TireSizesFinder

305/70R16 vs 265/70R18

265/70R18 is 0.20 in (5.2 mm) shorter than 305/70R16, a −0.62% diameter difference. With the speedometer set for 305/70R16, an indicated 60 mph is 59.6 mph on 265/70R18.

Is this a safe swap?

Diameter difference −0.62%: under 1%

By overall diameter alone, 265/70R18 is a near match for 305/70R16; 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: 305/70R16 (32.81 in) vs 265/70R18 (32.61 in)305/70R1632.81 in × 12.01 in265/70R1832.61 in × 10.43 in
Side profile and tread width, drawn to the same scale.
305/70R16 vs 265/70R18 differences
Measurement305/70R16265/70R18Difference% diff
Overall diameter32.81 in (833.4 mm)32.61 in (828.2 mm)−0.20 in (−5.2 mm)−0.62%
Sidewall height8.41 in (213.5 mm)7.30 in (185.5 mm)−1.10 in (−28.0 mm)−13.11%
Section width12.01 in (305.0 mm)10.43 in (265.0 mm)−1.57 in (−40.0 mm)−13.11%
Circumference103.08 in (2,618.2 mm)102.44 in (2,601.9 mm)−0.64 in (−16.3 mm)−0.62%
Revolutions per mile615619+4+0.63%
True speed with the speedometer calibrated for 305/70R16
IndicatedActual on 305/70R16Actual on 265/70R18Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.6 mph−0.4 mph
75 mph75.0 mph74.5 mph−0.5 mph

Ride-height change: 265/70R18 lowers the vehicle by 0.10 in (2.6 mm) at the axle (half the −5.2 mm diameter difference).

265/70R18 is 0.20 in shorter than 305/70R16 and 40 mm narrower, a 0.62% difference in overall diameter.

With the speedometer calibrated for 305/70R16, an indicated 60 mph is actually 59.6 mph on 265/70R18, and revolutions per mile change from 615 to 619.

265/70R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 305/70R16.

Size pages

Other comparisons with 305/70R16

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