Tire Size Box

215/65R18 vs 215/75R18

215/75R18 compared with 215/65R18

+5.8% diameter, 0.0" width

215/75R18 is 30.70" tall vs 29.00". More than the 3% rule of thumb, so check carefully before switching.

29.0"18" rim5.5"8.5" wide
215/65R18 (solid) compared with 215/75R18 (dashed outline), drawn to scale

With 215/75R18 tires, when your speedometer says 60 mph you are really going

63.5 mph

215/75R18 is +1.69 inches (+5.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/65R18215/75R18Difference%
Overall diameter29.00"30.70"+1.69"+5.8%
Section width8.46"8.46"0.00"0.0%
Sidewall height5.50"6.35"+0.85"+15.4%
Circumference91.12"96.44"+5.32"+5.8%
Revolutions per mile695.4657.0−38.3−5.5%

Speedometer difference

If your vehicle came with 215/65R18 and you fit 215/75R18, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.2 mph+1.2 mph
30 mph31.8 mph+1.8 mph
40 mph42.3 mph+2.3 mph
50 mph52.9 mph+2.9 mph
60 mph63.5 mph+3.5 mph
65 mph68.8 mph+3.8 mph
70 mph74.1 mph+4.1 mph
75 mph79.4 mph+4.4 mph
80 mph84.7 mph+4.7 mph

Each size on its own

Questions

Which is bigger, 215/65R18 or 215/75R18?
215/75R18 is taller by 1.69 inches (30.70" vs 29.00"). 215/65R18 is the same width.
Can I replace 215/65R18 with 215/75R18?
It is not recommended without checking carefully. The diameter difference is +5.8%, 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 215/75R18 change my speedometer?
When your speedometer reads 60 mph with 215/75R18 fitted (calibrated for 215/65R18), your real speed is 63.5 mph. Your odometer will under-count miles by about 5.8%.
Will 215/75R18 lift my vehicle?
Ride height changes by half the diameter difference: +0.85 inches of ground clearance at the axle.

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