TireSizesFinder

185/60R16 vs 245/40R17

245/40R17 is 0.02 in (0.6 mm) shorter than 185/60R16, a −0.10% diameter difference. With the speedometer set for 185/60R16, an indicated 60 mph is 59.9 mph on 245/40R17.

Is this a safe swap?

Diameter difference −0.10%: under 1%

By overall diameter alone, 245/40R17 is a near match for 185/60R16; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 185/60R16 (24.74 in) vs 245/40R17 (24.72 in)185/60R1624.74 in × 7.28 in245/40R1724.72 in × 9.65 in
Side profile and tread width, drawn to the same scale.
185/60R16 vs 245/40R17 differences
Measurement185/60R16245/40R17Difference% diff
Overall diameter24.74 in (628.4 mm)24.72 in (627.8 mm)−0.02 in (−0.6 mm)−0.10%
Sidewall height4.37 in (111.0 mm)3.86 in (98.0 mm)−0.51 in (−13.0 mm)−11.71%
Section width7.28 in (185.0 mm)9.65 in (245.0 mm)+2.36 in (+60.0 mm)+32.43%
Circumference77.72 in (1,974.2 mm)77.65 in (1,972.3 mm)−0.07 in (−1.9 mm)−0.10%
Revolutions per mile815816+1+0.10%
True speed with the speedometer calibrated for 185/60R16
IndicatedActual on 185/60R16Actual on 245/40R17Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph59.9 mph−0.1 mph
75 mph75.0 mph74.9 mph−0.1 mph

Ride-height change: 245/40R17 lowers the vehicle by 0.01 in (0.3 mm) at the axle (half the −0.6 mm diameter difference).

245/40R17 is 0.02 in shorter than 185/60R16 and 60 mm wider, a 0.10% difference in overall diameter.

With the speedometer calibrated for 185/60R16, an indicated 60 mph is actually 59.9 mph on 245/40R17, and revolutions per mile change from 815 to 816.

245/40R17 mounts on a 17-inch wheel, a plus-1 fitment from the 16-inch wheel of 185/60R16.

Size pages

Other comparisons with 185/60R16

Other comparisons with 245/40R17

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