Tire Size Box

285/65R19 vs 305/65R19

305/65R19 compared with 285/65R19

+3.0% diameter, +0.8" width

305/65R19 is 34.61" tall vs 33.59". More than the 3% rule of thumb, so check carefully before switching.

33.6"19" rim7.3"11.2" wide
285/65R19 (solid) compared with 305/65R19 (dashed outline), drawn to scale

With 305/65R19 tires, when your speedometer says 60 mph you are really going

61.8 mph

305/65R19 is +1.02 inches (+3.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

285/65R19305/65R19Difference%
Overall diameter33.59"34.61"+1.02"+3.0%
Section width11.22"12.01"+0.79"+7.0%
Sidewall height7.29"7.81"+0.51"+7.0%
Circumference105.52"108.73"+3.22"+3.0%
Revolutions per mile600.5582.7−17.8−3.0%

Speedometer difference

If your vehicle came with 285/65R19 and you fit 305/65R19, 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, 285/65R19 or 305/65R19?
305/65R19 is taller by 1.02 inches (34.61" vs 33.59"). 305/65R19 is wider by 0.79 inches.
Can I replace 285/65R19 with 305/65R19?
It is not recommended without checking carefully. The diameter difference is +3.0%, 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 305/65R19 change my speedometer?
When your speedometer reads 60 mph with 305/65R19 fitted (calibrated for 285/65R19), your real speed is 61.8 mph. Your odometer will under-count miles by about 3.0%.
Will 305/65R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.51 inches of ground clearance at the axle.

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