Tire Size Box

275/50R18 vs 275/60R18

275/60R18 compared with 275/50R18

+7.5% diameter, 0.0" width

275/60R18 is 30.99" tall vs 28.83". More than the 3% rule of thumb, so check carefully before switching.

28.8"18" rim5.4"10.8" wide
275/50R18 (solid) compared with 275/60R18 (dashed outline), drawn to scale

With 275/60R18 tires, when your speedometer says 60 mph you are really going

64.5 mph

275/60R18 is +2.17 inches (+7.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

275/50R18275/60R18Difference%
Overall diameter28.83"30.99"+2.17"+7.5%
Section width10.83"10.83"0.00"0.0%
Sidewall height5.41"6.50"+1.08"+20.0%
Circumference90.56"97.36"+6.80"+7.5%
Revolutions per mile699.6650.7−48.9−7.0%

Speedometer difference

If your vehicle came with 275/50R18 and you fit 275/60R18, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.3 mph+2.3 mph
40 mph43.0 mph+3.0 mph
50 mph53.8 mph+3.8 mph
60 mph64.5 mph+4.5 mph
65 mph69.9 mph+4.9 mph
70 mph75.3 mph+5.3 mph
75 mph80.6 mph+5.6 mph
80 mph86.0 mph+6.0 mph

Each size on its own

Questions

Which is bigger, 275/50R18 or 275/60R18?
275/60R18 is taller by 2.17 inches (30.99" vs 28.83"). 275/50R18 is the same width.
Can I replace 275/50R18 with 275/60R18?
It is not recommended without checking carefully. The diameter difference is +7.5%, 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 275/60R18 change my speedometer?
When your speedometer reads 60 mph with 275/60R18 fitted (calibrated for 275/50R18), your real speed is 64.5 mph. Your odometer will under-count miles by about 7.5%.
Will 275/60R18 lift my vehicle?
Ride height changes by half the diameter difference: +1.08 inches of ground clearance at the axle.

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