Tire Size Box

225/65R17 vs 245/65R17

245/65R17 compared with 225/65R17

+3.6% diameter, +0.8" width

245/65R17 is 29.54" tall vs 28.52". More than the 3% rule of thumb, so check carefully before switching.

28.5"17" rim5.8"8.9" wide
225/65R17 (solid) compared with 245/65R17 (dashed outline), drawn to scale

With 245/65R17 tires, when your speedometer says 60 mph you are really going

62.2 mph

245/65R17 is +1.02 inches (+3.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/65R17245/65R17Difference%
Overall diameter28.52"29.54"+1.02"+3.6%
Section width8.86"9.65"+0.79"+8.9%
Sidewall height5.76"6.27"+0.51"+8.9%
Circumference89.58"92.80"+3.22"+3.6%
Revolutions per mile707.3682.8−24.5−3.5%

Speedometer difference

If your vehicle came with 225/65R17 and you fit 245/65R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.4 mph+1.4 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.3 mph+2.3 mph
70 mph72.5 mph+2.5 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 225/65R17 or 245/65R17?
245/65R17 is taller by 1.02 inches (29.54" vs 28.52"). 245/65R17 is wider by 0.79 inches.
Can I replace 225/65R17 with 245/65R17?
It is not recommended without checking carefully. The diameter difference is +3.6%, 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 245/65R17 change my speedometer?
When your speedometer reads 60 mph with 245/65R17 fitted (calibrated for 225/65R17), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.6%.
Will 245/65R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.51 inches of ground clearance at the axle.

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