Tire Size Box

345/35R19 vs 345/45R19

345/45R19 compared with 345/35R19

+9.5% diameter, 0.0" width

345/45R19 is 31.22" tall vs 28.51". More than the 3% rule of thumb, so check carefully before switching.

28.5"19" rim4.8"13.6" wide
345/35R19 (solid) compared with 345/45R19 (dashed outline), drawn to scale

With 345/45R19 tires, when your speedometer says 60 mph you are really going

65.7 mph

345/45R19 is +2.72 inches (+9.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

345/35R19345/45R19Difference%
Overall diameter28.51"31.22"+2.72"+9.5%
Section width13.58"13.58"0.00"0.0%
Sidewall height4.75"6.11"+1.36"+28.6%
Circumference89.56"98.09"+8.53"+9.5%
Revolutions per mile707.5645.9−61.5−8.7%

Speedometer difference

If your vehicle came with 345/35R19 and you fit 345/45R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.9 mph+1.9 mph
30 mph32.9 mph+2.9 mph
40 mph43.8 mph+3.8 mph
50 mph54.8 mph+4.8 mph
60 mph65.7 mph+5.7 mph
65 mph71.2 mph+6.2 mph
70 mph76.7 mph+6.7 mph
75 mph82.1 mph+7.1 mph
80 mph87.6 mph+7.6 mph

Each size on its own

Questions

Which is bigger, 345/35R19 or 345/45R19?
345/45R19 is taller by 2.72 inches (31.22" vs 28.51"). 345/35R19 is the same width.
Can I replace 345/35R19 with 345/45R19?
It is not recommended without checking carefully. The diameter difference is +9.5%, 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 345/45R19 change my speedometer?
When your speedometer reads 60 mph with 345/45R19 fitted (calibrated for 345/35R19), your real speed is 65.7 mph. Your odometer will under-count miles by about 9.5%.
Will 345/45R19 lift my vehicle?
Ride height changes by half the diameter difference: +1.36 inches of ground clearance at the axle.

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