Tire Size Box

325/55R19 vs 325/65R19

325/65R19 compared with 325/55R19

+7.7% diameter, 0.0" width

325/65R19 is 35.63" tall vs 33.07". More than the 3% rule of thumb, so check carefully before switching.

33.1"19" rim7.0"12.8" wide
325/55R19 (solid) compared with 325/65R19 (dashed outline), drawn to scale

With 325/65R19 tires, when your speedometer says 60 mph you are really going

64.6 mph

325/65R19 is +2.56 inches (+7.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

325/55R19325/65R19Difference%
Overall diameter33.07"35.63"+2.56"+7.7%
Section width12.80"12.80"0.00"0.0%
Sidewall height7.04"8.32"+1.28"+18.2%
Circumference103.91"111.95"+8.04"+7.7%
Revolutions per mile609.8566.0−43.8−7.2%

Speedometer difference

If your vehicle came with 325/55R19 and you fit 325/65R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.3 mph+2.3 mph
40 mph43.1 mph+3.1 mph
50 mph53.9 mph+3.9 mph
60 mph64.6 mph+4.6 mph
65 mph70.0 mph+5.0 mph
70 mph75.4 mph+5.4 mph
75 mph80.8 mph+5.8 mph
80 mph86.2 mph+6.2 mph

Each size on its own

Questions

Which is bigger, 325/55R19 or 325/65R19?
325/65R19 is taller by 2.56 inches (35.63" vs 33.07"). 325/55R19 is the same width.
Can I replace 325/55R19 with 325/65R19?
It is not recommended without checking carefully. The diameter difference is +7.7%, 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 325/65R19 change my speedometer?
When your speedometer reads 60 mph with 325/65R19 fitted (calibrated for 325/55R19), your real speed is 64.6 mph. Your odometer will under-count miles by about 7.7%.
Will 325/65R19 lift my vehicle?
Ride height changes by half the diameter difference: +1.28 inches of ground clearance at the axle.

Other comparisons