TireSizesFinder

215/50R17 vs 265/35R18

265/35R18 is 0.16 in (4.1 mm) shorter than 215/50R17, a −0.63% diameter difference. With the speedometer set for 215/50R17, an indicated 60 mph is 59.6 mph on 265/35R18.

Is this a safe swap?

Diameter difference −0.63%: under 1%

By overall diameter alone, 265/35R18 is a near match for 215/50R17; 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: 215/50R17 (25.46 in) vs 265/35R18 (25.30 in)215/50R1725.46 in × 8.46 in265/35R1825.30 in × 10.43 in
Side profile and tread width, drawn to the same scale.
215/50R17 vs 265/35R18 differences
Measurement215/50R17265/35R18Difference% diff
Overall diameter25.46 in (646.8 mm)25.30 in (642.7 mm)−0.16 in (−4.1 mm)−0.63%
Sidewall height4.23 in (107.5 mm)3.65 in (92.8 mm)−0.58 in (−14.7 mm)−13.72%
Section width8.46 in (215.0 mm)10.43 in (265.0 mm)+1.97 in (+50.0 mm)+23.26%
Circumference80.00 in (2,032.0 mm)79.49 in (2,019.1 mm)−0.51 in (−12.9 mm)−0.63%
Revolutions per mile792797+5+0.64%
True speed with the speedometer calibrated for 215/50R17
IndicatedActual on 215/50R17Actual on 265/35R18Difference
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: 265/35R18 lowers the vehicle by 0.08 in (2.0 mm) at the axle (half the −4.1 mm diameter difference).

265/35R18 is 0.16 in shorter than 215/50R17 and 50 mm wider, a 0.63% difference in overall diameter.

With the speedometer calibrated for 215/50R17, an indicated 60 mph is actually 59.6 mph on 265/35R18, and revolutions per mile change from 792 to 797.

265/35R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 215/50R17.

Size pages

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