Tire Size Box

215/65R20 vs 235/65R20

235/65R20 compared with 215/65R20

+3.3% diameter, +0.8" width

235/65R20 is 32.03" tall vs 31.00". More than the 3% rule of thumb, so check carefully before switching.

31.0"20" rim5.5"8.5" wide
215/65R20 (solid) compared with 235/65R20 (dashed outline), drawn to scale

With 235/65R20 tires, when your speedometer says 60 mph you are really going

62.0 mph

235/65R20 is +1.02 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/65R20235/65R20Difference%
Overall diameter31.00"32.03"+1.02"+3.3%
Section width8.46"9.25"+0.79"+9.3%
Sidewall height5.50"6.01"+0.51"+9.3%
Circumference97.40"100.62"+3.22"+3.3%
Revolutions per mile650.5629.7−20.8−3.2%

Speedometer difference

If your vehicle came with 215/65R20 and you fit 235/65R20, 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 mph51.7 mph+1.7 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, 215/65R20 or 235/65R20?
235/65R20 is taller by 1.02 inches (32.03" vs 31.00"). 235/65R20 is wider by 0.79 inches.
Can I replace 215/65R20 with 235/65R20?
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 235/65R20 change my speedometer?
When your speedometer reads 60 mph with 235/65R20 fitted (calibrated for 215/65R20), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 235/65R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.51 inches of ground clearance at the axle.

Other comparisons