245/60R16 vs 295/40R18

295/40R18 is 0.28 in (7.2 mm) shorter than 245/60R16, a −1.03% diameter difference. With the speedometer set for 245/60R16, an indicated 60 mph is 59.4 mph on 295/40R18.

Is this a safe swap?

Diameter difference −1.03%: within the ±3% guideline

By overall diameter alone, 295/40R18 falls inside the ±3% range commonly used as a guideline when replacing 245/60R16. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

245/60R16 vs 295/40R18 differences
Measurement	245/60R16	295/40R18	Difference	% diff
Overall diameter	27.57 in (700.4 mm)	27.29 in (693.2 mm)	−0.28 in (−7.2 mm)	−1.03%
Sidewall height	5.79 in (147.0 mm)	4.65 in (118.0 mm)	−1.14 in (−29.0 mm)	−19.73%
Section width	9.65 in (245.0 mm)	11.61 in (295.0 mm)	+1.97 in (+50.0 mm)	+20.41%
Circumference	86.63 in (2,200.4 mm)	85.74 in (2,177.8 mm)	−0.89 in (−22.6 mm)	−1.03%
Revolutions per mile	731	739	+8	+1.04%

True speed with the speedometer calibrated for 245/60R16
Indicated	Actual on 245/60R16	Actual on 295/40R18	Difference
30 mph	30.0 mph	29.7 mph	−0.3 mph
60 mph	60.0 mph	59.4 mph	−0.6 mph
75 mph	75.0 mph	74.2 mph	−0.8 mph

Ride-height change: 295/40R18 lowers the vehicle by 0.14 in (3.6 mm) at the axle (half the −7.2 mm diameter difference).

295/40R18 is 0.28 in shorter than 245/60R16 and 50 mm wider, a 1.03% difference in overall diameter.

With the speedometer calibrated for 245/60R16, an indicated 60 mph is actually 59.4 mph on 295/40R18, and revolutions per mile change from 731 to 739.

295/40R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 245/60R16.

Size pages

Other comparisons with 245/60R16

Other comparisons with 295/40R18

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.