195/55R16 vs 245/40R17

245/40R17 is 0.27 in (6.9 mm) taller than 195/55R16, a +1.11% diameter difference. With the speedometer set for 195/55R16, an indicated 60 mph is 60.7 mph on 245/40R17.

Is this a safe swap?

Diameter difference +1.11%: within the ±3% guideline

By overall diameter alone, 245/40R17 falls inside the ±3% range commonly used as a guideline when replacing 195/55R16. 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.

195/55R16 vs 245/40R17 differences
Measurement	195/55R16	245/40R17	Difference	% diff
Overall diameter	24.44 in (620.9 mm)	24.72 in (627.8 mm)	+0.27 in (+6.9 mm)	+1.11%
Sidewall height	4.22 in (107.3 mm)	3.86 in (98.0 mm)	−0.36 in (−9.2 mm)	−8.62%
Section width	7.68 in (195.0 mm)	9.65 in (245.0 mm)	+1.97 in (+50.0 mm)	+25.64%
Circumference	76.80 in (1,950.6 mm)	77.65 in (1,972.3 mm)	+0.85 in (+21.7 mm)	+1.11%
Revolutions per mile	825	816	−9	−1.10%

True speed with the speedometer calibrated for 195/55R16
Indicated	Actual on 195/55R16	Actual on 245/40R17	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.7 mph	+0.7 mph
75 mph	75.0 mph	75.8 mph	+0.8 mph

Ride-height change: 245/40R17 raises the vehicle by 0.14 in (3.4 mm) at the axle (half the +6.9 mm diameter difference).

245/40R17 is 0.27 in taller than 195/55R16 and 50 mm wider, a 1.11% difference in overall diameter.

With the speedometer calibrated for 195/55R16, an indicated 60 mph is actually 60.7 mph on 245/40R17, and revolutions per mile change from 825 to 816.

245/40R17 mounts on a 17-inch wheel, a plus-1 fitment from the 16-inch wheel of 195/55R16.

Size pages

Other comparisons with 195/55R16

Other comparisons with 245/40R17

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