Tire Size Box

285/25R19 vs 275/30R19

275/30R19 compared with 285/25R19

+3.6% diameter, −0.4" width

275/30R19 is 25.50" tall vs 24.61". More than the 3% rule of thumb, so check carefully before switching.

24.6"19" rim2.8"11.2" wide
285/25R19 (solid) compared with 275/30R19 (dashed outline), drawn to scale

With 275/30R19 tires, when your speedometer says 60 mph you are really going

62.2 mph

275/30R19 is +0.89 inches (+3.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

285/25R19275/30R19Difference%
Overall diameter24.61"25.50"+0.89"+3.6%
Section width11.22"10.83"−0.39"−3.5%
Sidewall height2.81"3.25"+0.44"+15.8%
Circumference77.32"80.10"+2.78"+3.6%
Revolutions per mile819.5791.0−28.5−3.5%

Speedometer difference

If your vehicle came with 285/25R19 and you fit 275/30R19, 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 mph41.4 mph+1.4 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.3 mph+2.3 mph
70 mph72.5 mph+2.5 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 285/25R19 or 275/30R19?
275/30R19 is taller by 0.89 inches (25.50" vs 24.61"). 285/25R19 is wider by 0.39 inches.
Can I replace 285/25R19 with 275/30R19?
It is not recommended without checking carefully. The diameter difference is +3.6%, 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 275/30R19 change my speedometer?
When your speedometer reads 60 mph with 275/30R19 fitted (calibrated for 285/25R19), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.6%.
Will 275/30R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.44 inches of ground clearance at the axle.

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