Tire Size Box

265/40R16 vs 265/50R16

265/50R16 compared with 265/40R16

+8.6% diameter, 0.0" width

265/50R16 is 26.43" tall vs 24.35". More than the 3% rule of thumb, so check carefully before switching.

24.3"16" rim4.2"10.4" wide
265/40R16 (solid) compared with 265/50R16 (dashed outline), drawn to scale

With 265/50R16 tires, when your speedometer says 60 mph you are really going

65.1 mph

265/50R16 is +2.09 inches (+8.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/40R16265/50R16Difference%
Overall diameter24.35"26.43"+2.09"+8.6%
Section width10.43"10.43"0.00"0.0%
Sidewall height4.17"5.22"+1.04"+25.0%
Circumference76.49"83.04"+6.56"+8.6%
Revolutions per mile828.4763.0−65.4−7.9%

Speedometer difference

If your vehicle came with 265/40R16 and you fit 265/50R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.7 mph+1.7 mph
30 mph32.6 mph+2.6 mph
40 mph43.4 mph+3.4 mph
50 mph54.3 mph+4.3 mph
60 mph65.1 mph+5.1 mph
65 mph70.6 mph+5.6 mph
70 mph76.0 mph+6.0 mph
75 mph81.4 mph+6.4 mph
80 mph86.9 mph+6.9 mph

Each size on its own

Questions

Which is bigger, 265/40R16 or 265/50R16?
265/50R16 is taller by 2.09 inches (26.43" vs 24.35"). 265/40R16 is the same width.
Can I replace 265/40R16 with 265/50R16?
It is not recommended without checking carefully. The diameter difference is +8.6%, 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 265/50R16 change my speedometer?
When your speedometer reads 60 mph with 265/50R16 fitted (calibrated for 265/40R16), your real speed is 65.1 mph. Your odometer will under-count miles by about 8.6%.
Will 265/50R16 lift my vehicle?
Ride height changes by half the diameter difference: +1.04 inches of ground clearance at the axle.

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