TireSizesFinder

215/70R16 vs 245/50R18

245/50R18 is 0.20 in (5.2 mm) shorter than 215/70R16, a −0.74% diameter difference. With the speedometer set for 215/70R16, an indicated 60 mph is 59.6 mph on 245/50R18.

Is this a safe swap?

Diameter difference −0.74%: under 1%

By overall diameter alone, 245/50R18 is a near match for 215/70R16; 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: 215/70R16 (27.85 in) vs 245/50R18 (27.65 in)215/70R1627.85 in × 8.46 in245/50R1827.65 in × 9.65 in
Side profile and tread width, drawn to the same scale.
215/70R16 vs 245/50R18 differences
Measurement215/70R16245/50R18Difference% diff
Overall diameter27.85 in (707.4 mm)27.65 in (702.2 mm)−0.20 in (−5.2 mm)−0.74%
Sidewall height5.93 in (150.5 mm)4.82 in (122.5 mm)−1.10 in (−28.0 mm)−18.60%
Section width8.46 in (215.0 mm)9.65 in (245.0 mm)+1.18 in (+30.0 mm)+13.95%
Circumference87.49 in (2,222.4 mm)86.85 in (2,206.0 mm)−0.64 in (−16.3 mm)−0.74%
Revolutions per mile724730+5+0.74%
True speed with the speedometer calibrated for 215/70R16
IndicatedActual on 215/70R16Actual on 245/50R18Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.6 mph−0.4 mph
75 mph75.0 mph74.4 mph−0.6 mph

Ride-height change: 245/50R18 lowers the vehicle by 0.10 in (2.6 mm) at the axle (half the −5.2 mm diameter difference).

245/50R18 is 0.20 in shorter than 215/70R16 and 30 mm wider, a 0.74% difference in overall diameter.

With the speedometer calibrated for 215/70R16, an indicated 60 mph is actually 59.6 mph on 245/50R18, and revolutions per mile change from 724 to 730.

245/50R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 215/70R16.

Size pages

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