Tire Size Box

205/40R16 vs 205/50R16

205/50R16 compared with 205/40R16

+7.2% diameter, 0.0" width

205/50R16 is 24.07" tall vs 22.46". More than the 3% rule of thumb, so check carefully before switching.

22.5"16" rim3.2"8.1" wide
205/40R16 (solid) compared with 205/50R16 (dashed outline), drawn to scale

With 205/50R16 tires, when your speedometer says 60 mph you are really going

64.3 mph

205/50R16 is +1.61 inches (+7.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

205/40R16205/50R16Difference%
Overall diameter22.46"24.07"+1.61"+7.2%
Section width8.07"8.07"0.00"0.0%
Sidewall height3.23"4.04"+0.81"+25.0%
Circumference70.55"75.62"+5.07"+7.2%
Revolutions per mile898.1837.9−60.2−6.7%

Speedometer difference

If your vehicle came with 205/40R16 and you fit 205/50R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.2 mph+2.2 mph
40 mph42.9 mph+2.9 mph
50 mph53.6 mph+3.6 mph
60 mph64.3 mph+4.3 mph
65 mph69.7 mph+4.7 mph
70 mph75.0 mph+5.0 mph
75 mph80.4 mph+5.4 mph
80 mph85.8 mph+5.8 mph

Each size on its own

Questions

Which is bigger, 205/40R16 or 205/50R16?
205/50R16 is taller by 1.61 inches (24.07" vs 22.46"). 205/40R16 is the same width.
Can I replace 205/40R16 with 205/50R16?
It is not recommended without checking carefully. The diameter difference is +7.2%, 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 205/50R16 change my speedometer?
When your speedometer reads 60 mph with 205/50R16 fitted (calibrated for 205/40R16), your real speed is 64.3 mph. Your odometer will under-count miles by about 7.2%.
Will 205/50R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.81 inches of ground clearance at the axle.

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