Tire Size Box

195/65R18 vs 195/75R18

195/75R18 compared with 195/65R18

+5.5% diameter, 0.0" width

195/75R18 is 29.52" tall vs 27.98". More than the 3% rule of thumb, so check carefully before switching.

28.0"18" rim5.0"7.7" wide
195/65R18 (solid) compared with 195/75R18 (dashed outline), drawn to scale

With 195/75R18 tires, when your speedometer says 60 mph you are really going

63.3 mph

195/75R18 is +1.54 inches (+5.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

195/65R18195/75R18Difference%
Overall diameter27.98"29.52"+1.54"+5.5%
Section width7.68"7.68"0.00"0.0%
Sidewall height4.99"5.76"+0.77"+15.4%
Circumference87.90"92.73"+4.82"+5.5%
Revolutions per mile720.8683.3−37.5−5.2%

Speedometer difference

If your vehicle came with 195/65R18 and you fit 195/75R18, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.1 mph+1.1 mph
30 mph31.6 mph+1.6 mph
40 mph42.2 mph+2.2 mph
50 mph52.7 mph+2.7 mph
60 mph63.3 mph+3.3 mph
65 mph68.6 mph+3.6 mph
70 mph73.8 mph+3.8 mph
75 mph79.1 mph+4.1 mph
80 mph84.4 mph+4.4 mph

Each size on its own

Questions

Which is bigger, 195/65R18 or 195/75R18?
195/75R18 is taller by 1.54 inches (29.52" vs 27.98"). 195/65R18 is the same width.
Can I replace 195/65R18 with 195/75R18?
It is not recommended without checking carefully. The diameter difference is +5.5%, 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 195/75R18 change my speedometer?
When your speedometer reads 60 mph with 195/75R18 fitted (calibrated for 195/65R18), your real speed is 63.3 mph. Your odometer will under-count miles by about 5.5%.
Will 195/75R18 lift my vehicle?
Ride height changes by half the diameter difference: +0.77 inches of ground clearance at the axle.

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