Tire Size Box

245/25R19 vs 245/30R19

245/30R19 compared with 245/25R19

+4.0% diameter, 0.0" width

245/30R19 is 24.79" tall vs 23.82". More than the 3% rule of thumb, so check carefully before switching.

23.8"19" rim2.4"9.6" wide
245/25R19 (solid) compared with 245/30R19 (dashed outline), drawn to scale

With 245/30R19 tires, when your speedometer says 60 mph you are really going

62.4 mph

245/30R19 is +0.96 inches (+4.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/25R19245/30R19Difference%
Overall diameter23.82"24.79"+0.96"+4.0%
Section width9.65"9.65"0.00"0.0%
Sidewall height2.41"2.89"+0.48"+20.0%
Circumference74.84"77.87"+3.03"+4.0%
Revolutions per mile846.6813.6−32.9−3.9%

Speedometer difference

If your vehicle came with 245/25R19 and you fit 245/30R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.2 mph+1.2 mph
40 mph41.6 mph+1.6 mph
50 mph52.0 mph+2.0 mph
60 mph62.4 mph+2.4 mph
65 mph67.6 mph+2.6 mph
70 mph72.8 mph+2.8 mph
75 mph78.0 mph+3.0 mph
80 mph83.2 mph+3.2 mph

Each size on its own

Questions

Which is bigger, 245/25R19 or 245/30R19?
245/30R19 is taller by 0.96 inches (24.79" vs 23.82"). 245/25R19 is the same width.
Can I replace 245/25R19 with 245/30R19?
It is not recommended without checking carefully. The diameter difference is +4.0%, 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 245/30R19 change my speedometer?
When your speedometer reads 60 mph with 245/30R19 fitted (calibrated for 245/25R19), your real speed is 62.4 mph. Your odometer will under-count miles by about 4.0%.
Will 245/30R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.48 inches of ground clearance at the axle.

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