Tire Size Box

245/25R19 vs 235/30R19

235/30R19 compared with 245/25R19

+3.1% diameter, −0.4" width

235/30R19 is 24.55" 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 235/30R19 (dashed outline), drawn to scale

With 235/30R19 tires, when your speedometer says 60 mph you are really going

61.8 mph

235/30R19 is +0.73 inches (+3.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/25R19235/30R19Difference%
Overall diameter23.82"24.55"+0.73"+3.1%
Section width9.65"9.25"−0.39"−4.1%
Sidewall height2.41"2.78"+0.36"+15.1%
Circumference74.84"77.13"+2.29"+3.1%
Revolutions per mile846.6821.5−25.1−3.0%

Speedometer difference

If your vehicle came with 245/25R19 and you fit 235/30R19, 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 mph82.4 mph+2.4 mph

Each size on its own

Questions

Which is bigger, 245/25R19 or 235/30R19?
235/30R19 is taller by 0.73 inches (24.55" vs 23.82"). 245/25R19 is wider by 0.39 inches.
Can I replace 245/25R19 with 235/30R19?
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 235/30R19 change my speedometer?
When your speedometer reads 60 mph with 235/30R19 fitted (calibrated for 245/25R19), your real speed is 61.8 mph. Your odometer will under-count miles by about 3.1%.
Will 235/30R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.36 inches of ground clearance at the axle.

Other comparisons