Tire Size Box

325/50R20 vs 325/60R20

325/60R20 compared with 325/50R20

+7.8% diameter, 0.0" width

325/60R20 is 35.35" tall vs 32.80". More than the 3% rule of thumb, so check carefully before switching.

32.8"20" rim6.4"12.8" wide
325/50R20 (solid) compared with 325/60R20 (dashed outline), drawn to scale

With 325/60R20 tires, when your speedometer says 60 mph you are really going

64.7 mph

325/60R20 is +2.56 inches (+7.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

325/50R20325/60R20Difference%
Overall diameter32.80"35.35"+2.56"+7.8%
Section width12.80"12.80"0.00"0.0%
Sidewall height6.40"7.68"+1.28"+20.0%
Circumference103.03"111.07"+8.04"+7.8%
Revolutions per mile615.0570.5−44.5−7.2%

Speedometer difference

If your vehicle came with 325/50R20 and you fit 325/60R20, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.6 mph+1.6 mph
30 mph32.3 mph+2.3 mph
40 mph43.1 mph+3.1 mph
50 mph53.9 mph+3.9 mph
60 mph64.7 mph+4.7 mph
65 mph70.1 mph+5.1 mph
70 mph75.5 mph+5.5 mph
75 mph80.9 mph+5.9 mph
80 mph86.2 mph+6.2 mph

Each size on its own

Questions

Which is bigger, 325/50R20 or 325/60R20?
325/60R20 is taller by 2.56 inches (35.35" vs 32.80"). 325/50R20 is the same width.
Can I replace 325/50R20 with 325/60R20?
It is not recommended without checking carefully. The diameter difference is +7.8%, 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 325/60R20 change my speedometer?
When your speedometer reads 60 mph with 325/60R20 fitted (calibrated for 325/50R20), your real speed is 64.7 mph. Your odometer will under-count miles by about 7.8%.
Will 325/60R20 lift my vehicle?
Ride height changes by half the diameter difference: +1.28 inches of ground clearance at the axle.

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