Tire Size Box

295/30R20 vs 285/35R20

285/35R20 compared with 295/30R20

+3.3% diameter, −0.4" width

285/35R20 is 27.85" tall vs 26.97". More than the 3% rule of thumb, so check carefully before switching.

27.0"20" rim3.5"11.6" wide
295/30R20 (solid) compared with 285/35R20 (dashed outline), drawn to scale

With 285/35R20 tires, when your speedometer says 60 mph you are really going

62.0 mph

285/35R20 is +0.89 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

295/30R20285/35R20Difference%
Overall diameter26.97"27.85"+0.89"+3.3%
Section width11.61"11.22"−0.39"−3.4%
Sidewall height3.48"3.93"+0.44"+12.7%
Circumference84.72"87.51"+2.78"+3.3%
Revolutions per mile747.8724.1−23.8−3.2%

Speedometer difference

If your vehicle came with 295/30R20 and you fit 285/35R20, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph62.0 mph+2.0 mph
65 mph67.1 mph+2.1 mph
70 mph72.3 mph+2.3 mph
75 mph77.5 mph+2.5 mph
80 mph82.6 mph+2.6 mph

Each size on its own

Questions

Which is bigger, 295/30R20 or 285/35R20?
285/35R20 is taller by 0.89 inches (27.85" vs 26.97"). 295/30R20 is wider by 0.39 inches.
Can I replace 295/30R20 with 285/35R20?
It is not recommended without checking carefully. The diameter difference is +3.3%, 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 285/35R20 change my speedometer?
When your speedometer reads 60 mph with 285/35R20 fitted (calibrated for 295/30R20), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 285/35R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.44 inches of ground clearance at the axle.

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