Tire Size Box

215/85R15 vs 235/85R15

235/85R15 compared with 215/85R15

+4.6% diameter, +0.8" width

235/85R15 is 30.73" tall vs 29.39". More than the 3% rule of thumb, so check carefully before switching.

29.4"15" rim7.2"8.5" wide
215/85R15 (solid) compared with 235/85R15 (dashed outline), drawn to scale

With 235/85R15 tires, when your speedometer says 60 mph you are really going

62.7 mph

235/85R15 is +1.34 inches (+4.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/85R15235/85R15Difference%
Overall diameter29.39"30.73"+1.34"+4.6%
Section width8.46"9.25"+0.79"+9.3%
Sidewall height7.19"7.86"+0.67"+9.3%
Circumference92.33"96.54"+4.21"+4.6%
Revolutions per mile686.2656.3−29.9−4.4%

Speedometer difference

If your vehicle came with 215/85R15 and you fit 235/85R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.9 mph+0.9 mph
30 mph31.4 mph+1.4 mph
40 mph41.8 mph+1.8 mph
50 mph52.3 mph+2.3 mph
60 mph62.7 mph+2.7 mph
65 mph68.0 mph+3.0 mph
70 mph73.2 mph+3.2 mph
75 mph78.4 mph+3.4 mph
80 mph83.6 mph+3.6 mph

Each size on its own

Questions

Which is bigger, 215/85R15 or 235/85R15?
235/85R15 is taller by 1.34 inches (30.73" vs 29.39"). 235/85R15 is wider by 0.79 inches.
Can I replace 215/85R15 with 235/85R15?
It is not recommended without checking carefully. The diameter difference is +4.6%, 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 235/85R15 change my speedometer?
When your speedometer reads 60 mph with 235/85R15 fitted (calibrated for 215/85R15), your real speed is 62.7 mph. Your odometer will under-count miles by about 4.6%.
Will 235/85R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.67 inches of ground clearance at the axle.

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