Tire Size Box

205/85R15 vs 225/85R15

225/85R15 compared with 205/85R15

+4.7% diameter, +0.8" width

225/85R15 is 30.06" tall vs 28.72". More than the 3% rule of thumb, so check carefully before switching.

28.7"15" rim6.9"8.1" wide
205/85R15 (solid) compared with 225/85R15 (dashed outline), drawn to scale

With 225/85R15 tires, when your speedometer says 60 mph you are really going

62.8 mph

225/85R15 is +1.34 inches (+4.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

205/85R15225/85R15Difference%
Overall diameter28.72"30.06"+1.34"+4.7%
Section width8.07"8.86"+0.79"+9.8%
Sidewall height6.86"7.53"+0.67"+9.8%
Circumference90.23"94.43"+4.21"+4.7%
Revolutions per mile702.2670.9−31.3−4.5%

Speedometer difference

If your vehicle came with 205/85R15 and you fit 225/85R15, 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 mph41.9 mph+1.9 mph
50 mph52.3 mph+2.3 mph
60 mph62.8 mph+2.8 mph
65 mph68.0 mph+3.0 mph
70 mph73.3 mph+3.3 mph
75 mph78.5 mph+3.5 mph
80 mph83.7 mph+3.7 mph

Each size on its own

Questions

Which is bigger, 205/85R15 or 225/85R15?
225/85R15 is taller by 1.34 inches (30.06" vs 28.72"). 225/85R15 is wider by 0.79 inches.
Can I replace 205/85R15 with 225/85R15?
It is not recommended without checking carefully. The diameter difference is +4.7%, 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 225/85R15 change my speedometer?
When your speedometer reads 60 mph with 225/85R15 fitted (calibrated for 205/85R15), your real speed is 62.8 mph. Your odometer will under-count miles by about 4.7%.
Will 225/85R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.67 inches of ground clearance at the axle.

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