Tire Size Box

245/35R19 vs 245/45R19

245/45R19 compared with 245/35R19

+7.5% diameter, 0.0" width

245/45R19 is 27.68" tall vs 25.75". More than the 3% rule of thumb, so check carefully before switching.

25.8"19" rim3.4"9.6" wide
245/35R19 (solid) compared with 245/45R19 (dashed outline), drawn to scale

With 245/45R19 tires, when your speedometer says 60 mph you are really going

64.5 mph

245/45R19 is +1.93 inches (+7.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/35R19245/45R19Difference%
Overall diameter25.75"27.68"+1.93"+7.5%
Section width9.65"9.65"0.00"0.0%
Sidewall height3.38"4.34"+0.96"+28.6%
Circumference80.90"86.96"+6.06"+7.5%
Revolutions per mile783.2728.6−54.6−7.0%

Speedometer difference

If your vehicle came with 245/35R19 and you fit 245/45R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.2 mph+2.2 mph
40 mph43.0 mph+3.0 mph
50 mph53.7 mph+3.7 mph
60 mph64.5 mph+4.5 mph
65 mph69.9 mph+4.9 mph
70 mph75.2 mph+5.2 mph
75 mph80.6 mph+5.6 mph
80 mph86.0 mph+6.0 mph

Each size on its own

Questions

Which is bigger, 245/35R19 or 245/45R19?
245/45R19 is taller by 1.93 inches (27.68" vs 25.75"). 245/35R19 is the same width.
Can I replace 245/35R19 with 245/45R19?
It is not recommended without checking carefully. The diameter difference is +7.5%, 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 245/45R19 change my speedometer?
When your speedometer reads 60 mph with 245/45R19 fitted (calibrated for 245/35R19), your real speed is 64.5 mph. Your odometer will under-count miles by about 7.5%.
Will 245/45R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.96 inches of ground clearance at the axle.

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