195/60R16 vs 255/35R18

255/35R18 is 0.19 in (4.7 mm) shorter than 195/60R16, a −0.73% diameter difference. With the speedometer set for 195/60R16, an indicated 60 mph is 59.6 mph on 255/35R18.

Is this a safe swap?

Diameter difference −0.73%: under 1%

By overall diameter alone, 255/35R18 is a near match for 195/60R16; the speedometer changes by less than 1%. 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.

195/60R16 vs 255/35R18 differences
Measurement	195/60R16	255/35R18	Difference	% diff
Overall diameter	25.21 in (640.4 mm)	25.03 in (635.7 mm)	−0.19 in (−4.7 mm)	−0.73%
Sidewall height	4.61 in (117.0 mm)	3.51 in (89.3 mm)	−1.09 in (−27.7 mm)	−23.72%
Section width	7.68 in (195.0 mm)	10.04 in (255.0 mm)	+2.36 in (+60.0 mm)	+30.77%
Circumference	79.21 in (2,011.9 mm)	78.63 in (1,997.1 mm)	−0.58 in (−14.8 mm)	−0.73%
Revolutions per mile	800	806	+6	+0.74%

True speed with the speedometer calibrated for 195/60R16
Indicated	Actual on 195/60R16	Actual on 255/35R18	Difference
30 mph	30.0 mph	29.8 mph	−0.2 mph
60 mph	60.0 mph	59.6 mph	−0.4 mph
75 mph	75.0 mph	74.4 mph	−0.6 mph

Ride-height change: 255/35R18 lowers the vehicle by 0.09 in (2.3 mm) at the axle (half the −4.7 mm diameter difference).

255/35R18 is 0.19 in shorter than 195/60R16 and 60 mm wider, a 0.73% difference in overall diameter.

With the speedometer calibrated for 195/60R16, an indicated 60 mph is actually 59.6 mph on 255/35R18, and revolutions per mile change from 800 to 806.

255/35R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 195/60R16.

Size pages

Other comparisons with 195/60R16

Other comparisons with 255/35R18

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