Tire Size Box

355/25R19 vs 355/30R19

355/30R19 compared with 355/25R19

+5.4% diameter, 0.0" width

355/30R19 is 27.39" tall vs 25.99". More than the 3% rule of thumb, so check carefully before switching.

26.0"19" rim3.5"14.0" wide
355/25R19 (solid) compared with 355/30R19 (dashed outline), drawn to scale

With 355/30R19 tires, when your speedometer says 60 mph you are really going

63.2 mph

355/30R19 is +1.40 inches (+5.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

355/25R19355/30R19Difference%
Overall diameter25.99"27.39"+1.40"+5.4%
Section width13.98"13.98"0.00"0.0%
Sidewall height3.49"4.19"+0.70"+20.0%
Circumference81.64"86.04"+4.39"+5.4%
Revolutions per mile776.0736.4−39.6−5.1%

Speedometer difference

If your vehicle came with 355/25R19 and you fit 355/30R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.1 mph+1.1 mph
30 mph31.6 mph+1.6 mph
40 mph42.2 mph+2.2 mph
50 mph52.7 mph+2.7 mph
60 mph63.2 mph+3.2 mph
65 mph68.5 mph+3.5 mph
70 mph73.8 mph+3.8 mph
75 mph79.0 mph+4.0 mph
80 mph84.3 mph+4.3 mph

Each size on its own

Questions

Which is bigger, 355/25R19 or 355/30R19?
355/30R19 is taller by 1.40 inches (27.39" vs 25.99"). 355/25R19 is the same width.
Can I replace 355/25R19 with 355/30R19?
It is not recommended without checking carefully. The diameter difference is +5.4%, 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 355/30R19 change my speedometer?
When your speedometer reads 60 mph with 355/30R19 fitted (calibrated for 355/25R19), your real speed is 63.2 mph. Your odometer will under-count miles by about 5.4%.
Will 355/30R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.70 inches of ground clearance at the axle.

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