Tire Size Box

315/50R20 vs 315/60R20

315/60R20 compared with 315/50R20

+7.7% diameter, 0.0" width

315/60R20 is 34.88" tall vs 32.40". More than the 3% rule of thumb, so check carefully before switching.

32.4"20" rim6.2"12.4" wide
315/50R20 (solid) compared with 315/60R20 (dashed outline), drawn to scale

With 315/60R20 tires, when your speedometer says 60 mph you are really going

64.6 mph

315/60R20 is +2.48 inches (+7.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

315/50R20315/60R20Difference%
Overall diameter32.40"34.88"+2.48"+7.7%
Section width12.40"12.40"0.00"0.0%
Sidewall height6.20"7.44"+1.24"+20.0%
Circumference101.79"109.58"+7.79"+7.7%
Revolutions per mile622.4578.2−44.3−7.1%

Speedometer difference

If your vehicle came with 315/50R20 and you fit 315/60R20, 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 mph43.1 mph+3.1 mph
50 mph53.8 mph+3.8 mph
60 mph64.6 mph+4.6 mph
65 mph70.0 mph+5.0 mph
70 mph75.4 mph+5.4 mph
75 mph80.7 mph+5.7 mph
80 mph86.1 mph+6.1 mph

Each size on its own

Questions

Which is bigger, 315/50R20 or 315/60R20?
315/60R20 is taller by 2.48 inches (34.88" vs 32.40"). 315/50R20 is the same width.
Can I replace 315/50R20 with 315/60R20?
It is not recommended without checking carefully. The diameter difference is +7.7%, 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 315/60R20 change my speedometer?
When your speedometer reads 60 mph with 315/60R20 fitted (calibrated for 315/50R20), your real speed is 64.6 mph. Your odometer will under-count miles by about 7.7%.
Will 315/60R20 lift my vehicle?
Ride height changes by half the diameter difference: +1.24 inches of ground clearance at the axle.

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