Tire Size Box

355/35R19 vs 355/40R19

355/40R19 compared with 355/35R19

+4.9% diameter, 0.0" width

355/40R19 is 30.18" tall vs 28.78". More than the 3% rule of thumb, so check carefully before switching.

28.8"19" rim4.9"14.0" wide
355/35R19 (solid) compared with 355/40R19 (dashed outline), drawn to scale

With 355/40R19 tires, when your speedometer says 60 mph you are really going

62.9 mph

355/40R19 is +1.40 inches (+4.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

355/35R19355/40R19Difference%
Overall diameter28.78"30.18"+1.40"+4.9%
Section width13.98"13.98"0.00"0.0%
Sidewall height4.89"5.59"+0.70"+14.3%
Circumference90.43"94.82"+4.39"+4.9%
Revolutions per mile700.7668.2−32.4−4.6%

Speedometer difference

If your vehicle came with 355/35R19 and you fit 355/40R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.0 mph+1.0 mph
30 mph31.5 mph+1.5 mph
40 mph41.9 mph+1.9 mph
50 mph52.4 mph+2.4 mph
60 mph62.9 mph+2.9 mph
65 mph68.2 mph+3.2 mph
70 mph73.4 mph+3.4 mph
75 mph78.6 mph+3.6 mph
80 mph83.9 mph+3.9 mph

Each size on its own

Questions

Which is bigger, 355/35R19 or 355/40R19?
355/40R19 is taller by 1.40 inches (30.18" vs 28.78"). 355/35R19 is the same width.
Can I replace 355/35R19 with 355/40R19?
It is not recommended without checking carefully. The diameter difference is +4.9%, 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 355/40R19 change my speedometer?
When your speedometer reads 60 mph with 355/40R19 fitted (calibrated for 355/35R19), your real speed is 62.9 mph. Your odometer will under-count miles by about 4.9%.
Will 355/40R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.70 inches of ground clearance at the axle.

Other comparisons