TireSizesFinder

265/70R17 vs 265/65R18

265/65R18 is 0.04 in (1.1 mm) shorter than 265/70R17, a −0.14% diameter difference. With the speedometer set for 265/70R17, an indicated 60 mph is 59.9 mph on 265/65R18.

Is this a safe swap?

Diameter difference −0.14%: under 1%

By overall diameter alone, 265/65R18 is a near match for 265/70R17; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 265/70R17 (31.61 in) vs 265/65R18 (31.56 in)265/70R1731.61 in × 10.43 in265/65R1831.56 in × 10.43 in
Side profile and tread width, drawn to the same scale.
265/70R17 vs 265/65R18 differences
Measurement265/70R17265/65R18Difference% diff
Overall diameter31.61 in (802.8 mm)31.56 in (801.7 mm)−0.04 in (−1.1 mm)−0.14%
Sidewall height7.30 in (185.5 mm)6.78 in (172.3 mm)−0.52 in (−13.2 mm)−7.14%
Section width10.43 in (265.0 mm)10.43 in (265.0 mm)0.00 in (0.0 mm)0.00%
Circumference99.29 in (2,522.1 mm)99.16 in (2,518.6 mm)−0.14 in (−3.5 mm)−0.14%
Revolutions per mile638639+1+0.14%
True speed with the speedometer calibrated for 265/70R17
IndicatedActual on 265/70R17Actual on 265/65R18Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph59.9 mph−0.1 mph
75 mph75.0 mph74.9 mph−0.1 mph

Ride-height change: 265/65R18 lowers the vehicle by 0.02 in (0.5 mm) at the axle (half the −1.1 mm diameter difference).

265/65R18 is 0.04 in shorter than 265/70R17 and the same width, a 0.14% difference in overall diameter.

With the speedometer calibrated for 265/70R17, an indicated 60 mph is actually 59.9 mph on 265/65R18, and revolutions per mile change from 638 to 639.

265/65R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 265/70R17.

Size pages

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