Tire Size Box

315/35R19 vs 315/45R19

315/45R19 compared with 315/35R19

+9.0% diameter, 0.0" width

315/45R19 is 30.16" tall vs 27.68". More than the 3% rule of thumb, so check carefully before switching.

27.7"19" rim4.3"12.4" wide
315/35R19 (solid) compared with 315/45R19 (dashed outline), drawn to scale

With 315/45R19 tires, when your speedometer says 60 mph you are really going

65.4 mph

315/45R19 is +2.48 inches (+9.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

315/35R19315/45R19Difference%
Overall diameter27.68"30.16"+2.48"+9.0%
Section width12.40"12.40"0.00"0.0%
Sidewall height4.34"5.58"+1.24"+28.6%
Circumference86.96"94.75"+7.79"+9.0%
Revolutions per mile728.6668.7−59.9−8.2%

Speedometer difference

If your vehicle came with 315/35R19 and you fit 315/45R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.8 mph+1.8 mph
30 mph32.7 mph+2.7 mph
40 mph43.6 mph+3.6 mph
50 mph54.5 mph+4.5 mph
60 mph65.4 mph+5.4 mph
65 mph70.8 mph+5.8 mph
70 mph76.3 mph+6.3 mph
75 mph81.7 mph+6.7 mph
80 mph87.2 mph+7.2 mph

Each size on its own

Questions

Which is bigger, 315/35R19 or 315/45R19?
315/45R19 is taller by 2.48 inches (30.16" vs 27.68"). 315/35R19 is the same width.
Can I replace 315/35R19 with 315/45R19?
It is not recommended without checking carefully. The diameter difference is +9.0%, 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 315/45R19 change my speedometer?
When your speedometer reads 60 mph with 315/45R19 fitted (calibrated for 315/35R19), your real speed is 65.4 mph. Your odometer will under-count miles by about 9.0%.
Will 315/45R19 lift my vehicle?
Ride height changes by half the diameter difference: +1.24 inches of ground clearance at the axle.

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