TireSizesFinder

205/45R16 vs 205/40R17

205/40R17 is 0.19 in (4.9 mm) taller than 205/45R16, a +0.83% diameter difference. With the speedometer set for 205/45R16, an indicated 60 mph is 60.5 mph on 205/40R17.

Is this a safe swap?

Diameter difference +0.83%: under 1%

By overall diameter alone, 205/40R17 is a near match for 205/45R16; 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: 205/45R16 (23.26 in) vs 205/40R17 (23.46 in)205/45R1623.26 in × 8.07 in205/40R1723.46 in × 8.07 in
Side profile and tread width, drawn to the same scale.
205/45R16 vs 205/40R17 differences
Measurement205/45R16205/40R17Difference% diff
Overall diameter23.26 in (590.9 mm)23.46 in (595.8 mm)+0.19 in (+4.9 mm)+0.83%
Sidewall height3.63 in (92.3 mm)3.23 in (82.0 mm)−0.40 in (−10.2 mm)−11.11%
Section width8.07 in (205.0 mm)8.07 in (205.0 mm)0.00 in (0.0 mm)0.00%
Circumference73.09 in (1,856.4 mm)73.69 in (1,871.8 mm)+0.61 in (+15.4 mm)+0.83%
Revolutions per mile867860−7−0.82%
True speed with the speedometer calibrated for 205/45R16
IndicatedActual on 205/45R16Actual on 205/40R17Difference
30 mph30.0 mph30.2 mph+0.2 mph
60 mph60.0 mph60.5 mph+0.5 mph
75 mph75.0 mph75.6 mph+0.6 mph

Ride-height change: 205/40R17 raises the vehicle by 0.10 in (2.4 mm) at the axle (half the +4.9 mm diameter difference).

205/40R17 is 0.19 in taller than 205/45R16 and the same width, a 0.83% difference in overall diameter.

With the speedometer calibrated for 205/45R16, an indicated 60 mph is actually 60.5 mph on 205/40R17, and revolutions per mile change from 867 to 860.

205/40R17 mounts on a 17-inch wheel, a plus-1 fitment from the 16-inch wheel of 205/45R16.

Size pages

Other comparisons with 205/45R16

Other comparisons with 205/40R17

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