TireSizesFinder

215/50R15 vs 215/40R17

215/40R17 is 0.31 in (7.8 mm) taller than 215/50R15, a +1.31% diameter difference. With the speedometer set for 215/50R15, an indicated 60 mph is 60.8 mph on 215/40R17.

Is this a safe swap?

Diameter difference +1.31%: within the ±3% guideline

By overall diameter alone, 215/40R17 falls inside the ±3% range commonly used as a guideline when replacing 215/50R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 215/50R15 (23.46 in) vs 215/40R17 (23.77 in)215/50R1523.46 in × 8.46 in215/40R1723.77 in × 8.46 in
Side profile and tread width, drawn to the same scale.
215/50R15 vs 215/40R17 differences
Measurement215/50R15215/40R17Difference% diff
Overall diameter23.46 in (596.0 mm)23.77 in (603.8 mm)+0.31 in (+7.8 mm)+1.31%
Sidewall height4.23 in (107.5 mm)3.39 in (86.0 mm)−0.85 in (−21.5 mm)−20.00%
Section width8.46 in (215.0 mm)8.46 in (215.0 mm)0.00 in (0.0 mm)0.00%
Circumference73.72 in (1,872.4 mm)74.68 in (1,896.9 mm)+0.96 in (+24.5 mm)+1.31%
Revolutions per mile860848−11−1.29%
True speed with the speedometer calibrated for 215/50R15
IndicatedActual on 215/50R15Actual on 215/40R17Difference
30 mph30.0 mph30.4 mph+0.4 mph
60 mph60.0 mph60.8 mph+0.8 mph
75 mph75.0 mph76.0 mph+1.0 mph

Ride-height change: 215/40R17 raises the vehicle by 0.15 in (3.9 mm) at the axle (half the +7.8 mm diameter difference).

215/40R17 is 0.31 in taller than 215/50R15 and the same width, a 1.31% difference in overall diameter.

With the speedometer calibrated for 215/50R15, an indicated 60 mph is actually 60.8 mph on 215/40R17, and revolutions per mile change from 860 to 848.

215/40R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 215/50R15.

Size pages

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