Tire Size Box

215/30R19 vs 215/40R19

215/40R19 compared with 215/30R19

+7.0% diameter, 0.0" width

215/40R19 is 25.77" tall vs 24.08". More than the 3% rule of thumb, so check carefully before switching.

24.1"19" rim2.5"8.5" wide
215/30R19 (solid) compared with 215/40R19 (dashed outline), drawn to scale

With 215/40R19 tires, when your speedometer says 60 mph you are really going

64.2 mph

215/40R19 is +1.69 inches (+7.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/30R19215/40R19Difference%
Overall diameter24.08"25.77"+1.69"+7.0%
Section width8.46"8.46"0.00"0.0%
Sidewall height2.54"3.39"+0.85"+33.3%
Circumference75.65"80.96"+5.32"+7.0%
Revolutions per mile837.6782.6−55.0−6.6%

Speedometer difference

If your vehicle came with 215/30R19 and you fit 215/40R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.1 mph+2.1 mph
40 mph42.8 mph+2.8 mph
50 mph53.5 mph+3.5 mph
60 mph64.2 mph+4.2 mph
65 mph69.6 mph+4.6 mph
70 mph74.9 mph+4.9 mph
75 mph80.3 mph+5.3 mph
80 mph85.6 mph+5.6 mph

Each size on its own

Questions

Which is bigger, 215/30R19 or 215/40R19?
215/40R19 is taller by 1.69 inches (25.77" vs 24.08"). 215/30R19 is the same width.
Can I replace 215/30R19 with 215/40R19?
It is not recommended without checking carefully. The diameter difference is +7.0%, 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 215/40R19 change my speedometer?
When your speedometer reads 60 mph with 215/40R19 fitted (calibrated for 215/30R19), your real speed is 64.2 mph. Your odometer will under-count miles by about 7.0%.
Will 215/40R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.85 inches of ground clearance at the axle.

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