TireSizesFinder

235/45R17 vs 265/35R18

265/35R18 is 0.02 in (0.6 mm) shorter than 235/45R17, a −0.09% diameter difference. With the speedometer set for 235/45R17, an indicated 60 mph is 59.9 mph on 265/35R18.

Is this a safe swap?

Diameter difference −0.09%: under 1%

By overall diameter alone, 265/35R18 is a near match for 235/45R17; 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: 235/45R17 (25.33 in) vs 265/35R18 (25.30 in)235/45R1725.33 in × 9.25 in265/35R1825.30 in × 10.43 in
Side profile and tread width, drawn to the same scale.
235/45R17 vs 265/35R18 differences
Measurement235/45R17265/35R18Difference% diff
Overall diameter25.33 in (643.3 mm)25.30 in (642.7 mm)−0.02 in (−0.6 mm)−0.09%
Sidewall height4.16 in (105.8 mm)3.65 in (92.8 mm)−0.51 in (−13.0 mm)−12.29%
Section width9.25 in (235.0 mm)10.43 in (265.0 mm)+1.18 in (+30.0 mm)+12.77%
Circumference79.57 in (2,021.0 mm)79.49 in (2,019.1 mm)−0.07 in (−1.9 mm)−0.09%
Revolutions per mile796797+1+0.09%
True speed with the speedometer calibrated for 235/45R17
IndicatedActual on 235/45R17Actual on 265/35R18Difference
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: 265/35R18 lowers the vehicle by 0.01 in (0.3 mm) at the axle (half the −0.6 mm diameter difference).

265/35R18 is 0.02 in shorter than 235/45R17 and 30 mm wider, a 0.09% difference in overall diameter.

With the speedometer calibrated for 235/45R17, an indicated 60 mph is actually 59.9 mph on 265/35R18, and revolutions per mile change from 796 to 797.

265/35R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 235/45R17.

Size pages

Other comparisons with 235/45R17

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