Tire Size Box

235/50R18 vs 235/60R18

235/60R18 compared with 235/50R18

+6.8% diameter, 0.0" width

235/60R18 is 29.10" tall vs 27.25". More than the 3% rule of thumb, so check carefully before switching.

27.3"18" rim4.6"9.3" wide
235/50R18 (solid) compared with 235/60R18 (dashed outline), drawn to scale

With 235/60R18 tires, when your speedometer says 60 mph you are really going

64.1 mph

235/60R18 is +1.85 inches (+6.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/50R18235/60R18Difference%
Overall diameter27.25"29.10"+1.85"+6.8%
Section width9.25"9.25"0.00"0.0%
Sidewall height4.63"5.55"+0.93"+20.0%
Circumference85.61"91.43"+5.81"+6.8%
Revolutions per mile740.1693.0−47.1−6.4%

Speedometer difference

If your vehicle came with 235/50R18 and you fit 235/60R18, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.0 mph+2.0 mph
40 mph42.7 mph+2.7 mph
50 mph53.4 mph+3.4 mph
60 mph64.1 mph+4.1 mph
65 mph69.4 mph+4.4 mph
70 mph74.8 mph+4.8 mph
75 mph80.1 mph+5.1 mph
80 mph85.4 mph+5.4 mph

Each size on its own

Questions

Which is bigger, 235/50R18 or 235/60R18?
235/60R18 is taller by 1.85 inches (29.10" vs 27.25"). 235/50R18 is the same width.
Can I replace 235/50R18 with 235/60R18?
It is not recommended without checking carefully. The diameter difference is +6.8%, 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 235/60R18 change my speedometer?
When your speedometer reads 60 mph with 235/60R18 fitted (calibrated for 235/50R18), your real speed is 64.1 mph. Your odometer will under-count miles by about 6.8%.
Will 235/60R18 lift my vehicle?
Ride height changes by half the diameter difference: +0.93 inches of ground clearance at the axle.

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