Tire Size Box

225/40R17 vs 225/50R17

225/50R17 compared with 225/40R17

+7.4% diameter, 0.0" width

225/50R17 is 25.86" tall vs 24.09". More than the 3% rule of thumb, so check carefully before switching.

24.1"17" rim3.5"8.9" wide
225/40R17 (solid) compared with 225/50R17 (dashed outline), drawn to scale

With 225/50R17 tires, when your speedometer says 60 mph you are really going

64.4 mph

225/50R17 is +1.77 inches (+7.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/40R17225/50R17Difference%
Overall diameter24.09"25.86"+1.77"+7.4%
Section width8.86"8.86"0.00"0.0%
Sidewall height3.54"4.43"+0.89"+25.0%
Circumference75.67"81.24"+5.57"+7.4%
Revolutions per mile837.3779.9−57.4−6.9%

Speedometer difference

If your vehicle came with 225/40R17 and you fit 225/50R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.2 mph+2.2 mph
40 mph42.9 mph+2.9 mph
50 mph53.7 mph+3.7 mph
60 mph64.4 mph+4.4 mph
65 mph69.8 mph+4.8 mph
70 mph75.1 mph+5.1 mph
75 mph80.5 mph+5.5 mph
80 mph85.9 mph+5.9 mph

Each size on its own

Questions

Which is bigger, 225/40R17 or 225/50R17?
225/50R17 is taller by 1.77 inches (25.86" vs 24.09"). 225/40R17 is the same width.
Can I replace 225/40R17 with 225/50R17?
It is not recommended without checking carefully. The diameter difference is +7.4%, more than the 3% most shops and makers allow. It will throw off the speedometer and may affect ABS, stability control and clearance.
How much will 225/50R17 change my speedometer?
When your speedometer reads 60 mph with 225/50R17 fitted (calibrated for 225/40R17), your real speed is 64.4 mph. Your odometer will under-count miles by about 7.4%.
Will 225/50R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.89 inches of ground clearance at the axle.

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