Tire Size Box

275/40R17 vs 275/50R17

275/50R17 compared with 275/40R17

+8.4% diameter, 0.0" width

275/50R17 is 27.83" tall vs 25.66". More than the 3% rule of thumb, so check carefully before switching.

25.7"17" rim4.3"10.8" wide
275/40R17 (solid) compared with 275/50R17 (dashed outline), drawn to scale

With 275/50R17 tires, when your speedometer says 60 mph you are really going

65.1 mph

275/50R17 is +2.17 inches (+8.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

275/40R17275/50R17Difference%
Overall diameter25.66"27.83"+2.17"+8.4%
Section width10.83"10.83"0.00"0.0%
Sidewall height4.33"5.41"+1.08"+25.0%
Circumference80.62"87.42"+6.80"+8.4%
Revolutions per mile785.9724.8−61.2−7.8%

Speedometer difference

If your vehicle came with 275/40R17 and you fit 275/50R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.7 mph+1.7 mph
30 mph32.5 mph+2.5 mph
40 mph43.4 mph+3.4 mph
50 mph54.2 mph+4.2 mph
60 mph65.1 mph+5.1 mph
65 mph70.5 mph+5.5 mph
70 mph75.9 mph+5.9 mph
75 mph81.3 mph+6.3 mph
80 mph86.8 mph+6.8 mph

Each size on its own

Questions

Which is bigger, 275/40R17 or 275/50R17?
275/50R17 is taller by 2.17 inches (27.83" vs 25.66"). 275/40R17 is the same width.
Can I replace 275/40R17 with 275/50R17?
It is not recommended without checking carefully. The diameter difference is +8.4%, 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 275/50R17 change my speedometer?
When your speedometer reads 60 mph with 275/50R17 fitted (calibrated for 275/40R17), your real speed is 65.1 mph. Your odometer will under-count miles by about 8.4%.
Will 275/50R17 lift my vehicle?
Ride height changes by half the diameter difference: +1.08 inches of ground clearance at the axle.

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