Tire Size Box

275/45R15 vs 275/50R15

275/50R15 compared with 275/45R15

+4.4% diameter, 0.0" width

275/50R15 is 25.83" tall vs 24.74". More than the 3% rule of thumb, so check carefully before switching.

24.7"15" rim4.9"10.8" wide
275/45R15 (solid) compared with 275/50R15 (dashed outline), drawn to scale

With 275/50R15 tires, when your speedometer says 60 mph you are really going

62.6 mph

275/50R15 is +1.08 inches (+4.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

275/45R15275/50R15Difference%
Overall diameter24.74"25.83"+1.08"+4.4%
Section width10.83"10.83"0.00"0.0%
Sidewall height4.87"5.41"+0.54"+11.1%
Circumference77.74"81.14"+3.40"+4.4%
Revolutions per mile815.1780.9−34.2−4.2%

Speedometer difference

If your vehicle came with 275/45R15 and you fit 275/50R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.9 mph+0.9 mph
30 mph31.3 mph+1.3 mph
40 mph41.8 mph+1.8 mph
50 mph52.2 mph+2.2 mph
60 mph62.6 mph+2.6 mph
65 mph67.8 mph+2.8 mph
70 mph73.1 mph+3.1 mph
75 mph78.3 mph+3.3 mph
80 mph83.5 mph+3.5 mph

Each size on its own

Questions

Which is bigger, 275/45R15 or 275/50R15?
275/50R15 is taller by 1.08 inches (25.83" vs 24.74"). 275/45R15 is the same width.
Can I replace 275/45R15 with 275/50R15?
It is not recommended without checking carefully. The diameter difference is +4.4%, 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 275/50R15 change my speedometer?
When your speedometer reads 60 mph with 275/50R15 fitted (calibrated for 275/45R15), your real speed is 62.6 mph. Your odometer will under-count miles by about 4.4%.
Will 275/50R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.54 inches of ground clearance at the axle.

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