference. With the speedometer set for 245/65R18, an indicated 60 mph is 62.0 mph on 265/65R18.

Is this a safe swap?

Diameter difference +3.35%: outside the ±3% guideline

By overall diameter alone, 265/65R18 falls outside the ±3% range commonly used as a guideline when replacing 245/65R18; speedometer and ride-height changes are larger. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 245/65R18 (30.54 in) vs 265/65R18 (31.56 in)245/65R1830.54 in × 9.65 in265/65R1831.56 in × 10.43 in
Side profile and tread width, drawn to the same scale.
245/65R18 vs 265/65R18 differences
Measurement245/65R18265/65R18Difference% diff
Overall diameter30.54 in (775.7 mm)31.56 in (801.7 mm)+1.02 in (+26.0 mm)+3.35%
Sidewall height6.27 in (159.3 mm)6.78 in (172.3 mm)+0.51 in (+13.0 mm)+8.16%
Section width9.65 in (245.0 mm)10.43 in (265.0 mm)+0.79 in (+20.0 mm)+8.16%
Circumference95.94 in (2,436.9 mm)99.16 in (2,518.6 mm)+3.22 in (+81.7 mm)+3.35%
Revolutions per mile660639−21−3.24%
True speed with the speedometer calibrated for 245/65R18
IndicatedActual on 245/65R18Actual on 265/65R18Difference
30 mph30.0 mph31.0 mph+1.0 mph
60 mph60.0 mph62.0 mph+2.0 mph
75 mph75.0 mph77.5 mph+2.5 mph

Ride-height change: 265/65R18 raises the vehicle by 0.51 in (13.0 mm) at the axle (half the +26.0 mm diameter difference).

265/65R18 is 1.02 in taller than 245/65R18 and 20 mm wider, a 3.35% difference in overall diameter.

With the speedometer calibrated for 245/65R18, an indicated 60 mph is actually 62.0 mph on 265/65R18, and revolutions per mile change from 660 to 639.

Both sizes mount on 18-inch wheels.

Size pages

Other comparisons with 245/65R18

Other comparisons with 265/65R18

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