Tire Size Box

295/45R21 vs 295/50R21

295/50R21 compared with 295/45R21

+3.7% diameter, 0.0" width

295/50R21 is 32.61" tall vs 31.45". More than the 3% rule of thumb, so check carefully before switching.

31.5"21" rim5.2"11.6" wide
295/45R21 (solid) compared with 295/50R21 (dashed outline), drawn to scale

With 295/50R21 tires, when your speedometer says 60 mph you are really going

62.2 mph

295/50R21 is +1.16 inches (+3.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

295/45R21295/50R21Difference%
Overall diameter31.45"32.61"+1.16"+3.7%
Section width11.61"11.61"0.00"0.0%
Sidewall height5.23"5.81"+0.58"+11.1%
Circumference98.81"102.46"+3.65"+3.7%
Revolutions per mile641.2618.4−22.8−3.6%

Speedometer difference

If your vehicle came with 295/45R21 and you fit 295/50R21, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.5 mph+1.5 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.4 mph+2.4 mph
70 mph72.6 mph+2.6 mph
75 mph77.8 mph+2.8 mph
80 mph83.0 mph+3.0 mph

Each size on its own

Questions

Which is bigger, 295/45R21 or 295/50R21?
295/50R21 is taller by 1.16 inches (32.61" vs 31.45"). 295/45R21 is the same width.
Can I replace 295/45R21 with 295/50R21?
It is not recommended without checking carefully. The diameter difference is +3.7%, 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 295/50R21 change my speedometer?
When your speedometer reads 60 mph with 295/50R21 fitted (calibrated for 295/45R21), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.7%.
Will 295/50R21 lift my vehicle?
Ride height changes by half the diameter difference: +0.58 inches of ground clearance at the axle.

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