Tire Size Box

275/55R17 vs 275/65R17

275/65R17 compared with 275/55R17

+7.5% diameter, 0.0" width

275/65R17 is 31.07" tall vs 28.91". More than the 3% rule of thumb, so check carefully before switching.

28.9"17" rim6.0"10.8" wide
275/55R17 (solid) compared with 275/65R17 (dashed outline), drawn to scale

With 275/65R17 tires, when your speedometer says 60 mph you are really going

64.5 mph

275/65R17 is +2.17 inches (+7.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

275/55R17275/65R17Difference%
Overall diameter28.91"31.07"+2.17"+7.5%
Section width10.83"10.83"0.00"0.0%
Sidewall height5.95"7.04"+1.08"+18.2%
Circumference90.82"97.62"+6.80"+7.5%
Revolutions per mile697.6649.0−48.6−7.0%

Speedometer difference

If your vehicle came with 275/55R17 and you fit 275/65R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.2 mph+2.2 mph
40 mph43.0 mph+3.0 mph
50 mph53.7 mph+3.7 mph
60 mph64.5 mph+4.5 mph
65 mph69.9 mph+4.9 mph
70 mph75.2 mph+5.2 mph
75 mph80.6 mph+5.6 mph
80 mph86.0 mph+6.0 mph

Each size on its own

Questions

Which is bigger, 275/55R17 or 275/65R17?
275/65R17 is taller by 2.17 inches (31.07" vs 28.91"). 275/55R17 is the same width.
Can I replace 275/55R17 with 275/65R17?
It is not recommended without checking carefully. The diameter difference is +7.5%, 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 275/65R17 change my speedometer?
When your speedometer reads 60 mph with 275/65R17 fitted (calibrated for 275/55R17), your real speed is 64.5 mph. Your odometer will under-count miles by about 7.5%.
Will 275/65R17 lift my vehicle?
Ride height changes by half the diameter difference: +1.08 inches of ground clearance at the axle.

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