Tire Size Box

215/45R20 vs 215/50R20

215/50R20 compared with 215/45R20

+3.1% diameter, 0.0" width

215/50R20 is 28.46" tall vs 27.62". More than the 3% rule of thumb, so check carefully before switching.

27.6"20" rim3.8"8.5" wide
215/45R20 (solid) compared with 215/50R20 (dashed outline), drawn to scale

With 215/50R20 tires, when your speedometer says 60 mph you are really going

61.8 mph

215/50R20 is +0.85 inches (+3.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/45R20215/50R20Difference%
Overall diameter27.62"28.46"+0.85"+3.1%
Section width8.46"8.46"0.00"0.0%
Sidewall height3.81"4.23"+0.42"+11.1%
Circumference86.76"89.42"+2.66"+3.1%
Revolutions per mile730.2708.5−21.7−3.0%

Speedometer difference

If your vehicle came with 215/45R20 and you fit 215/50R20, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph30.9 mph+0.9 mph
40 mph41.2 mph+1.2 mph
50 mph51.5 mph+1.5 mph
60 mph61.8 mph+1.8 mph
65 mph67.0 mph+2.0 mph
70 mph72.1 mph+2.1 mph
75 mph77.3 mph+2.3 mph
80 mph82.5 mph+2.5 mph

Each size on its own

Questions

Which is bigger, 215/45R20 or 215/50R20?
215/50R20 is taller by 0.85 inches (28.46" vs 27.62"). 215/45R20 is the same width.
Can I replace 215/45R20 with 215/50R20?
It is not recommended without checking carefully. The diameter difference is +3.1%, 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 215/50R20 change my speedometer?
When your speedometer reads 60 mph with 215/50R20 fitted (calibrated for 215/45R20), your real speed is 61.8 mph. Your odometer will under-count miles by about 3.1%.
Will 215/50R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.42 inches of ground clearance at the axle.

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